Whata sort of epoxy

[Chris]

I am fitting a new drain bung into the transom. Where I have had to open up the hole through the transom that was there originally I want to seal the bare wood around the hole.

What sort of epoxy would be suitable for this, can I just use any 2 part resin glue like araldite or the stuff my local hardware store sells that is a slightly runnier version of araldite or does it need to be special stuff.

Thanks !

[mister p]

Chris, there may be a case here for blanking off one side of the hole. Then force epoxy (fibreglass resin will do the same job) with a syringe into any gaps between fibreglass and ply, if there are any, plug the hole with whatever the transom is made of (ply or glassfibre) and blank the opposite side ensuring the volume between blanks is full. Leave to set, remove the blanks from either side of transom. Flat both sides down and rehole.
In short........rebuild the existing hole and redrill a new one.
That way all the old guff is cleaned out and restrengthened and proofed. Now you can redrill precisely for your new bung. Maybe even reposition.
The other idea is that if it is a wooden transom, then it's simply a case of making a larger neater hole to cut out any opened up timber (that water ingress would have caused), sealing with epoxy, marine lacquer or silicone ( or all) and fitting a new unit. Here you cut to fit your new bung, not find a new bung to fit your new hole!

[Chris]

Hi there, the old bung was sealed in with silicone so its not suffered water ingress and the wood is firm and dry, its just the new bung is bigger and I would rather not rely on silicone.

[mister p]

Chris, I understand you don't want to use silicone, but you have said that previously it was sealed with silicone and is firm and dry.
So, I would prepare the new hole to take your new fitting by feathering any sharp edges with fine sandpaper and then feed three coats of 50/50 varnish/thinner onto the virgin wood to allow it to wick in. Then a few coats of varnish proper, as per manufacturers recommendations. Let it dry. Then a fine lick of silicone before the final fit. Put a dab of silicone into the pre-drilled screw holes before fitting the screws and you'll be set to go.
It works.
Epoxy may crack with the expansion of transom with temp variations and silicone will carry that.
It will be good for years, honestly.

[Chris]

Useful info and it makes sense, thanks

[mister p]

Chris, it's just the difference between working with timber and glass. It works, timber needs movement and glass needs a chem fix.

[mister p]

Just read the title, maybe youa aftera Italiana epoxya si?

[bedajim]

Chris

Silicone is for bathrooms and not to good at that
Use sikaflex
Jim

[Chris]

Originally Posted by bedajim

Chris

Silicone is for bathrooms and not to good at that
Use sikaflex
Jim

Totally agree, I would always use Sika for something like this... but wanted to go belt and braces before refixing the bung in.

How is the new icon going BTW ?

[mister p]

Agree......I was using "silicone" as a generic term, Sikaflex is the way to go. Same as with "epoxy", the type depends upon the material.

[Pikey Dave]

When I had the problem with the badly fitted hatch, I used West System epoxy to seal the bare wood edges. It's about £30 for a litre, but will last you for ages if you keep it cool but don't let it freeze. The West Epoxy is thin & penetrates the wood nicely. I'd then add some colloidal sillica to an epoxy mix, this turns the epoxy into a thick putty which is great for sealing holes etc. Ordinary epoxy (aralidite e.g) warns against use in permanently wet situations, West is designed exactly for marine applications.

[Erin]

+1 for Pikey Dave's advice. I would use West System epoxy to seal the wood and then bond your sleeve in with thickened epoxy. You can always finish off with a bead of Sika on the outside edges to be belt and braces. Epoxy will soak into the grain of the wood nicely and is more flexible than some people give credit for.