Where can I practice drilling holes in concrete walls?
July 11, 2017 11:35 AM   Subscribe

Hi AskMe! I want to drill some holes in the solid concrete walls of my apartment to hang heavy stuff, but I've never operated a power drill in my life, much less on hardwall or masonry. I know I can go to the hardware store to rent/buy a drill, masonry bits, and eye protection, but I also want to practice a few times so I can get used to operating a drill, drilling straight holes, and what drill kickback feels like. But where would one go to practice? I'm in DC, and I have no yard.
posted by capricorn to Home & Garden (21 answers total) 3 users marked this as a favorite
Go to Home Depot and buy a couple concrete blocks. Also, is your landlord cool with this? Concrete walls can hide all sorts of expensive-to-fix things like plumbing and wiring inside them.
posted by rockindata at 11:42 AM on July 11, 2017 [2 favorites]

The drill's not going to kickback. Especially with a masonry bit.
posted by humboldt32 at 11:47 AM on July 11, 2017 [2 favorites]

Also, is your landlord cool with this? Concrete walls can hide all sorts of expensive-to-fix things like plumbing and wiring inside them.

Ah yes, should have mentioned this! Yep, building manager seemed totally unconcerned and just asked that I patch holes before moving out.
posted by capricorn at 11:57 AM on July 11, 2017

Also, as a heads-up, you'll likely need a hammer drill, not just any power drill. I tried to drill into a brick wall with a normal drill and a masonry bit, and got about 1/4" in 10 minutes. Went and got a hammer drill, and it was fully sunk in about 10 seconds. The one I have looks almost exactly the same, but has an additional setting.
posted by BevosAngryGhost at 12:08 PM on July 11, 2017 [7 favorites]

a) You won't have any trouble doing this - just keep it level - maybe get someone else off to the side to watch it doesn't drift.

b) To second BevosAngryGhost - if you don't use a hammer drill, you will succeed in making a small cone shaped divot in the wall. If you use a hammer drill, it will go in and stone dust will pour out and you will make Tim Allen type noises and then you will have a hole. Using masking tape on the bit to mark the intended depth.
posted by ftm at 12:14 PM on July 11, 2017 [8 favorites]

I suppose you could buy a brick, masonry block, etc. at the hardware store to use to practice on, or ask if you can have a free broken such item to use, but be sure to secure it well before drilling. But really I don't think you will need any practice.

A hammer drill will shake when you use it, so don't let that surprise/bother you.
posted by exogenous at 12:30 PM on July 11, 2017

Note that there are a few materials that are commonly grouped together as "concrete" or "cement" by laymen and they drill quite differently. A cinder block (concrete block) wall is much easier to drill into than a poured concrete wall. The mortar joint is even easier.

Depending on what you are hanging Tap-Cons are easier to use than most other anchors and retail packages sometimes come with both a properly sized drill bit and a driver bit. They can be put in with a light duty 3/8ths hammer drill so essentially no chance of injury.

The only thing you'd need to practice is holding the drill perpendicular to the surface and you can do that with any old chunk of wood like a piece of 2x4 or pallet.

Rent a battery operated drill unless you are setting hundreds of anchors.

Wrap some tape around the drill bit as a guide to hole depth (IE: put the tape such that the length of the exposed bit is the same as the desired hole depth). With tapcons too deep of a hole is preferable to too shallow (a shallow hole will snap the fastener).
posted by Mitheral at 12:37 PM on July 11, 2017 [4 favorites]

If you're only drilling 20 or 30 holes I would just buy a $30 corded drill (cheap corded drills are WAY more powerful than most cordless drills) and a $4 masonry bit.

Use the smallest faster and bit combination you can. Smaller holes are easier and faster to drill. Plus the amount of weight a single screw can carry is pretty amazing; Tapcon's 3/16 in diameter screw if screwed 1 inch into concrete will hold more than 600lbs.

A hammer drill will go faster, but you probably don't need one.
posted by gregr at 2:41 PM on July 11, 2017 [2 favorites]

I was nervous about this the first time as well so I drilled some practice holes in my basement behind a door where I never look anyway. Also seconding using masking tape to check intended depth.
posted by wolfr at 3:17 PM on July 11, 2017

As others have mentioned, you don't need a hammer drill, but by the end of n-holes, you'll want one. Masonry bits are a must, but they needn't be expensive. Consider them disposable. For a project of this size, a hammer drill from harbor freight is totally the right tool for the job (but for anchoring 6 posts to a concrete patio, you might want to rent a better one). I would personally rent one for any sized job. It's the right tool, but unless you're drilling holes in concrete all day long, it's not really worth having one around.

