Drill oversize holes- fill with epoxy - how ?

abl1111 · #1 04-21-2005, 04:17 PM

I want to oversize-drill several bolt holes through my transom ( under the water line ) to mount a swim platform. And, although I understand the theory of this, I want to brush up on how to properly, and completely fill these oversized holes w/ epoxy - so when cured I can drill through them w/ a smaller drill and mount my swim platform..

And, has anyone done what West System refers to in their manual w/ regard to epoxying a hole, and while wet, installing a bolt or screw in to assure maximum grip / water proof'ness ?

Thx

Ed · #2 04-21-2005, 07:46 PM

ABL-

Basically, you drill the hole a size or two larger than what you need and then you fill it in with a epoxy/cabosil mix. You want the epoxy to be thick like peanut butter so that it stays in place......be sure to force it in the hole with a spreader. Than take a piece of wax paper slightly larger than the hole and tape over it with duct tape. That will make sure that an epoxy does not spill out. Let cure for a day or two than redrill the hole to the appropriate size.

abl1111 · #3 04-21-2005, 08:54 PM

Ed,

Thx. I just want to fill the drilled out hole 100% w/ epoxy. Being that I won't have gravity work w/ me - more against me, I want to make sure that the epoxy does not 'trick me' into thinking it has filled the void , when in fact it has left aripockets throughout.

I guess I could also push the thickened epoxy into the hole until it comes out like toothpaste from the other side - maybe even have someone there on the receiving end to catch the exiting epoxy and re-use on next hole?.

Finster · #4 04-21-2005, 09:19 PM

You can also use a dowel. Drill your hole until you find dry wood, coat the hole and soak the dowel with epoxy, and drive it in. Don't make it flush. Leave enough room for little cabosil and gelcoat finish.
The other thing you can do is drill an 1/8 inch hole above and on a 45 degree angle into the main hole, fill cabosil into the main hole til it comes out the small. Cover the main hole with something no stick, and top off the small hole. That way you won't have to worry about the air pockets you'll get if you just tried to jam cabosil in a horizontil hole.

Good luck.

RS · #5 04-22-2005, 07:02 AM

I'd whet out the inside first with unthickened epoxy using anyting handy (q-tip, small brush, etc.)
Then use a meat infusor to inject the cabosil mix from the back of the hole forward, withdrawing the needle as you finish injecting. The infusor looks like a big hypodermic syringe with a plastic needle. They are about $4 at X-marts.

Tape over the hole until it first sets. You can use a putty knife to scrape it level while it's a little soft.

warthog5 · #6 04-22-2005, 12:23 PM

I'll give you a little diffrent play on what Roger said.
You can buy large suringes from the drug store. They run $1 to $2 for a 60cc suringe. If you wipe them out with a paper towel and shoot actone thru them twice you can reuse them time and time again.
Use an old tooth brush to wet the core out in the hole first with stright mixed epoxy.
You can cover the hole when filled with just Duct tape. No need for waxed paper. the area around the hole must be dry for it to stick. Duct tape will not stick on wet epoxy surface.
Before you start to fill the holes. tape right around the holes and put a piece of Visqueen all around it. That way any spillage is a easy clean up with just removing the tape and visqueen.
I recently installed a kicker motor bracket. I used some stainless steel tubing and stood it on end. Filled the tubing full of epoxy/cabisol. then I beded the tubing in the holes with more epoxy/cabisol. The new mounting holes were drilled thru the middle of the stainless tubing. 4 holes with 5/16 carrage bolts to hold the unit on. I garantee you could pick the ass end of the boat up off of that mount. It had alum backing plates on it too.

saltydawgrods · #7 04-22-2005, 02:05 PM

So what if you are doing this in the deck and you can't het to the back of the drilled hole to put a stop? How do you keep the epoxy from dripping through

warthog5 · #8 04-22-2005, 03:34 PM

You use a Forstner bit and don't drill thru the bottom side glass skin. I use them a lot. They make a nice flat bottomed hole. These have held up pretty good.
http://www.harborfreight.com/cpi/cta...emnumber=47128

abl1111 · #9 05-03-2005, 08:54 AM

Thx guys. I installed the brackets and swim platform via drilling oversize holes and using epoxy. A few things I found that might be yseful for the next guy doing this:

First, I bought a drill guide @ Home Depot, by "General" for about $35 - this allowed me to drill the oversize holes exactly perpendicular to the transom - then, after I epoxied these holes, I was able to use this guide again to re-drill the smaller bolt holes at an exact perpendicular again, assuring that this bolt hole stays within the epoxy I've set.

Next, when injecting the epoxy, I used a large syringe ( no needle ) that I could not find anywhere! except, finally at a medical supply store for a cheap $1.25 a pc... Perfect to inject the thickened epoxy.
If you have two people to work on the epoxy, I would recommend a different approach - having one person in the boat, the other on the outside. Make epoxy to mayonnaise consistency. Tape off all areas around each hole first. Then, with a plastic spreader, 'jam' epoxy into the hole from the outside - in. As it come through the hole, the guy in the inside will 'catch' the epoxy with his spreader, wiping it on a pc of cardboard ( or something ), until the flow of epoxy coming out is an even flow - then you know that the epoxy has filled the drilled hole, with no air voids.

Repeat with each hole... The epoxy cured and I drilled through it and then installed brackets, via bolts, Boat Life, washers, locknuts... and finally the platform.. The thing is rock solid !