Filling deck holes with epoxy

JonnyBoats · Post by **JonnyBoats** » Sat Mar 15, 2008 3:55 pm

How can one keep West System epoxy fro running out the bottom when filling a deck hole? I am thinking of the bolt holes left when one removes a deck fitting, 1/4 to 1/2 inch diameter.

I tried using duct tape over the bottom of the hole, but unthickened epoxy simply runs past the stickey tape.

Rachel · Post by **Rachel** » Sat Mar 15, 2008 4:03 pm

I used (3M brand) clear packing tape. Not the fiber-reinforced stuff, but just plain clear. The kind that comes on a little plastic throw-away dispenser and is ~2-3" wide. In filling dozens of holes, I had no problem with run-out, nor with removing the tape afterward. A bonus of the clear tape (and why I switched from blue masking tape) is that you can see whether or not you have the hole properly filled at the bottom.

Sometimes I filled from the top, but other times (depended on various factors), I would simply jab my syringe into the tape from the bottom and fill from there, like you do the lower unit in an outboard. Fill, pull it out, slap another piece of tape over the hole.

In either case, I had blue tape on the deck around that side of the holes, to guard against overflow. When the cured epoxy was in the "green" stage, I'd go back and chisel the "mound" off the deck.

Rachel

Hirilondë · Post by **Hirilondë** » Sat Mar 15, 2008 4:05 pm

Why not thicken the epoxy? Actually, I highly recommend it. Maybe use a little colloidal silica for adhesion and some micro-balloons to make it sandable. Tape on the bottom is a good idea, and will work for thickened epoxy.

Post by **Tim** » Sat Mar 15, 2008 4:58 pm

I can't imagine trying to fill holes without thickening the epoxy--what a mess, never mind the fact that plain resin with no thickeners is brittle and weak in comparison. If you want, dab a bit of the unthickened epoxy around the hole's edges (i.e. the exposed core) before you mix in the filler; then mix the filler and install the epoxy in the hole.

When installing hardware in overbored holes, I normally use just silica as the thickener, since sandability isn't usually an issue. Tape of almost any kind over the bottom easily holds the thickened epoxy, but I usually use masking tape because it's always on hand and works well. I never use duct tape for this sort of thing (or for anything, actually).

Rachel · Post by **Rachel** » Sat Mar 15, 2008 5:15 pm

Oopsie! I just assumed you were using thickened epoxy. I thickened mine with colloidial silica. As Tim mentions, I "painted on" some neat epoxy first, because I thought it might better seal the surrounding core. Of course, even my thickened mixture (mayonnaise consistency) needed the bottom of the hole taped.

Rachel

Ancient Race · Post by **Ancient Race** » Sat Mar 15, 2008 6:23 pm

I've always taped the bottom of the holes - slitting or puncturing the tape slightly to allow the air to escape, to ensure a solid plug - then filled flush from above with epoxy thickened with colloidal silica.

If the area below requires a finished surface, it's easy enough to just knock off the resulting burr.

Greg

Ceasar Choppy · Post by **Ceasar Choppy** » Mon Mar 17, 2008 10:02 am

I've used duct tape for this before with varying degrees of success. Two things I've learned:

1) there is a lot of cheap duct tape out there. 3M is the best IMO.

2) You really nead to press the tape HARD over the hole and make sure it is sticking by moving your finger around the edges of the hole. Sometimes it sticks, sometimes it doesn't. It helps if you clean the area with some acetone beforehand.

Come to think of it, these points apply to pretty much all kinds of tape in this situation.

Quetzalsailor · Post by **Quetzalsailor** » Mon Mar 17, 2008 4:38 pm

John,

Have you got the overhead out of your boat, too? How does it come out? I presume handrails and corner trim out, how much more? Were you able to get it out without breaking it? Awful job? How about over the head? (It's on my 'dread' list, but necessary for mounting the fittings for leading lines aft.)

As for the question at hand, I've always succeeded with duct tape. Clean smooth surface, well pushed on. I've done larger holes by duct taping the surface of a piece of plywood of suitable flexibility and propping it ferociously against the surface (pretty hard to get a decent seal even if you're periously close to distorting the boat).

