Epoxy Detail Question

[GregE]

To completely seal wood that will be screwed into something, I know it's advisable to drill the holes oversized, fill with epoxy, let it harden, then screw into the epoxy.

When filling the holes, that wood obviously needs to be laying on something so that the epoxy will not run out the bottom of the hole, but of course that backing is going to be bonded to those holes once the epoxy dries. Having never used epoxy, I don't have any experience with it and maybe it's a non issue. Do I just lay the wood flat on another piece of wood and it will break loose without a problem once dried? Is this the best way to back the screw-holed wood for this process?

 

[qaztwo]

Re: Epoxy Detail Question

Will it break lose yes, will it be neat or easy no. wax paper works well as does duct tape.

good luck.

 

[qaztwo]

Re: Epoxy Detail Question

By the way add filler to the epoxy. I like milled fiberglass.

 

[jcsercsa]

Re: Epoxy Detail Question

Cool I was thinking on doing my drain hole like this , it should work shouldnt it ?? thanks John

 

[erikgreen]

Re: Epoxy Detail Question

The easiest stuff I've found to work with for this is wood flour in epoxy... basically fine ground sawdust. It isn't quite as smooth as using cabosil (silica) but it's structurally stronger.

Mix enough with the epoxy to end with a mixture about the thickness of peanut butter (that's what it's usually called). If you get it thick enough it will not droop much or run.

Alternatively, you can use a pre-mixed product called marine-tex, which is fairly thick anyway, and has some other nice properties.

Note that you don't need to drill the hole you're filling all the way through if it's for a screw... just drill deep enough to seat the screw. If you must drill through, you can use almost any smooth plastic, like a ziploc baggie or saran wrap or a piece of plastic bucket or whatever to plug the other side up... just make sure you tape it down tight or clamp if possible to avoid runs or leaks.

Erik

 

[Old Salt Oz]

Re: Epoxy Detail Question

If you are filling holes that will have screws or bolts through them avoid using any porous fillers like wood shavings or talcum powder, they will take up moisture or not provide you with a high strength needed if screwing rather than bolting. Micro Balloons fall into the too soft category for fixing holes also.

Screw and bolt holes should be drilled oversize and both ends of the hole should be a larger diameter than the mid point, so you finish with hole shaped like a capstan when viewed side on.

Filler should be fine ground fibreglass or Micro-fibres, not balloons.

Masking or other tapes will prevent the mixture running out the far end, but best applied 'after' the resin and filler has passed through and removed any air gaps. This stuff is very hard to sand off when cured, so take some time to clean up and save some time and effort later.

No resin or filling should be applied unless the area is confirmed as being very dry, failure to check may result in timber rot because you will be sealing moisture Inside.

Best done with a temperature above 20*c for the full 24 hours after application and Humidity below 73% for 12 hours.

I hope this helps.

Avagoodweekend......

 

[qaztwo]

Re: Epoxy Detail Question

I don't know if I understand. In the picture shows where the stringers and bulk heads are. are you wanting to drill holes in your stringers and bulk heads. If so there called limber holes and just coat those with a layer of expoxy to seal them.

 

[GregE]

Re: Epoxy Detail Question

The easiest stuff I've found to work with for this is wood flour in epoxy...
Alternatively, you can use a pre-mixed product called marine-tex, which is fairly thick anyway, and has some other nice properties.

Is epoxy (with no filler) thin enough that it could be picked up in a drinking straw by putting the straw into a container then putting a finger over the top of the straw? That would be a very clean and easy way to drop just the right amount into the drilled holes. Is that feasible?

 

[Coors]

Re: Epoxy Detail Question

MAS with slow hardener will probably do it. no epoxy sticks to saran wrap.

 

[Old Salt Oz]

Re: Epoxy Detail Question

<<<Is epoxy (with no filler) thin enough that it could be picked up in a drinking straw by putting the straw into a container then putting a finger over the top of the straw? That would be a very clean and easy way to drop just the right amount into the drilled holes. Is that feasible?>>>

Yes, however epoxy with no filler (Fibres) is not nearly as strong and will be brittle.

You van mix the required amount of fibre and dispense it via a large syringe, available at most chemists or Drug stores.

I hope this helps.

Avagoodweekend......

 

[Old Salt Oz]

Re: Epoxy Detail Question

If you are looking for a simple way to seal limper holes, use short lengths of conduit; smear the hole and the conduit then slide into position and wipe away any excess mixture.

The resin must contain enough fibre to prevent it running out.

Avagoodweekend......

 

[jasono2l]

Re: Epoxy Detail Question

How do you thin out epoxy to " paint" it on your deck wood to help make it waterproof?

 

[Old Salt Oz]

Re: Epoxy Detail Question

To improve penetration you can mix a batch or epoxy resin then add Methylated Spirits to 30% by volume; this will leave only a very thin coating on the surface and more resin should be applied over this.

You can avoid sanding between coats by applying wet on tacky using small batches.

Avagoodweekend......

 

[seven up]

Re: Epoxy Detail Question

For thinned epoxy I use laquer thinner and 1:1 ratio epoxy. Up to 100% by volume. For example 6oz 1:1 resin, add 6oz 1:1 hardener, mix and blend, add 12oz laquer thinner. Works well for penetrating and I always wash the surfaces first with laquer thinner or acetone. This has worked for me as an economical alternative to the manufactured versions of thinned epoxy.

This is not for laminating or glueing, just a sealer.

 

[Coors]

Re: Epoxy Detail Question

Different epoxies use different thinners...

 

[GregE]

Re: Epoxy Detail Question

.....epoxy with no filler (Fibres) is not nearly as strong and will be brittle.

I didn't realize that, thanks.