# concrete form release



## user1007 (Sep 23, 2009)

Latex paint is not going to be much of a release agent. There are all kinds of release agents you can put on for concrete form release---even over fillers you have used to even out defects in the form surface. Check to see what your building supply company has availed.


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## jomama45 (Nov 13, 2008)

Personally, I'd skip the paint. It could very well end up coming off of the forms & sticking to your walls, creating one more step than necessary.

Diesel is OK, as long as it's mixed about 50/50 with a heavy oil IMO. Otherwise, just about any thin oil will work, including vegetable oil you already have in the kitchen.

If you want a smoother finish you'll probably have to either sand the plywood first, or rub the wall out later.


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## Bud Cline (Mar 12, 2006)

Any depression in the plywood that would require fill would result in a protrusion in the poured wall if not filled in the plywood. (basic) 

so...
Why not leave it as-is, go ahead and pour the concrete, and then remove the forms as soon as practical and rub the wall's surface with a rubbing stone while it is still green?


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## Gary in WA (Mar 11, 2009)

Put some 4mill poly on them before assembling or spray them with sugar water mix before pouring. Don't spray anything on the stub steel or re-bar, though. Gives more time to trowel smooth right after stripping.

Gary


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

GBR in WA said:


> Put some 4mill poly on them before assembling or spray them with sugar water mix before pouring. Don't spray anything on the stub steel or re-bar, though. Gives more time to trowel smooth right after stripping.
> 
> Gary


Plastic sounds like a good solution. And then I could leave the forms on for a couple of weeks to help with the curing. Is there any potential problem with this? Btw, the wall is about 6' high, if that makes a difference. Thanks.


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## Bud Cline (Mar 12, 2006)

Plastic film will transmit any imperfections that may exist in the plywood. The longer you wait to break forms the harder it will be to correct the wall's appearance. If you break the forms ASAP the wall can be uniformly scuffed/rubbed overall for a nice finish. If you wait a couple of weeks the task will change and not for the better. If you think you have to slow the cure of the wall for more strength then bust the forms ASAP, rub the surface, then cover it with plastic for a couple of weeks if you think there is something to be gained by doing so.


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## rustyjames (Jul 20, 2008)

Diesel as a release agent is probably not allowed in all the 50 states.


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## Gary in WA (Mar 11, 2009)

As Bud brought out correctly in post #7. Jeremy, you must have skipped this from my answer "*Gives more time to trowel smooth right after stripping*." You obviously can't wait more than an hour, depends on weather, ingredients, etc.

Gary


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## STL B. (Oct 29, 2010)

Stop by a concrete contracters yard and offer $10-$15 for a gal. or two for form oil. I think deisel fuel would work fine or you could mix it with kerosene.........I think canola would work fine also, as long as you strip your forms the following day.

As far as smoothing out the surface I'd just plan on skimming the wall with mortar the day you strip. That will fill in all of the "honeycomb" or air that doesnt get vibirated out of the mix, it will give a even color also.


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## STL B. (Oct 29, 2010)

> You obviously can't wait more than an hour


I've never seen a wall form striped the same day it was poured much less within hours.


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## jomama45 (Nov 13, 2008)

STL B. said:


> I've never seen a wall form striped the same day it was poured much less within hours.


I've never actually seen it either, although my Dad insists he poured and stripped a basement in the same day many moons ago.........

It's certainly not something I would suggest for a DIY trial though. A curb, maybe, but not a 6' high wall.


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## Bud Cline (Mar 12, 2006)

> or air that doesnt get *vibirated* out of the mix


*Oh Lordy!* Wish you hadn't brought that up.:no:
A concrete vibrator in the hands of the inexperienced can result in disaster.

Sh-h-h-h-h-h! He'll be fine as-is, no vibrators.


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## SteelToes (Oct 5, 2010)

I've seen forms striped the same day ... but these where some skinny columns in between block wall not a 6' retaining wall.

I think if you strip em down next morning you will still be able to scrape some of the stuff of.

I've seen plastic used in couple occasions...it will leave surface perfectly smooth in the areas where is stretched out but man will it leave a mess if it gets crumpled up or concrete gets behind it.

I've actually spent few weeks fixing a ceiling that was poured with plastic visqueen over the forms (Europe).
I was not there while they where pouring that ceiling but my "guess" would be that they didn't secure the plastic to the plywood and stuff got all crumpled up in between rebar.
You guys wouldn't believe how bad did that ceiling look like.

There are different grades of plywood.. if you are going to use a CDX ply for the forms there is no "oil" or paint on this world that will cover all of those holes.

Use one smooth side plywood ,oil and VIBRATOR and you will achieve some very satisfying results.
*
Oh Lordy!*_ Wish you hadn't brought that up.:no:
A concrete vibrator in the hands of the inexperienced can result in disaster.

Sh-h-h-h-h-h! He'll be fine as-is, no vibrators._

What is going to happen if he uses a shaft vibrator? 

Skim coating over newly poured stuf will work but you are looking at the work that can be avoided now using better plywood.

AC or BX ply its only 20% more than CDX and unless you are doing a mile long retaining wall that is a money well spent.


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## Bud Cline (Mar 12, 2006)

Steel Toes this site has some fairly nifty features for quoting and stuff like that. You should learn to use them. It would make your comments easier to understand.



> What is going to happen if he uses a shaft vibrator?


You have never seen wall-forms blow out from the over-use of a vibrator have you? It's not a pretty sight, and it's not easy to clean up. He doesn't need a vibrator necessarily.


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## SteelToes (Oct 5, 2010)

Bud Cline said:


> Steel Toes this site has some fairly nifty features for quoting and stuff like that. You should learn to use them. It would make your comments easier to understand.
> 
> 
> You have never seen wall-forms blow out from the over-use of a vibrator have you? It's not a pretty sight, and it's not easy to clean up. He doesn't need a vibrator necessarily.




