# How to get out pvc embedded in concrete



## ESwierenga (Jun 7, 2017)

I recently made some garden box supports out of concrete. As you can see in the pictures, the installed product has a 1/2" dowel rod that extends through the structure and then anchors it in place on the ground. In order to get this hole I put a length of pvc through the middle while pouring the concrete. 

The problem is that I can't get some of the pvc pieces out of the middle. Most of them I had no problem with. I think this batch I let sit to cure a few days longer, not realizing this would be an issue. I tried drilling it out and that kind of worked but it not very well, and it would be difficult to drill through the entire length. It also was ruining the bit because it kept catching on the side of the concrete. I tried hammering it out with a metal pipe but I ended up bending the pipe a bit and creating a big fat ring on the impacted end. 
Could a heat gun be helpful in pulling the pvc out? 

I understand that concrete expands and contracts in different temperatures/humidity. In order to loosen the grip on the pvc pipe would it be helpful to bring it to a cool/warm or moist/dry place? What would be the right combination? 

Thank you all!!:glasses:


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## de-nagorg (Feb 23, 2014)

PVC will dissolve with a strong enough solvent.

Search for a solvent recommended for that.

For future reference, a release agent on your concrete forms will prevent this fiasco.

My preferred release agent is PAM, the cooking spray, bio-degradable, Cheap, and available .

As for the problem now, you might try heating the entire assembly, a tub of boiling water, immerse the assembly, let it all warm up, then remove the assembly, use a garden hose to run cold water through the piping, and hope that it shrinks first, and releases.

Keep in mind that concrete submitted to these extreme differences in temperature too quickly, will cause it to SPALL, and possibly crack.


ED


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## ClarenceBauer (Mar 4, 2005)

To remove the PVC tubing use two brush coats of Mold Builder liquid latex rubber apply one maybe two coats when dry use as required when the cement cures the tubing can be removed & reused. It should be noted that the rubber can be applied in as many coats as needed. I have used many gallons for plaster reproduction it works very well.


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## ZTMAN (Feb 19, 2015)

Why do you need to remove the PVC? Cut off the excess and get a dowel rod that fits inside the PVC and use that as an anchor. Recess the rod and cap it off and you will be good.


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## Bondo (Dec 8, 2007)

ZTMAN said:


> Why do you need to remove the PVC? Cut off the excess and get a dowel rod that fits inside the PVC and use that as an anchor. Recess the rod and cap it off and you will be good.


Ayuh,..... 3/8" rebar,....

Use bigger pvc next time,....


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## CodeMatters (Aug 16, 2017)

PVC has a relatively high coefficient of thermal expansion. Capping one
end and pouring ice water into the other might contract the PVC pipe
enough to allow extraction.


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## Nealtw (Jun 22, 2017)

Most people have the tools in the yard to freeze the pipe and knock it out.


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## mathmonger (Dec 27, 2012)

I wouldn't trust a half inch dowel to hold the support in place, let alone the wood and dirt. But anybody who casts random stuff out of concrete is cool in my book. I like Bondo's suggestion with the 3/8" rebar.

I'd probably try freezing or heating it because it's an elegant solution. But I'd be surprised if it actually worked the way it does in my brain. I real life, maybe I'd throw them away and recast them. Or if you want to drill them, that might work. The cutting part of a drill bit is the tip. I don't know if banging up the sides would do much harm. Or maybe just hack at it with a cheap spade bit.


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## KHouse75 (May 14, 2008)

Boiling water will make PVC very pliable. Cap one end of the PVC and carefully pour in boiling water. Let sit for few seconds. Take a long screw driver or metal rod with a rounded end and push it or hammer it down between the pipe and the concrete. Pour out the hot water and allow 30 seconds or so for the PVC to harden back up (or pour in cool water to harden it up faster). Remove the rod or screwdriver. This should relieve enough pressure to allow you to tap it out the rest of the way.


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## t.carpenter00 (Jan 23, 2018)

Let us know if any of that works. If not, we'll start round 2.

Sent from my VS988 using Tapatalk


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## ESwierenga (Jun 7, 2017)

Thanks for all the great ideas.
I wanted to wait and update you all after I had tried some of the recommendations. 
As suggested, I did consider leaving the pvc in and slipping a 1/2" dowel through it as opposed to 3/4", but decided that would be too easily bent by the weight of the dirt. Rebar is a pretty good idea. 
I tried the method of putting boiling water in and through the pipe and then pounding the pvc out. I was pretty hopeful but unfortunately it didn't budge. 

I used a spade bit to drill through the pvc cavity and succeeded in getting most of the pvc out. There are still little shreds of pvc I'm having trouble getting out that make getting the dowel in difficult. Maybe I will be able to use the solvent idea for this. Or, I will just jam the dowel through and it won't be a problem. 

I am thinking I will stretch a snug cable around the top perimeter of each of the beds. This way the 3/4" dowel will have less opportunity to bend out at the top from the weight of the dirt. And if I break my wrist off before finishing drilling the pvc out (likely), it should hold in the 1/2" dowel as well.

I'll let you know further developments


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## ESwierenga (Jun 7, 2017)

deleted duplicate -- messed up the embed


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## ESwierenga (Jun 7, 2017)

I drilled through the next pillar. The bit was a little damaged, but I think that actually helped me out because it left the remainder in a whole piece that I was able to pull out. The dowel now slides through easily.

I think this is the method I'll be working with. In the future, I will be sure to use release agent and pound the centers out sooner. 






Thanks again everyone. :vs_cool:


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## de-nagorg (Feb 23, 2014)

Great to hear that you had success removing the stuck PVC.

A cheap can of PAM, and they won't stick again.

Is this a design of your creation, or did you find it online somewhere?

It looks interesting to make planters of my own with.



ED


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## KHouse75 (May 14, 2008)

I've seen something similar at Home Depot called Planter Wall Blocks. They are stackable as well.


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## ESwierenga (Jun 7, 2017)

It is indeed a design of my own creation, but as Khouse said, there are similar products such as the planter wall blocks. 
I like the ability to customize angles and size of the wood housing, and I also find them more aesthetically pleasing. However, if I had to do it over again I'd seriously consider buying a ready product. 

It was time consuming and because I mixed the concrete quite dry, it was annoying to pack it all down. BUT I do love how they turned out. 

Thanks again everyone. 

:vs_coffee:


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## SeniorSitizen (Sep 10, 2012)

As a release agent consider trying a test with parchment paper. I haven't had any success getting 2 part epoxy to adhere to it.


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## Nealtw (Jun 22, 2017)

I would have used a pipe sized to have a galvanized steel pipe to slide in to use for a pin. The wood dowel will be a weak spot.


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