I wonder if you missed telling us that you were trying to seal against the underside of the deck which, I'll bet, is pretty rough - a roving surface. Tougher to seal against. The thickened epoxy will suffice.

All previous points about filler are right on and there's not so much drool-ey material with filled/thickened mix. I've even added chopped glass fiber to the thickened mix on occasion.

A point left unmade is that the bore has to be clean, too. Drill the hole out a tetch so as to expose bright, clean fiberglass, no oil, no sealant. A fuzzy hole is just fine: lots of shaggy fiber to bond to.

Doug

David · Post by **David** » Sat Mar 22, 2008 6:16 pm

JonnyBoats wrote:How can one keep West System epoxy fro running out the bottom when filling a deck hole? I am thinking of the bolt holes left when one removes a deck fitting, 1/4 to 1/2 inch diameter.

I tried using duct tape over the bottom of the hole, but unthickened epoxy simply runs past the stickey tape.

John,

I use 3M blue tape and never have a leak. I overbore all holes thru my cabintop and deck, wet out with unthickened epoxy, fill with thickened epoxy and then redrill the correct sized hole. A little blue tape over the underside hole prevents all leaks.

David

hebert01 · Post by **hebert01** » Sat Mar 22, 2008 6:40 pm

If I'm adding new holes in a cored deck, typically I'll drill through only the top and the balsa core with my oversize bit, but leave the bottom skin intact. Then I excavate and clean the hole area, fill w/ epoxy thickened w/ silica or mirocrofibers, and then go all the way through the deck with the proper sized bit once everything's cured. Makes for a very clean install, and the underside sees no evidence of the epoxy filler.

With old holes, though, I've had luck with good ol' blue 3M tape. Just apply it your underside surface cleanly, pressing firmly around the outside circumference of your hole. Should be all set. Again, thicken the epoxy so it's got some viscosity and doesn't flow like water.

Jasper Windvane · Post by **Jasper Windvane** » Tue Mar 25, 2008 10:25 am

I use electrians putty,, the stuff they put into holes to stuff up when
running wires.. it is like a putty material.. got it at Lowes.. just take a small amount, stick it on the bottom hole,, it holds back the epoxy until dry.. then? pull the putty off..

Zach · Post by **Zach** » Tue Mar 25, 2008 2:43 pm

Question:

When you guys are filling these holes, does it take a second trip around after they cure? I poked around with a drill bit, and a lot of the ones I filled skinned on top, but had a nice air pocket inside.

I'm mixed up to about ketchup consistency pondering where the air was going to go once I blobbed in the thick stuff. Hmm.

Ancient Race · Post by **Ancient Race** » Tue Mar 25, 2008 2:48 pm

Zach wrote:Question:

When you guys are filling these holes, does it take a second trip around after they cure? I poked around with a drill bit, and a lot of the ones I filled skinned on top, but had a nice air pocket inside.

I'm mixed up to about ketchup consistency pondering where the air was going to go once I blobbed in the thick stuff. Hmm.

Zach - if you use tape, a small hole or slit in the center will allow the air to escape.

Greg

Zach · Post by **Zach** » Tue Mar 25, 2008 2:51 pm

Excellent!

Thanks for the tip.

Zach

Ceasar Choppy · Post by **Ceasar Choppy** » Wed Mar 26, 2008 8:05 am

There are always lots of air bubbles, but as long as it can settle out before it cures, the worst that can happen in that you have to re-fill the holes a little, but the epoxy has creeped into most of the hole.

I've found that using a syringe is very helpful in filling those holes. That and making the epoxy kind of runny.

Quetzalsailor · Post by **Quetzalsailor** » Wed Mar 26, 2008 9:15 am

Depends upon the depth of the hole. This string started with a fellows' question about his Airex-cored deck. It's about an inch thick with 1/8"+ faces and the bottom face is rough fiberglass. So, there's an art to be learned to include: how much neat epoxy you need to wet out the inside surfaces, how long you have to wait for the surrounding material to take up, whether you ought to reapply some neat, and both how you get the neat to coat the entire bore as well as how you get the thick stuff to the bottom of the hole, and lastly how to not make a disgusting mess either below or on top.