Walls of concrete are going to be way 'cleaner' to drill than like masonry blocks you buy at home depot or something. If you want a similar experience I'd buy similar grade concrete and mix it up in a tub and let it harden. They sell pretty small containers of concrete mix at most places.
posted by furnace.heart at 5:24 PM on July 11, 2017

If you want the poured concrete experience with a self poured block you have to leave the block cure for a month (and keep the block moist) for the block to start approaching a strength equal to a poured wall. Concrete only a few days old drills like cheese.
posted by Mitheral at 6:33 PM on July 11, 2017 [1 favorite]

I have driven tapcon fasteners into a variety of materials - brick, brick mortar, block, and concrete. A couple of practice shots is a good idea. Are you installing shelves, and can you use the acutal wall in a concealed place for your test? I'd recommend that. Block is cheap and easy to buy but heavy and some municipalities frown on putting blocks in the trash. Block is often softer than concrete so easier to drill.

This is not an overly difficult project, but there are some unforgiving aspects of the challenge. Here are a few things.

1. diameter of the drill is key. Buy the tapcon package with the drill bit inside or the tapcon bit in the right diameter. Wrong bit diameter and there will be either no way to drive the fasteners or no holding power.

2. hammer drill is recommended for more than two holes, and a must for hard concrete. Cheap plug in drill or rental is fine. You do not need a proper SDS thing, simple hammer drill is OK.

3. Definitely drill slightly deeper than the depth of the fastener. When driving a tapcon, if the tapcon fastener (screw) bottoms out in the hole before the head pulls tight at the surface, it will continue to spin and become an auger, stripping out and widening the hole you made, and making it useless for that fastener. You will either have to head back to the store for a thicker, heavier duty tapcon screw, and larger drill bit for same, or find a way to abandon that hole and try another. Which leads to:

4. Penalty if you screw up - once you start making a hole if position is not right, it will be impossible to shift it or angle it like with soft wood. Layout your holes carefully. Make your goal to dimple the surface first before you drill holes to depth. Plan so you can abandon a few things. Or,

5. use Tapcons to fasten a length of wood to the wall, then attach to the wood with wood screws. Much more flexible and forgiving for placement. You mentioned Heavy Things so...

6. Only trust tapcons to hold load in shear - perpendicular to the axis of the screw. Tapcons may be rated for 600# but if you are putting one straight up into a ceiling, I would not hang more than 5# from that.

7. Beware brittle concrete. Beware driving the tapcon in too much - if the head of the fastener pulls tight to the edge of the hole and you keep spinning/driving, it will auger out the hole or snap.

8. Finally, after making the hole, you have to drive the tapcon fastner (screw) with something. I find the hammer drill, with a heavy duty hex-driver bit, and the hex-head tapcons to be the best. Go easy so you do not overdrive. It is very easy to strip out screws or bits for the phillips head tapcons.

Good luck!
posted by sol at 8:04 PM on July 11, 2017 [3 favorites]

Yeah, it's pretty easy. Buy or rent a cheap hammer drill and get some tapcons.

Wear goggles and a dust mask.
posted by bondcliff at 6:46 AM on July 12, 2017

Yes, I want to anchor shelves (I have a clumsy cat and I don't want to come home to him in pancake form) and I'm also thinking about hanging pegboard in my kitchen. Thanks for all the detailed advice so far! One more question, just to bring this back to the original question I had--is this something a makerspace/hackerspace could help me with and are there any in DC where I can drop in without a subscription?
posted by capricorn at 7:38 AM on July 12, 2017

OK, I guess "are there any in DC where I can drop in" is a googleable question and this one in Silver Spring has day passes. But would that help? Or are makerspaces more for people who want to use 3D printers and more advanced prototyping tech?
posted by capricorn at 7:45 AM on July 12, 2017

Nah, just go for it. You don't need help.
posted by humboldt32 at 8:58 AM on July 12, 2017 [1 favorite]

Agreed, just go for it. And heed Mitheral's and sol's advice on the Tapcon screws - I wish I knew earlier about the problem with overtightening them!

If you strike out renting a hammer drill you can maybe borrow mine.
posted by exogenous at 10:38 AM on July 12, 2017 [1 favorite]

OK! I am nervous but you have all given me much more confidence than I had when I made this post.

If you strike out renting a hammer drill you can maybe borrow mine.

DC MeFites are the best. <3
posted by capricorn at 11:57 AM on July 12, 2017

Def. rent the hammer drill if you can get it.

If you're still nervous and have a car you could always go out to e.g. Community Forklift and see if they have something you can drill. If you run out of options I have some concrete in the yard up in Takoma . . .

If I were really looking for practice I would probably just drill a hole somewhere else in the wall that's somewhat unobtrusive; then you can practice patching too!
posted by aspersioncast at 1:24 PM on July 12, 2017 [2 favorites]

sol nails it. Tapcon, hammer drill rental, layout carefully, hold drill as level and straight as you can (an observer off to the side is great for this if you aren't confident but they need not be pros by any means), and full power on that trigger. You'll get it.
posted by RolandOfEld at 7:39 PM on July 14, 2017

Bonus points if you layout beforehand to save rental time/length/cost. Should be doable in 4 hours or less, depending on traffic back to the home Depot.
posted by RolandOfEld at 7:43 PM on July 14, 2017

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