I know Bud but my brain doesn’t always listen to me nor it does things in order :lol:
I spend one of my summer breaks working for the company that was specialized in building weight stations.
I was that new guy assigned to work with concrete vibrator. :furious::furious:

No they don’t need a vibrator, necessarily, but one would definitely help them achieve what they want.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

GBR in WA said:


> As Bud brought out correctly in post #7. Jeremy, you must have skipped this from my answer "*Gives more time to trowel smooth right after stripping*." You obviously can't wait more than an hour, depends on weather, ingredients, etc.
> 
> Gary


I still haven't seen a response regarding this "can't wait more than an hour" comment. It seems kinda daffy to me.

I've used a concrete vibrator before, without incident. I think it's necessary on a wall like this, particularly since the concrete has to be pumped. In any case, I'll have some experienced help for the actual pour---I'm just trying to do a much of the prep as I can by myself.

After further reflection, I think I'll not worry about the smoothness issue, since the visible parts will probably (eventually) get covered with something (although eventually can be a long time...). But, I am intrigued about using plastic inside the forms, since I'd like to keep it damp and cure it properly.


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## STL B. (Oct 29, 2010)

> Skim coating over newly poured stuf will work but you are looking at the work that can be avoided now using better plywood.
> 
> AC or BX ply its only 20% more than CDX and unless you are doing a mile long retaining wall that is a money well spent.


Good advice.





> You have never seen wall-forms blow out from the over-use of a vibrator have you? It's not a pretty sight, and it's not easy to clean up. He doesn't need a vibrator necessarily.


I've had them bow, buckle, moan and groan but I've never a true blow-out, and I've poured some really crappy looking forms built by really crappy carpenters. So I dont think that it would be to hard for a home owner to build forms strong enough to vibrate. 

I do believe that any wall poured and not vibrated was not done correctly. It's not a hard tool to learn how to use, I got a 60sec. lesson once as the pre-mix trucks were pulling into the lot. You just drop the dick in the mix and let it fall at it's own pace when it hits bottom or close to it you pull it out at the same rate that it fell......overlap the pattern by 1/3 all the way down the wall. 





> I was that new guy assigned to work with concrete vibrator. :furious::furious:


What's to gripe about thats one of the best jobs on a large concrete pour. I learned the same way but contractors really really like to have a crew with plenty of experiance climbing around on large walls.........It makes for job security and it feels nice standing up high on the forms watching everyone else dig trenches


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## STL B. (Oct 29, 2010)

> I am intrigued about using plastic inside the forms, since I'd like to keep it damp and cure it properly.


Dont do it, as someone else mentioned if it's not perfectly flat against the forms you'll end up with some really ugly puckers/wrinkels on your wall. It will also leave a glass smooth glossy finish, exterior concrete should'nt have that glossy finnish it's not durable.


Edit.....Strip your forms the following day and wet down the wall and tent plastic over wall (not tight to the concrete) if you really want to, but you really dont need to. Burlap is a better choice for keeping concrete moist for a cure.


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## SteelToes (Oct 5, 2010)

STL B. said:


> Dont do it, as someone else mentioned if it's not perfectly flat against the forms you'll end up with some really ugly puckers/wrinkels on your wall. It will also leave a glass smooth glossy finish, exterior concrete should'nt have that glossy finnish it's not durable.


Agreed.

STL B.

I read what you said about working with the vibrator being a best job on the site but man i still remember pulling that thing back and forth ...standing in concrete almost up to my knees 

Seriously. I still remember


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## STL B. (Oct 29, 2010)

> I read what you said about working with the vibrator being a best job on the site but man i still remember pulling that thing back and forth ...standing in concrete almost up to my knees
> 
> Seriously. I still remember


I've poured 4x more walls than flat work so I guess I blocked that from my mind......Yea it sux. But you have to admit is beats blocking or shoveling.


This is what I should've typed....


> It makes for job security and it feels nice standing up high on the forms watching everyone else dig trenches and pour flat work


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

STL B. said:


> Dont do it, as someone else mentioned if it's not perfectly flat against the forms you'll end up with some really ugly puckers/wrinkels on your wall. It will also leave a glass smooth glossy finish, exterior concrete should'nt have that glossy finnish it's not durable.
> 
> 
> Edit.....Strip your forms the following day and wet down the wall and tent plastic over wall (not tight to the concrete) if you really want to, but you really dont need to. Burlap is a better choice for keeping concrete moist for a cure.


OK, no plastic.

Speaking of plywood, I've used 23/32 sheathing (I can get the exact mumbo jumbo printed on it, if that matters), which is the cheapest stuff at Home Depot. It's pretty rough on the surface. Btw, the studs are spaced 10.5" OC. It's a similar setup to something we did before which was a little bigger and we didn't have problems with that. Anyways, let me know if you see any potential problems. I'd rather know beforehand...


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## STL B. (Oct 29, 2010)

I was a union laborer for a while and worked by the union rules......so carpenters build forms and laborers filled'um and stripped/wrecked'um. I've never built any forms, only set curb forms/tubes and ballards.

How big is your wall going to be? If it's a long wall it would prolly be cheaper to rent forms rather than buy buying 50+ sheets of plywood and using it one time.


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## Bud Cline (Mar 12, 2006)

> I've used 23/32 sheathing (I can get the exact mumbo jumbo printed on it, if that matters), *which is the cheapest stuff at Home Depot*.


And therein lies your first issue if you want to torture yourself later trying to get a decent finish on the exterior of the wall.

That plywood probably has missing knots, knot cutouts, splits, bulges, and what you can't see on the inside layers is the voids that will cause the concrete to swell on the surface as it pushes the outer lam of plywood into the hidden void.

