As California builders, my colleagues and I are often called on to retrofit anchor bolts for sill plates to reinforce a house against earthquakes. Whenever we drill a hole for an anchor bolt, we typically use a short length of 3/8-in. dia. tubing affixed to our compressor’s blower gun to blast the dust out of the holes. This method is pretty reliable for removing the concrete dust, ensuring a clean bonding surface for the epoxies we use to anchor the bolts.
On one job, we realized after we started drilling that the tubing was at another job site. Rather than make a special trip to retrieve it, we improvised. We found a short length of 12/2 Romex wire and removed its innards except the ground wire. Then we duct-taped the wire sleeve to the blower gun. The ground wire kept the sleeve stiff enough to enter the hole, and the sleeve effectively directed the air to the bottom of the hole. This method really sends the dust flying, so be sure to wear a respirator and eye protection and to keep your head away from the hole.
Jim Brovelli, Berkeley, CA
Edited and Illustrated by Charles Miller
From Fine Homebuilding #111
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Typical "mother of invention, American Inguinity" thought process and a very good one. And, thanks for passing it on so the rest of us can use it also.
TN_P_Elm
Another method is to use a less expensive shop vacuum. Doesn't require a respirator. Even a small shop vacuum will do. Use a 1.25 hose and use your gorilla tape to affis it to your romex tubing. Viola', dust is gone. And you have a clean worksite and no problems with your breathing.
Use a vacuum OSHA has very strict rules about concrete dust.
I agree with two of the commenters, use a vacuum. Blowing out the dust so it gets everywhere is so old school. Certainly no American Ingenuity in that.
And considering that this is a retrofit, blowing dust around in a clients home doesn’t win awards...
Anyone doing work that requires an approval (ICC, etc.,) needs to read the approval to see what the required hole preparation is. I just looked at an ICC report of Hilti heavy duty expansion anchors and there is nothing about using a shop vac. On the contrary the ICC approval has blow out bulb or compressed air only.
With non-approval work, you need to think about the manufacturer’s guarantee. If some big assembly comes down, you can bet somebody is going to take a good look at how the holes were prepped. If the manufacturer can show that the holes weren’t clean, you can only hope your liability insurance is paid up.
If dust in the air is a concern, wear a respirator.
The question to ask yourself is how do you know you are getting the hole clean when you use a shop vacuum. My guess is that if you followed up with air pressure, you’d get a face full of dust – not as much as if you used air from the start, but still.
Thinking about comparing a shop vacuum to air pressure, if I’m cleaning up a tool for repair or alteration, I always need to use air. The shop vacuum just don’t cut the mustard. I bet the same goes for a drilled hole in concrete.
I once forgot nails on a trim molding job, so I used a bunch of leftover pop-rivet stems that I stuck in my pocket for later recycling. Worked out great and I didn't have to go to the Lowes a few miles down the road.
Seems like a combo of blown air and a shop vac would solve all problems.
Use the blown air to clean out the hole WHILE having a shop vac just at the hole to capture all/most of the dust being blown out.
If you can regulate the amount of blown air (start gentle and ramp up), then you are less likely to overwhelm the shop vac flow capacity.