# Removing dust from holes drilled in concrete



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

I need to install a bunch of threaded rods in concrete and I'm going to use epoxy (Simpson Set-XP, to be precise). The recommendation is to use a nylon brush and compressed air---at least 80 psi, for a total of at least 8 seconds per hole. I've got the brush, but I don't have an air compressor and would prefer not to buy one. I'm going to have at least 50 holes (5/8" diameter, 4+ inches deep) to deal with.

Is there a reasonable alternative to an air compressor? If not, is there a relatively cheap air compressor that you would recommend? Thanks.


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## grizzzlle (Jan 27, 2013)

Can you borrow one from a buddy?


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## Hardway (Dec 28, 2011)

Rent one!


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## oh'mike (Sep 18, 2009)

Use the exhaust port on your vacuum cleaner ---neck down the hose to a small section of tubing or pipe----


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## grizzzlle (Jan 27, 2013)

Can I ask what the rod will be holding down? Would red heads work?


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## joecaption (Nov 30, 2011)

I use a shop vac to suck it out, hate seeing dust blown up in the air everywhere.


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

Hardway said:


> Rent one!


Unfortunately, I can't do them all at once, so I'd have to rent it several times, and just as well buy one...


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

oh'mike said:


> Use the exhaust port on your vacuum cleaner ---neck down the hose to a small section of tubing or pipe----


This sounds like a possibility. The good old shop vac (or leaf blower) could generate a lot of pressure, if I can rig up the right sort of nozzle. One requirement is that the "compressed air nozzle must reach the bottom of the hole", so it's got to be something about 6 inches long and less than 5/8" diameter.


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

grizzzlle said:


> Can I ask what the rod will be holding down? Would red heads work?


This is for a "seismic retrofit" on my house. For some of the rods, pullout is an issue, and those definitely need to be epoxied. So, I figured I just as well do the same thing for all of them. If you're interested, see the 7:35 mark of this video for a good illustration of what I'm doing:
http://www.youtube.com/watch?v=d91_62_3A1w&list=PL0C5802141ACD3CD5


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## Maintenance 6 (Feb 26, 2008)

Canned air like they use to blow out electronics?


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## TheEplumber (Jul 20, 2010)

Maintenance 6 said:


> Canned air like they use to blow out electronics?


Could go bigger and rent an oxy bottle from a welding supply shop


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## SeniorSitizen (Sep 10, 2012)

Use the vacuum next to the drill all the while you are drilling. Negative pressure there beats positive nearly every time when drilling and there will be very little residue in the hole when finished.


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## epson (Jul 28, 2010)

Jeremy Hillary Boob said:


> Is there a reasonable alternative to an air compressor? If not, is there a relatively cheap air compressor that you would recommend? Thanks.


I have always used one of these:


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## redman88 (Oct 5, 2012)

go to your local tool store, any kind and get a compressor you will be glad you did. so many other uses for it.


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## ddawg16 (Aug 15, 2011)

I went through the same thing....










Use a shop vac to 'suck' up as much as you can....if you take a real small hose....say 1/4" poly tubing like you use for the water supply for the ice maker...put one end up in the hose of the vac...other down the hole...it will get most of it....

Then take the same hose and use the exhaust port of your shop vac.....if you cup your hand over the exhaust..push the hose through your fingers...quite a bit of air comes out....

Warning....you can get a good puff of dust out of that hole....it's messy.

You know you have it cleaned out when you drop the rod in there and you get a nice 'clink' sound. If it's a 'thud', you still have dust down there.


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

Thanks for all of the suggestions. I finally decided to bite the bullet and get a cheapo air compressor from Harbor Freight. I'm glad I did. Even the holes that I thought were thoroughly cleaned out puffed a significant amount of dust when hit with 80 psi air. The down side was that I could only do a couple of holes, then I had to wait two minutes or so for the air tank to recharge. Since I was scrunched up in a narrow crawl space, I'm sure it seemed a lot longer than it really was.

