Drilling into concrete underwater

[Tim Frank]

I have a boathouse repair to make.
Part of the plan requires drilling ~20 holes 3/4" diameter x 2" - 3" deep to set Rawl anchors, in a depth of 2'-10' of water.

Has anyone ever drilled into concrete underwater?

The drill bit should be OK as just a standard carbide-tipped masonry bit....but what about the drill?
My keen and insightful mind ( ) has already twigged to the fact that my 110 volt hammer drill might not be a great idea...and for similar reasons, my battery powered drill is a no-go , too.

But will a pneumatic drill operate OK at a depth of 8-10 feet? In the back of my mind I am wondering if the greater external pressure (say an extra 5-8 PSI ~ 30-35%) may overload the drill.

I have SCUBA gear and am certified so i don't have to drill a minute or 2 at a time....

 

[rbh]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

sounds like an interesting job you have going on!
I might give the old air impact a whirl, just because.

 

[Tim Frank]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

When I said "pneumatic drill" I meant air-operated drill ....the $50-$100 Harbour Freight or Cambell-Hausfield item....not the road crew, large compressor, hard on a hangover, one....

 

[marlboro180]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

Tim,

Dunno if a pneumatic drill would work underwater , but those air drills usually run some pretty high rpms. You would also need some way to tie yourself to the work area so you do not push yourself right back up to the surface while pressing down on the drill, unless you are wearing some heavy, heavy weigh belts.

Got any money in the job for some rugged bit extenders? I got a few of them for spline shaft (fits a Milwaukee Thunderbolt Electric hammer drill) . They are about 2 feet long, screw together and work really well. Think I got them at Grainger. $$$$ I had to go 6 Feet through some bricks and stone. Amazingly went really straight.

Another thought- how about a hydraulic drill??? http://www.stanleyhydraulics.ca/handheld/drills.shtml

I have used hydraulic chainsaws underwater, and as a side note the WI DNR recommended the use of veggie oil in marine environment of the project I was on. Worked great.

BTW- an electric chainsaw will run pretty long underwater- about 60 seconds

 

[Tim Frank]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

^ ^ ^
Great input , thanks!

Tim,

BTW- an electric chainsaw will run pretty long underwater- about 60 seconds

And BTW, your chainsaw secret is safe with me...

 

[rbh]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

When I said "pneumatic drill" I meant air-operated drill ....the $50-$100 Harbour Freight or Cambell-Hausfield item....not the road crew, large compressor, hard on a hangover, one....

yes, just the little guys

 

[bruceb58]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

Water will enter the air drill chambers long before you get to turn it on. There are underwater drills made for this type of thing but very expensive.

 

[Tim Frank]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

Water will enter the air drill chambers long before you get to turn it on. There are underwater drills made for this type of thing but very expensive.

If you were "gentle" starting up could the air chambers clear?
I priced a hydraulic drill and they start at ~ 1200-
Ouch...

 

[Tig]

Re: Drilling into concete underwater

Re: Drilling into concete underwater

Would a Ramset do the job?
Certainly cheaper to try although hearing protection may be an issue. Sound waves are intense underwater. I've never used one so I'm not certain how loud they are.
If water causes a misfire you could put the tool in a plastic bag to keep it dry until it is fired. Once you set the pin, return to the surface, blow the tool out with compressed air, reload, re-bag do the next one. A bit of a process but it sounds like a workable option for under $100. Also a lot faster than drilling.

 

[funk6294]

Re: Drilling into concrete underwater

I dont think you would have a problem with water entering the drill if you leave it running the whole time. Simply tape or wire the trigger so it is on all the time. If you want to vary the speed or slow it between holes then put a ball valve inline and use that to throttle back the air, but always leave air going through the drill, this way water will not enter. And like you were thinking i would use a Harbor Freight special on that one so that even if it dies its no big deal.

EDIT: Looking around on Google it looks like people commonly do this and it is acceptable to use the HF drill...

http://coral.aoml.noaa.gov/pipermail/coral-list/2007-February/004090.html

 

[Tim Frank]

Re: Drilling into concrete underwater

I dont think you would have a problem with water entering the drill if you leave it running the whole time. Simply tape or wire the trigger so it is on all the time. If you want to vary the speed or slow it between holes then put a ball valve inline and use that to throttle back the air, but always leave air going through the drill, this way water will not enter. And like you were thinking i would use a Harbor Freight special on that one so that even if it dies its no big deal.

EDIT: Looking around on Google it looks like people commonly do this and it is acceptable to use the HF drill...

http://coral.aoml.noaa.gov/pipermail/coral-list/2007-February/004090.html

More great info, thanks.
Sounds like these guys are in much deeper water 30 ft + which is a different world from where I am....less than 10 feet and fresh water....worth a go.
Be a month or more before I get to it, but I'll report back how it works.

 

[j_martin]

Re: Drilling into concrete underwater

I wouldn't be afraid to run an air operated drill underwater. When you pull the trigger, it'll blow the water out. I'd rig a fairly fat oiler with an environmentally friendly oil, (probably some sort of a synthetic,) and give it a good dose of air tool oil after you surface.