The exact "_mumbo jumbo_" (as you refer to it) is exactly what one would look for when selecting a suitable plywood. But if you think it is mumbo jumbo then there is probably no hope to get you to change your mind about which plywood to use. So go for it, you are the one that has to be happy with the results.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

Thanks for all of the suggestions. I've put up the forms for the back of the wall, and I don't care if that's rough, so no problem there. I could get more expensive plywood for the exposed parts. But, I'm still wondering if there is something I can do to smooth out the roughness, before putting whatever as a form release. I guess I'm still looking for an answer to my original question...


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## STL B. (Oct 29, 2010)

I've seen forms that had been patched with something, maybe a 2 part epoxy. Sorry I cant give you a product name.

Even if your a pro your still going to have a little honeycomb so still consider skimming the whole wall and brushing the finish with a coarse brush or broom. I dont think it would take more than a few hours and may save you time if you if you dont have to pretty-up the face of the forms.


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## Gary in WA (Mar 11, 2009)

Sorry on the late response, I’ve been busy. I’ve stripped 2 foot walls after setting and pouring the same day, not 6 foot, read it wrong…... other than porch sidewalls and slabs on straw bales (filler), 4-5 feet tall (no snap ties with wall form on only one side).. The problem is the form restraints. In a 6’ wall, use rented forms (1-1/8” smooth veneered) plywood with cleats on the poured/set footing, snap-ties and shoes at 2’, extended snaps and whalers (Google it) at 4’ and cleats (spreaders and ties in one) on top. (That way you are not leaving a bunch of nail-holes in the form top edges). As said, much easier than spreaders and tie wire, plus the finish is better. Anything over 2’ high requires a snap-tie that sets-up overnight so when you twist the removable end off, the whole thing doesn’t just spin in place. Once they are all off, mix up some concrete powder in a burlap bag (J-bolts/nuts come in them) for a “slurry” to “sack” the wall, filling the irregularities and holes with wet mud squeezed out the sack holes while coating the wall. 

A ¼ sheet sander ( paper backward ) works well if no access to a stinger,…… Don’t forget to pitch the wall toward the dirt, if needed, and add weep holes so as not to build-up hydrostatic pressure at the inside base. Please do more “in-depth” research before the job, hope it works out well.

Gary


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

Thanks again for all of the comments. I think I'm good to go with the forms and form release. Now, I'm thinking about possible alternative to snap ties. I've posted that question in a new thread, in case anybody is interested:
http://www.diychatroom.com/f19/concrete-forms-alternative-snap-ties-109252/#post677137


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

That other thread doesn't seem to be working out---I guess I should've stayed with this one. 

So, here's the new question, which is just a thought at this point, not something that I've decided on: I was considering possible alternatives to snap ties. One thing I've seen is white PVC pipe thru the form (maybe 1" diameter tube, or so), then put something thru the pipe to tie the two sides of the form together. Later, the tubing is removed leaving a hole thru the wall, which can be patched. I can't find too much info on such an approach, but it seems like kind of a clever idea. I was wondering if anybody has any thoughts (or, better yet, experience). Thanks.


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## Bud Cline (Mar 12, 2006)

Stay with the snap-ties if that is the way you want to do it but don't go riggin' up a bunch of Rube Goldberg crap.

Besides, those pipes aren't coming out once they are in there, then any patching you want to do later won't stick to the plastic and will likely create a week point in your finish product.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

Bud Cline said:


> Stay with the snap-ties if that is the way you want to do it but don't go riggin' up a bunch of Rube Goldberg crap.
> 
> Besides, those pipes aren't coming out once they are in there, then any patching you want to do later won't stick to the plastic and will likely create a week point in your finish product.


I see a lot of walls around here with holes all the way thru, so I know somebody is doing something like this. And I don't think there's any structural issue.


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## Bud Cline (Mar 12, 2006)

Go for it!


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## STL B. (Oct 29, 2010)

The bolts your talking about are refered to as "she-bolts" to tie the forms together and they are just coiled rod. I cant remember how they installed them though, I think that there is a sacrifical peices that stay in the wall...???? I remember greasing them (grease by the bucketful) I dont think a 6' wall calls for anywere near that much support though.

I agree with bud that you'll never get the pvc out of the wall. You may get a couple out but you'll have burned a full tank of curse words doing it. 

If I were you I'd find a local rental shop that carries diffrent form systems and supplys, they may have just what your looking for.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

Thanks again for the comments/suggestions.

I've now got the forms nearly completed and have decided to go with standard snap ties. But, I'm still kinda stuck on the form release issue. Several local people have told me to use motor oil or diesel, but I'd like to use something a little more environmentally friendly. I also might want to put some tile or such over it eventually, and I'm thinking the heavy-duty oil might cause problems.

I know several people suggested getting "real" form release, but I can't seem to find anything local. So, after some internet searching, I'm thinking that maybe a thick mineral oil might be a good choice. Whaddayathink?


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## jomama45 (Nov 13, 2008)

There's plenty of "enviromentally friendly" releases available, you'll probably just need to go to a local ready-mix supplier to find them. Here's one brand we use quite often:



http://www.wrmeadows.com/wrm00006.htm


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## pls8xx (May 2, 2009)

Jeremy Hillary Boob said:


> I see a lot of walls around here with holes all the way thru, so I know somebody is doing something like this. And I don't think there's any structural issue.



I've done a lot of this type wall. The form system works well for home owners who can do the job in stages, using the bolt together forms for repeated sections of wall.

While higher walls can be built with the type forms I use, they work best on walls no taller than 32". Most diy homeowners would be smart to leave tall walls to contractors.