Solutions include adequate tape and tape application for the bottom, squshing the neat around with a dowel, splinter, nail or other probe, tamping the thickened with the probe, cleaning up the mess, refilling, preferably while the mix is still soft.

I've filled screw holes in the wooden FD keel with dowels installed wetted out, into wetted out holes and filled with thickened mix. The ingoing dowel is the probe and if put in with adequate, but not excessive, force, it serves to push the epoxy into the surrounding wood and joints. And the dowel becomes the replacement for the screw. The winter's house project finished up with my repairing the nail holes in face nailed 5/16" strip oak flooring. I wetted out and filled the holes from the underside using epoxy filled with sanding dust. Even as thin as that, I had to go round and refill the holes before they were hard, because the wood absorbed so much of the neat epoxy. I reinstalled the strips in the same places by drilling through the old nail holes and the new epoxy.

Filling holes permanently in a thick, cored 'glass structure could use the same trick if the dowel segment was of the appropriate length; it would be encapsulated. Filling the core and reinforcing for new fastenings is less of a problem since you want an annulus of filled epoxy to carry load and keep the core from crushing; the fill hole can be larger. Some folks like to drill the hole and scoop the core out with a bit of bent wire chucked up in the drill; very neat idea but the art of doing it well, reliably, and quickly seems more daunting than drilling oversize.

I've used the expensive hypodermic-ish injectors that West sells, but with limited success. So: wet out, squchie the neat stuff in and around to wet out, ditto the filled stuff, consider the dowel, refill before hardening, clean up. You can also clean up the nearly hard stuff using a razor blade or similar; saves grinding.

CharlieJ · Post by **CharlieJ** » Wed Mar 26, 2008 9:46 am

Getting difficult to find 'em, but I use a doubled pipe cleaner to wet out the inside of holes, etc.

Zach · Post by **Zach** » Wed Mar 26, 2008 9:50 pm

Pipe Cleaners... cool.

Have you guys and gals figured out a way to recycle the syringes? I haven't played with loading my own. (I was reading the other day about recycling used caulk gun tubes doing fillets...)

CharlieJ · Post by **CharlieJ** » Thu Mar 27, 2008 12:21 am

I just go to the drug store and buy new ones- 50 cents a piece. A vet friend gave me some cattle needles - those have BIG tubes- sure pity the cow. But they work great for epoxy- just wash 'em out with vinegar

Ceasar Choppy · Post by **Ceasar Choppy** » Thu Mar 27, 2008 9:00 am

Zach wrote:Pipe Cleaners... cool.

Have you guys and gals figured out a way to recycle the syringes? I haven't played with loading my own. (I was reading the other day about recycling used caulk gun tubes doing fillets...)

I use acid brushes to wet-out the holes. You can get much smaller ones if you need them from sources on the internet or hobby stores. They are much cheaper than the West System brushes.

The syringes are meant to be recycled... otherwise they wouldn't make them out of plastic! lol

I recycle the syringes by leaving just a little bit of epoxy in the tube with the plunger in contact with it. Once the epoxy has cured, you need to try and bend the syringe a little (don't really bend it, but try and get the epoxy to separate from the plastic a little), and then pull out the plunger. The excess epoxy usually comes out in one piece. If it doesn't, take a small pick and poke it through the nose of the syringe to get the epoxy out. I usually get 3 or four uses out of one syringe, before the plunger gets buggered.

Rachel · Post by **Rachel** » Thu Mar 27, 2008 9:47 am

Ooh, nice tip on recycling the syringes.

I have a couple of large ones I got from my vet, also, and they're my favorites (although I also keep the smaller ones on hand).

Zach · Post by **Zach** » Thu Mar 27, 2008 7:23 pm

Vinegar. Another thing to try... thanks guys!

I'll track down some syringes and add them to the arsenal.

This place rocks...

Zach

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Filling deck holes with epoxy

Filling deck holes with epoxy

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