Anyways, I'll try to remember to post some pictures once the epoxy dries and I get everything bolted together.


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## jomama45 (Nov 13, 2008)

You really should be using a wire "pipe cleaner" brush in the holes as well, as it's less important to get the bottom of the hole clean as it is the sides. Typically, the process is drill, blow out, brush, blow, brush, blow, and the quickest way is to get the brushes that accept 1/8" pipe thread, and run them in your drill.............


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

jomama45 said:


> You really should be using a wire "pipe cleaner" brush in the holes as well, as it's less important to get the bottom of the hole clean as it is the sides. Typically, the process is drill, blow out, brush, blow, brush, blow, and the quickest way is to get the brushes that accept 1/8" pipe thread, and run them in your drill.............


Thanks for the comment. And, yes, that's basically the process that Simpson recommends:

1) Compressed air, at least 80 psi for at least 4 seconds
2) Nylon "bottle" brush, in and out at least 4 times
3) Compressed air again, 80 psi minimum, 4 seconds minimum

So, that's the essentially what I did. The brush I used was a tight-fitting nylon bottle-type brush designed for the purpose, and I used it more than 4 times per hole, twisting as I inserted it and pulled it out.

Because of the temperature, I've had to wait 72 hours for the epoxy to set. That time is up tomorrow afternoon, so probably by the day after I'll be able to finish off this first phase of the project. I'll post some pictures when it's done.


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## ddawg16 (Aug 15, 2011)

Did you buy the double barrel epoxy gun or just rent it?

And....Isn't that epoxy expensive? And careful what you get it on....it WON'T come off....


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## Anti-wingnut (Oct 18, 2009)

TheEplumber said:


> Could go bigger and rent an oxy bottle from a welding supply shop


Oxygen should never be used for anything it was not designed for. The use of highly compressed air gas, especially oxygen, as a substitute for lower pressure compressed air is potentially very dangerous.

There are several substances that can spontaneously explode or ignite with pure high pressure oxygen.


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

ddawg16 said:


> Did you buy the double barrel epoxy gun or just rent it?
> 
> And....Isn't that epoxy expensive? And careful what you get it on....it WON'T come off....


Good questions. Yes, I bought the double barrel epoxy gun (the smaller one, for 22 oz tubes). It's outrageously expensive, but on the upside, it works pretty well, given that the epoxy is extremely stiff stuff. Of course, the epoxy itself is expensive too. Now I figure that I have to epoxy a lot of bolts into place to make it all worthwhile...

Actually, I allocated $1K for this entire job, and even after buying a good rotary hammer ($200), a cheap air compressor ($75), a fancy epoxy gun (about $65), and almost all metal parts being zmax/galvanized, I'm sure I'll still come in well under budget. It would of cost several times as much to get somebody to do it, and even more to get it done by somebody I really trust to do it right.

Btw, I've previously done quite a bit of work with epoxy (boat builder kinds of stuff mostly, but also epoxy grout---not epoxy-related concrete work). If you're interested, here are some photos where I put epoxy over a madrone slab
http://www.woodworkingtalk.com/f8/epoxy-madrone-slab-17529/
and here's some pictures of some of my epoxy grout work
http://www.johnbridge.com/vbulletin/showthread.php?t=79843&page=4

Anyways, you definitely don't want to get epoxy on your bare skin. It's a "sensitizing" agent (like poison oak, for example). You might have no problem the first time (or 2 ,or 3, or...) that uncured epoxy gets on your skin, but at some point, you're likely to be sensitized. After that happens, you'll have a nasty reaction whenever you touch it, and maybe even when you're just in the same room with uncured epoxy. So, it's best not to let things get to that point.


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

Thanks to all of the helpful responses here, I've finally made some progress on my seismic retrofit. I've started a different thread for that info---if you're interested, point your browser here:
http://www.diychatroom.com/f19/seismic-retrofit-169941/


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