For walls under 4 ft high, my walls were poured 5.5" thick. The pvc spacer tubes are easy to tap out of the completed wall. Before assembling the forms I coat the pvc spacers with full strength mop-n-glow and let it dry. As a mater of fact, when the above is done the spacer can be removed and replaced with a longer piece, a good method for putting water or electrical conduit through the wall.

Below are some forms partially assembled forms ...


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

pls8xx said:


> I've done a lot of this type wall. The form system works well for home owners who can do the job in stages, using the bolt together forms for repeated sections of wall.
> 
> While higher walls can be built with the type forms I use, they work best on walls no taller than 32". Most diy homeowners would be smart to leave tall walls to contractors.
> 
> ...


Thanks for that interesting info. That's exactly what I was considering doing, and I know I'd seen some info online, but couldn't seem to track it down---I bet it's something you had posted previously. 

However, we're building a pretty substantial wall, and I was able to find the snap ties locally, so I'm going to go that route this time around. We also built another wall (even higher than the current one) using the same snap ties, and that worked out well, so I figure why mess with success.

So, what do you use for form release? It looks like you've painted the forms. Did you do anything in addition?


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

jomama45 said:


> There's plenty of "enviromentally friendly" releases available, you'll probably just need to go to a local ready-mix supplier to find them. Here's one brand we use quite often:
> 
> 
> 
> http://www.wrmeadows.com/wrm00006.htm


Thanks for the link. About how much does that stuff cost you, and how far does a gallon go?

The problem is finding something local, since I'm about ready to pour, and I don't want to delay any longer. I'm sure some places around here have some stuff, but a lot of them seem to only deal with contractors.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

The forms are done, and I'm (finally) hoping to get it poured in the next day or two. I've used high strength snap ties and I used DuoGard II as the form release (almost no odor or mess).

I'm going to have an experienced concrete guy help with the pour, but I have a question about vibrating the concrete. I've read several things about how to properly vibrate concrete, and the official info goes something like this: 
Insert the vibrator and let it drop of it's own accord to the proper depth. Leave it there for 5 to 15 seconds, then pull it up at a rate of about 4 seconds per foot. Also, don't drag the vibrator thru the concrete and don't use it to move concrete horizontally.

Here is one place where you can find this info (there are lots of others that say basically the same thing):
http://www.concreteconstruction.net/Images/Vibrating Concrete in Wall Forms_tcm45-342880.pdf

However, when I go on YouTube and look at examples of people actually vibrating concrete, they seem to go a lot faster than recommended. That is, they lower the vibrator head down, leave it there for a couple of seconds, and then pull it up a lot faster than 4 seconds per foot. So, I'm just wondering what is the proper technique. Thanks.


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## STL B. (Oct 29, 2010)

I was taught to let it drop on it's own and then to pull it out at the same rate, with no stop at the bottom. Over lapping the pattern by a third on the next plunge. Horizonal ?.......yea you should try not to do that.....BUT if you just need to fill in a corner or at the end of the form go ahead and dick it, just dont try to move concrete several feet and dont over do it. I would say that for the size of your wall a 1"-1.25" dia. tip or "dick" should work fine. 

Plan on having someone help with the vibrator power switch, It can be a handfull sometimes for one man. It's important that you shut it down when not in use or it will over heat, pulling it out of the mix and droping it in a foot away is fine just dont stand there and let it humm.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

STL B. said:


> I was taught to let it drop on it's own and then to pull it out at the same rate, with no stop at the bottom. Over lapping the pattern by a third on the next plunge. Horizonal ?.......yea you should try not to do that.....BUT if you just need to fill in a corner or at the end of the form go ahead and dick it, just dont try to move concrete several feet and dont over do it. I would say that for the size of your wall a 1"-1.25" dia. tip or "dick" should work fine.
> 
> Plan on having someone help with the vibrator power switch, It can be a handfull sometimes for one man. It's important that you shut it down when not in use or it will over heat, pulling it out of the mix and droping it in a foot away is fine just dont stand there and let it humm.


That seems to be the way that I see people using them online. I think the only one I can rent here is about 2" diameter, so I hope that's not a problem.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

STL B. said:


> I was taught to let it drop on it's own and then to pull it out at the same rate, with no stop at the bottom. Over lapping the pattern by a third on the next plunge. Horizonal ?.......yea you should try not to do that.....BUT if you just need to fill in a corner or at the end of the form go ahead and dick it, just dont try to move concrete several feet and dont over do it. I would say that for the size of your wall a 1"-1.25" dia. tip or "dick" should work fine.
> 
> Plan on having someone help with the vibrator power switch, It can be a handfull sometimes for one man. It's important that you shut it down when not in use or it will over heat, pulling it out of the mix and droping it in a foot away is fine just dont stand there and let it humm.


Btw, I just found another place that rents them and has a 1" diameter and 1.5" diameter. It looks like the 1" diameter should work (according to their specs), and it's a lot lighter weight.

Here's another unrelated questions... Do we need to pump the concrete or can we just drop it from the chute? Access is sufficient, so it seems to me that no pump is necessary. Is that correct?


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## jomama45 (Nov 13, 2008)

STL B. said:


> I was taught to let it drop on it's own and then to pull it out at the same rate, with no stop at the bottom. Over lapping the pattern by a third on the next plunge. Horizonal ?.......yea you should try not to do that.....BUT if you just need to fill in a corner or at the end of the form go ahead and dick it, just dont try to move concrete several feet and dont over do it. I would say that for the size of your wall a 1"-1.25" dia. tip or "dick" should work fine.
> 
> Plan on having someone help with the vibrator power switch, It can be a handfull sometimes for one man. It's important that you shut it down when not in use or it will over heat, pulling it out of the mix and droping it in a foot away is fine just dont stand there and let it humm.


