Drilling tapcons into hollow blocks

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Is there any special tricks in using Tapcons on hollow concrete block walls?
I want to secure copper pipes, PVC drain pipes etc... onto my block walls using those copper straps. I am using 1-1/2" Tapcon screws and drilled a hole then when I feed in the screws it reached bottom and spins. The straps are still secured in that I can't pull them out, but I would prefer I can drive the screws in and be tight and snug.
The block walls are built with the typical 8" thick hollow blocks with a web in the middle. I think if I drill into the solid part of the block it's better but most times this is not practical as the pipe may be a vertical run from floor to ceiling and I want to secure it in say three spots and they are all in the thin part of the blocks.
Is there a trick? Will a specific size and length work best, reading the Tapcon website it says it needs a minimum embedding depth of 1" to a maximum of 1-3/4". It looks like the blocks are about 1" thick. When I drill them sometimes it punches through and sometimes it does not. I am just not doing something right so I stopped before I drilled too many holes.
Thanks in advance for any suggestions.
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On Wed, 3 Feb 2010 12:58:59 -0800 (PST), MiamiCuse

Try shorter screws?
Are the screw threads the full length of the screw shank?
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On Wed, 03 Feb 2010 13:19:13 -0800, Oren wrote:

It is better to drill into the mortar between the blocks.
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wrote:

Not really, drilling into the mortar is easier but the mortar is not hard enough to support much weight not hold many anchors. Most Tapcons will not hold in the mortar but will just enlarge the hole and fall out. The Tapcons I have purchased in the past only called for 1" to 1 1/4" penetration into the concrete not up to 1 3/4".
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On Wed, 3 Feb 2010 18:20:26 -0500, EXT wrote:

Drilling into the hollow area often breaks the inside of the hole, reducing the bite of a Tapcon. Mortar will hold tapcons very well for the OP's intended use. If you have trouble with enlarging the hole you can use an expanding rivet type anchor or use foil to get a grip.
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On Wed, 3 Feb 2010 18:25:26 -0600, Michael Dobony

Drilling a pilot hole into a block cavity will not cause it too "break" inside the hole every time.
The OP was smart to ask his question. It amounts to a simple tap into the wall, cavity or not.
Rivets are not worthy, for this task?!
...short screws...
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On Wed, 03 Feb 2010 23:32:06 -0800, Oren wrote:

No, maybe not every time, but much of the time. It is more reliable to drill into the mortar than the block.

For holding a pipe strap? Have you looked at rivet type expanding tip anchors? They have a pretty good holding power. You put it in all the way into the hole and drive the pin in with a hammer. The end expands considerably and creates quite a grip.

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Michael Dobony wrote:

Whatever happened to using a ramset or construction adhesive to apply a 1x4 to the wall, and screwing the pipe clips to that? Not like they take a lot of weight- I presume OP is just trying to make the place look tidy, and reduce rattling from air bubbles and pressure changes. I think OP is making this project a lot harder than it needs to be.
-- aem sends...
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wrote:

That's how I've seen the pro's do it...Things tend to get a little over thought sometimes in the my idea is better contest...LOL...
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I don't think hitting the hollow part of the block is the problem. As the box says, the 1" thickness of the block ought to be enough to get the screw snug. If the screw is turning freely, then you've stripped the threads that the screw has cut in the concrete, it's really got nothing to do with whether the tip has entered the hollow void.
I'd say your drilled holes are too large. Are you using the specified bit for that size of tapcon? (Some packages include a bit; all of them tell you what size to use.) I've used tapcons occasionally and I often find that the bit wanders or precesses enough that it creates a bigger hole than it ought to. So maybe try a slightly smaller bit.
Chip C Toronto
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I know I am using the correct size bit because the bit came with the screws.
I also don't think I am "stripping" the threads at all, because I can back a screw out and then use it in another spot and it would work.
It's a hit and miss, and misses more than hits.
Thanks,
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re: "I also don't think I am "stripping" the threads at all, because I can back a screw out and then use it in another spot and it would work."
The issue is not with stripping the threads on the screws, but with stripping the hole.
Once that happens, there is no way to make the same size Tap-Con work in that hole again. Once you've spun one, forget that hole and move on.
If you absolutely need to place a screw in that location, fill it with epoxy or something and start over.
You have to extra careful when using Tap-Cons in block walls. You have to get a feel for the speed of your driver so that you drive them fast enough so that they bite and become snug, but not so fast that you strip the hole.
Here's an FAQ on tap-Cons:
http://www.concretescrews.com/tapcon-questions.aspx
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You can add a piece of #12 electrical wire (leave the insulation on) and reinstall the Tapcon, it will hold quite well. This method works just as well using drywall and other screws in CMU walls. It does a tremendous job holding concrete forms to a slab with double head 16's also.
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You're stripping the HOLE, not the screw.
If you are using a cordless drill to drive the screws, you need to loosen the clutch up so it clicks before you strip out the screw.
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The problem isn't with the screws, it is with the holes you are drilling... You need to be more careful and hold the drill at a 90 degree angle to the surface you are drilling into without letting it wiggle around... Some double stick tape and a speed square can help guide you if you need a point to reference to...
It sounds like the drill is making too large of a hole because you are putting too much force on it and the drill bit is flexing under the pressure and drilling a larger hole...
Let the drill do the work, gently guide it forward...
If you still have problems with using these screws, you can find and use a slightly smaller hammer-drill bit until you find one that works and gives your screws good bite with your overly forceful style of drilling...
~~ Evan
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It sounds like the hole is a little bit too big for the tapcon. I would put some epoxy on the female portion, place it in the hole, and then wait for the epoxy to set and then insert and tighten the screw.
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On Wed, 3 Feb 2010 18:06:19 -0800 (PST), "hr(bob) snipped-for-privacy@att.net"

What if one whittles a wooden peg, inserts it and snug's the screw?
Cheaper than epoxy?
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wrote:

Do you even know what you're talking about?
What female portion? Tapcons drive directly into the concrete.
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On Feb 4, 12:09pm, snipped-for-privacy@rochester.rr.com wrote:

I meant as opposed to the screw that he thought was stripped.
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I agree with Chip C. My experience is that the dedicated drill bit wanders thereby causing the pilot hole to enlarge. Probably should try a smaller masonary drill bit which will cut you some slack in the diameter. Also no one has mentioned using a rubber bulb to remove the masonary dust from the pilot hole.
Joe G
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