Excellent advise IMO.......... :thumbup:

I've never noticed a benefit from letting it sit in the bottom of the form. I'd also agree with the 1-1.25" head for your situation with about a 4" slump concrete. Anything more will likely just cause more problems than good.

Good luck with the pour............


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## jomama45 (Nov 13, 2008)

Jeremy Hillary Boob said:


> Btw, I just found another place that rents them and has a 1" diameter and 1.5" diameter. It looks like the 1" diameter should work (according to their specs), and it's a lot lighter weight.
> 
> It depends alot on the motor (the main body) size. A small cordless vibrator with a 1" head won't really do much, but a sizable motor with 1" is sufficient.
> 
> ...


You can certainly chute it IF the 6' tall wall isn't too far out of the ground. With a front discharge truck, I wouldn't expect them to reach anymore than 4' high w/o a real wet concrete and no chutes on. 2-3' is much easier fro them to reach, vertically speaking.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

jomama45 said:


> Excellent advise IMO.......... :thumbup:
> 
> I've never noticed a benefit from letting it sit in the bottom of the form. I'd also agree with the 1-1.25" head for your situation with about a 4" slump concrete. Anything more will likely just cause more problems than good.
> 
> Good luck with the pour............


Here's the stats on the vibrator:

Weight: 20 lbs.
Frequency: 50-60 hz
Capacity: 8 cu. yd.
Compaction Area: up to 16 in. dia.
Motor: 1.3 hp
Power: electric - 115 volt
Electrical Draw: 9 amps
Electrical requirement: 1,100 watts
Head Diameter: 1 in.
Available Whips: 6.5 ft.


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## jomama45 (Nov 13, 2008)

Jeremy Hillary Boob said:


> Here's the stats on the vibrator:
> 
> Weight: 20 lbs.
> Frequency: 50-60 hz
> ...




Exactly what you need IMO...... :thumbsup:


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

It seems my usual concrete guy is extremely busy. Any suggestions as to where I might look to find a reliable person for something like this? I'd really like to get it poured soon.

In any case, here are a couple of pictures.


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## Bud Cline (Mar 12, 2006)

Any rain in the forecast?

Form release would also serve as a preservative to keep the plywood from delaminating maybe. While you are waiting for someone to come along to help.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

Bud Cline said:


> Any rain in the forecast?
> 
> Form release would also serve as a preservative to keep the plywood from delaminating maybe. While you are waiting for someone to come along to help.


I did slather the inside with form release, but nothing on the outside. Anyways, we had fog and a very light drizzle this morning and might have similar weather tomorrow, but no appreciable rain will fall until October. I'm fairly certain it'll be done by then...


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## STL B. (Oct 29, 2010)

Your forms look good and strong. Where are you going to have the truck parked at for the off load, or are you going to get a truck with a conveyer ? I ask because it seems a little tall for a truck to chute it in, you may need someone with a come-along or shovel to help things along.

I'd look for another concrete guy if your regular hand cant make 2hrs. in his busy schedule to earn money. You could call local contracters and get bids or.........and I know people will piss and moan over this but I dont care..........You could find a building thats going up localy and hit up the nearest taverns at around 4pm go in for a drink and look for the guys that are wearing concrete on their hair,sunglasses,clothes and boots. Those guys make good money mon.-fri. and $200-$300 in tax free cash will get them on a sat. I only say that cause you've got all of the work done already and a contractor has to make it worth their time.

p.s. It doesnt look like your forms are very well oiled it may just be the photos but you may want to think about covering the forms with plastic to keep rain form washing all the form oil off.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

STL B. said:


> Your forms look good and strong. Where are you going to have the truck parked at for the off load, or are you going to get a truck with a conveyer ? I ask because it seems a little tall for a truck to chute it in, you may need someone with a come-along or shovel to help things along.
> 
> I'd look for another concrete guy if your regular hand cant make 2hrs. in his busy schedule to earn money. You could call local contracters and get bids or.........and I know people will piss and moan over this but I dont care..........You could find a building thats going up localy and hit up the nearest taverns at around 4pm go in for a drink and look for the guys that are wearing concrete on their hair,sunglasses,clothes and boots. Those guys make good money mon.-fri. and $200-$300 in tax free cash will get them on a sat. I only say that cause you've got all of the work done already and a contractor has to make it worth their time.
> 
> p.s. It doesnt look like your forms are very well oiled it may just be the photos but you may want to think about covering the forms with plastic to keep rain form washing all the form oil off.


Thanks for all the comments/suggestions.

I was debating (with some input from my handyman neighbor) whether to try to use a chute or pay for a pump. I think I'll go with the pump, mostly because I'm afraid that with a chute, we won't be able to avoid some spillage over the back.

I did find one guy who would do it, but he wanted $400 which seems too high. Like you, I'm thinking that $200-$300 is about right (and, with a pump, that'll be at least $200 more). Hopefully, I'll get it all settled this weekend and get it poured early next week---for some strange reason I find it a lot more stressful with the thing just sitting there than when I was actually working on it.

As for the form "oil", I used this stuff
http://www.wrmeadows.com/wrm00006.htm
which is water-based and goes on almost like water. Supposedly, the stuff soaks into the wood, then reacts with the concrete to prevent adhesion. The best part about it is that it has almost no odor and cleans up easily with soap and water. I've heard good things about it, and I guess I'll soon find out just how well it works. And, yes, the forms certainly do look dry, and they feel dry too.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

*to pump or not to pump, that is the question...*

I seem to be getting some conflicting advice from my usually-reliable sources as to whether I'll need a pump to effectively get the concrete in this wall or not. The framing is 6 feet high and access is pretty good---we used a chute for the base. The truck might be 15 to 18 feet away at the farthest point, and the ground nearby is fairly level, but might slope away about a foot. So, the worst case would be an effective height of about 7 feet and about an 18 foot chute. Is that going to present any difficulties? 

Also, I'm a bit concerned about some concrete missing its mark and ending up behind the wall if we don't use a pump. Of course, it's a little cheaper if I don't need a pump, but I want it to go smoothly more than I want to save a couple hundred dollars. Thanks.


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## jomama45 (Nov 13, 2008)

I see no way that you'll be able to pour directly from the truck with those parameters, other than a 8"+ slump (will be VERY trying on your formwork, especially combined with a vibrator) and at least one person pulling the concrete down the chute. Also, I don't believe even the newest front discharge trucks here will reach over 6', even with the knuckel under the chutes flipped up. I'd either pump or convey in this situation.


BTW, considering the amount of thought & effort you've put into the well formed wall so far, why not attempt to pour the wall yourself? I know it may seem intimidating when the truck shows up, but there really isn't much involved in finishing the top of a wall.


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## tpolk (Nov 7, 2009)

check and recheck your bracing especially outside corners they will open up like ripe fruit, I know from fixing mine on a commercial job many moons ago


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

jomama45 said:


> I see no way that you'll be able to pour directly from the truck with those parameters, other than a 8"+ slump (will be VERY trying on your formwork, especially combined with a vibrator) and at least one person pulling the concrete down the chute. Also, I don't believe even the newest front discharge trucks here will reach over 6', even with the knuckel under the chutes flipped up. I'd either pump or convey in this situation.
> 
> 
> BTW, considering the amount of thought & effort you've put into the well formed wall so far, why not attempt to pour the wall yourself? I know it may seem intimidating when the truck shows up, but there really isn't much involved in finishing the top of a wall.


This morning I called the pump operator just to check on his availability, and it turned out that he was in the middle of a big job and they had concrete available (actually, marginally stronger than what I requested) and he could be at my place in a couple hours, etc. Anyways, I went ahead and poured it using the pump and it went smoothly. It probably only took about 20 minutes to get the concrete into the form.

The only glitch was that the vibrator I rented seemed a bit too wimpy for the concrete, and so I ended up spending a lot more time vibrating than I might have otherwise. I'm still not sure it did a great job---I hope there's no "honeycomb" when I pull off the forms. Other than that, it was pretty warm (about 78 degrees) and I probably should have worked a little faster to level off the surface, since it ended up slightly wavy in a couple spots. Fortunately, I don't think that'll be too noticeable. All in all, it worked out well, I think. 

Considering how much time went into digging, bending rebar, and building the form, the pour was almost anticlimactic...


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## gstuartw (Jul 12, 2011)

Reading this has been like a suspense novel . Be sure to keep us posted and include pictures. I wish I had the time to try this myself. I'm needing a retaining wall will run 40' from corner to end in two directions. 48" high down to 10". I'll most likely use Versa-Lock blocks rather than concrete.

BTW There seem to be quite a few members experienced in concrete weighing in on this subject. I'd appreciate anyone chiming in on my post http://www.diychatroom.com/f19/extending-driveway-111160/ if you would.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

gstuartw said:


> Reading this has been like a suspense novel . Be sure to keep us posted and include pictures. I wish I had the time to try this myself. I'm needing a retaining wall will run 40' from corner to end in two directions. 48" high down to 10". I'll most likely use Versa-Lock blocks rather than concrete.
> 
> BTW There seem to be quite a few members experienced in concrete weighing in on this subject. I'd appreciate anyone chiming in on my post http://www.diychatroom.com/f19/extending-driveway-111160/ if you would.


I'll definitely post some pictures, but I want to let the suspense build a little longer...

Actually, I plan to keep the forms on for quite a while. Surprisingly, I can flood the top, and the forms keep the water there for a long time (the wall is 5' 9" high while the forms are 6' high). I've got a plastic sheet draped over the top. All that should keep things nice and moist so it can cure properly, and it doesn't take much water.


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## STL B. (Oct 29, 2010)

Way to go, not to bad huh?



> The only glitch was that the vibrator I rented seemed a bit too wimpy for the concrete, and so I ended up spending a lot more time vibrating than I might have otherwise.


It likely wasnt the vibrator I'd bet the concrete was blowing-up (setting up) when it got to you.




> I probably should have worked a little faster to level off the surface, since it ended up slightly wavy in a couple spots.


Mix up some slurry/skim coat and level it out if it bothers you, the sooner the better



> Actually, I plan to keep the forms on for quite a while. Surprisingly, I can flood the top, and the forms keep the water there for a long time (the wall is 5' 9" high while the forms are 6' high). I've got a plastic sheet draped over the top. All that should keep things nice and moist so it can cure properly, and it doesn't take much water.


It wont hurt anything but I dont think there's much to gain by doing this. If you do have honeycomb that you want to fill the skimcoat/patch will adhere better when the pour is "green" or fresh, plus if everything looks good and no patching is needed you can water down the face of the wall to bring out a nice bone white color. If it were me I'd strip-um tommorow and stick a fork in it.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

STL B. said:


> Way to go, not to bad huh?


No, not bad at all. Anybody who is considering doing this, I'd say you should have no fear. It is kind of intimidating when the truck and pump show up, but as long as everything is ready to go and you have a few extra hands around (I had a neighbor and my teenage son, but I could've done it without either of them in a pinch), you won't have any problems. The pump guys do all of the hard work. Vibrating is not difficult. And, as was pointed out, there's not much to finishing the top of a wall. My only advice is to work quickly, just in case the concrete decides to firm up early.



STL B. said:


> It likely wasnt the vibrator I'd bet the concrete was blowing-up (setting up) when it got to you.


Yes, the more I think about it, the more I think you are exactly right. The concrete was sorta like a more gelatinous mass than the concrete we've gotten delivered in the past (this was my 5th time to get concrete delivered). It seemed to fill in OK as it was pumped into the form, but it definitely wasn't keen on flowing horizontally. I'm still surprised at how quickly it set up. Anyways, all's well that ends well...


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## concretemasonry (Oct 10, 2006)

Get the forms off now, knock off and projections. Then rub the wall with a stone to spread a thin coat of sand and cement that will cure with the rest of the wall. The sooner, the better, since any projections can be removed easier and holes/voids can be filled and everything bonds together better.

This was a common procatice for highway bridge piers and exposed abutments to provide an even color surface that can be naturally be kept clean in rains (unless surface water in run over it).

Dick


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

*To cure or not to cure? That is the question...*



concretemasonry said:


> Get the forms off now, knock off and projections. Then rub the wall with a stone to spread a thin coat of sand and cement that will cure with the rest of the wall. The sooner, the better, since any projections can be removed easier and holes/voids can be filled and everything bonds together better.
> 
> This was a common procatice for highway bridge piers and exposed abutments to provide an even color surface that can be naturally be kept clean in rains (unless surface water in run over it).
> 
> Dick


Every official source that I read says you need to keep it moist for 28 days to achieve the rated strength (in the case of my wall, 4000 psi). If it's not moist-cured at all, the strength will only be about 55% of the potential. You can find this info lots of places, but the graph on the 3rd page of this document is pretty clear:
http://www.tkproducts.com/Curing Concrete.PDF

Based on the official info, it seems to me like it would be important to properly cure the concrete for at least 7 to 10 days by keeping the surface constantly moist. That amount of time will get you about 90% of the strength. However, most of the experienced concrete people I talk to around here---as well as people on forums like this---don't take this step seriously. In fact, virtually all of them tell me that, at best, it's a waste of time and, at worst, it might even do some harm. I'm confused (as usual).

So, what's the right answer, and why? Thanks.


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## STL B. (Oct 29, 2010)

The truth is that your concrete wont reach a full cure for many moons, moist or not. And truth be told your wall doesnt need to be very strong, it's not supporting anything.

The spec. for concrete to reach full strenth in 28 days is a safe guard, most concrete will reach 90%-95% within days.

I've poured large supporting walls 30'+ tall and they get stripped the next day and the mix always passes the test.


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## STL B. (Oct 29, 2010)

There's a PBS documentary about a bridge that built over the miss. river at alton il. 

In this documentary they poured the piers and cured them under wet burlap for weeks, but the concrete never tested out to spec. So dozens of laborers had the privilage of chipping out an entire lift 10'-15' of weak concrete. 

Point being the mix is more important than the cure.................and in your case I dont think either is a deal breaker


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## concretemasonry (Oct 10, 2006)

Dr. Jeremy -

The 28 day cure is just a standard used for curing samples in a laboratory (by other Drs.) to deterimine the specific strength for a specific mix design. Other conditions will create higher strengths much faster.

The 28 day myth is just that. Other factors, such as placement and site curing are what take precendence on the finished project. - I hope you did not dump to full height when you had a pump avaiable, because it probably would have been better to do it in lifts and not worry about it flowing horizontally. All you do is vibrate through the most recent layer to joine the two layers of plastic concrete.

All too often people split the hairs too finely about vibration frequency, when the method of use is more important. - From a person that has been a concrete inspector and a bridge inspector for the local DOT.

Normally mixes are intentionally over designed because of the variabilities in the sample taking, curing, transportation and testing errors. Even a guy on the job site making a test cylinder can make or pump up a sample. That it is why it is cheaper for a supplier to add a little extra cement in the mix design for a cushion and avoid any disputes they have no control over..

Dick


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

concretemasonry said:


> Dr. Jeremy -
> 
> The 28 day cure is just a standard used for curing samples in a laboratory (by other Drs.) to deterimine the specific strength for a specific mix design. Other conditions will create higher strengths much faster.
> 
> ...


Thanks for the info. 

I do play a doctor in real life, which means that I'm naturally more dense than the average human being. So please bear with me a little longer...

We poured the wall in 2 lifts. The flow issue only came up because I'd placed a couple of these "column base" things on the top:
http://www.strongtie.com/products/connectors/LCB-CB.asp
It would've made things easier if the concrete had been a little more cooperative in flowing around those things. In any case, it wasn't a major deal, just not quite what I expected.

You say that 28 days is a myth and you say that "other factors" are more important. Just for future reference, what are the critical issues wrt "placement" and "site curing"?

Finally, even if other factors are more important, I can't see any harm in letting it sit as is for a couple weeks. I'm not in a hurry and the forms are definitely holding in a lot of moisture, which has got to be a good thing.


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## STL B. (Oct 29, 2010)

Is your name really Dr. Boob ? If it is I hope your a plastic surgen


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## Bud Cline (Mar 12, 2006)

PhD = Probable heavy Drinker ???

PhD = Permanent head Damage ???

PhD = ____________________ ???

Fill in the blank.


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## STL B. (Oct 29, 2010)

> PhD = Probable heavy Drinker


If thats the case I'd be a doctor also............I'll be a OBGYN.


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## concretemasonry (Oct 10, 2006)

Doctor -

If you are really a doctor, you should know how to research thoroughly and properly to understand what the numbers are and what they mean. Then you refer it to a specialist if you are not capable to really make the proper decisions.

Nit picking does not work with engineering or construction, but does fool some people.

The 28 days is from an ASTM specification for concrete mix design (1,2,7 and 60 days tests are also done) and verification of the STRENGTH in the lab conditions OR testing of cylinders made at various points in construction from the cylinders taken on the job site and cured in attempt to come close to the "design" strength. Even then, some cylinders that are taken are handled/cured/transported/tested properly and the results are tossed out like "the baby and the bath water". Normally, site cast cylinders break at much higher strength than the design and in some cases, an engineer familiar with the projects may call for a review. Many testing labs routinely take digital photos of all cylinder breaks for future reference.

Flooding the top with water is not a good prescription and keeping the forms on too long can result in temperatures of the concrete to be too high for proper curing. There are many recommendations for keeping the wall under proper conditions and still being able to correct superficial placement problems. It also allows a good look to see if there are any real structural plcement problems that can be corrected early instead of allowing the cancer to grow.

Without any inspection or samples, you are left to flounder in your "bath water".

Did you have a professional design it or have any inspection of the placement and preparation of the samples for verification.

You structure looks to be grossly over designed for what appears to be the intended purpose. Nothing wrong was done and it will stand for a long, long time so don't worry any more.

Dick


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## Bud Cline (Mar 12, 2006)

Isn't a *PhD* a "*doctor of philosophy*"? 
Bid deal.

*philosophy: *the rational investigation of the truths and principles of being, knowledge, or conduct.

Doesn't say anything about rationally understanding any of the principles of the building trades.


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## kwikfishron (Mar 11, 2010)

concretemasonry said:


> Doctor -
> 
> If you are really a doctor


http://en.wikipedia.org/wiki/Jeremy_Hilary_Boob


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## Bud Cline (Mar 12, 2006)

There ya go.

I thought that sounded familiar.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

STL B. said:


> Is your name really Dr. Boob ? If it is I hope your a plastic surgen


I am a PhD, but not Dr. Boob, although some of my colleagues would probably argue that the name fits...

When I graduated from college, I got a BS degree. Everybody knows what BS stands for. Then I went to graduate school and got an MS degree, which stands for "More of the Same". Finally, I got my PhD, which, of course, stands for "Piled higher and Deeper". So, now you know the rest of the story...


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

concretemasonry said:


> Doctor -
> 
> If you are really a doctor, you should know how to research thoroughly and properly to understand what the numbers are and what they mean. Then you refer it to a specialist if you are not capable to really make the proper decisions.
> 
> ...


Thanks again for the info.

Actually, I'm not worried, and I believe that wall will be here for many generations after I'm gone. But, I figure that since the deed is done, and I have the luxury of time, I just as well try to maximize the strength. It's more like a science project than an engineering project at this point.

As I mentioned before, I realize that a lot of professionals don't put much stock in curing concrete. But for an amateur like me, it's confusing to read things like this
http://www.nrmca.org/aboutconcrete/cips/11p.pdf
which emphasizes the importance of curing concrete. It seems t me that the NRMCA is probably a pretty reputable organization and I can't see why they would have any incentive to make the process more difficult than it needs to be.

Anyways, I really do appreciate all of the comments. I'm just trying to understand a little more about the process.


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## concretemasonry (Oct 10, 2006)

Jeremy -

Here in MN a contractor will remove the forms as soon as possible due to current tempeatures ( 03 10 days ago and a week or so of 90 to 100F with high humidity) to avoid overheating and be able to provide moisture and cooling as necessary. When the aggregate finall warms up that compounds the problem. Some even order concrete with ice or iced water to prevent curing to fast. I think they are still pumping brine through the embedded pipes for control of the concrete curing after many years of placement.

It is good to see you have luxury of using you project as an unmonitored experiment and learning experience.

By the way, I have been a concrete inspector and bridge inspection before getting my Bachelor's and Masters degrees, 40 years experience and 3 international Honorary Doctor's degrees (for whatever they are worth) that just look good on the wall.

Just keep poking around, put things in perspective, learn and share your results.

Dick


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

concretemasonry said:


> Jeremy -
> 
> Here in MN a contractor will remove the forms as soon as possible due to current tempeatures ( 03 10 days ago and a week or so of 90 to 100F with high humidity) to avoid overheating and be able to provide moisture and cooling as necessary. When the aggregate finall warms up that compounds the problem. Some even order concrete with ice or iced water to prevent curing to fast. I think they are still pumping brine through the embedded pipes for control of the concrete curing after many years of placement.
> 
> ...


It's great that someone with your knowledge and experience is willing to post to a group like this. Your perspective is extremely valuable, especially for someone like me who is trying to do something well outside my area of expertise.

It'll probably be a week or two before I get a chance to do any more work on the "great wall", but when I do I'll post again, including some pictures.

Btw, I spent most of my first 20 years in Iowa, so I know all about those 100 degree (plus) temps with 90% (plus) humidity. I vividly remember high school football practice on one of those kind of days, when the guy next to me had a heat stroke.

Fortunately, we don't get that kind of weather around here---it rarely gets above 80 degrees and when it does, I'll drive 15 miles to the beach and go fish in the surf until the sun goes down.


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## Jeremy Hillary Boob PhD (Nov 11, 2008)

The continuing story...

Three days after pouring (i.e., last Thursday), I had some time and some extra help, so I decided to take advantage of the situation, and I started pulling the forms. The forms didn't stick at all, but it still took a while, due mostly to my inexperience. Then my brother was here for several days, so I'm just now getting back to it. 

I've patched the snap tie holes and smeared Thoroseal on the backside. All that's left is drainage (perforated pipe, gravel, cloth) and filling in the dirt.

In the attached picture, you can see the wavy top. That won't be too noticeable, since we plan to have ivy growing over the top. I also posted a couple of close-up pictures, one of which is about the worst spots wrt pin holes, and the other is fairly typical. 

Overall, I think it turned out pretty OK.


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## jomama45 (Nov 13, 2008)

Looks good to me, nice job.......... :thumbsup:


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