epoxy help

[dhays]

My epoxy knowledge and experience is very, very old and out of date. What I did know, I've forgotten.

I have had to cut a number of holes in the floor pan of my C400 in the process of installing a furnace. The Catalina floor pans are sandwiched fiberglass. I'd like to seal the edges of the holes against moisture. There shouldn't be moisture there, but you never know. I'm thinking that epoxy might be the best solution. So my questions...

- Is epoxy the best material for this application? If not, what?
- If epoxy, should it be thickened since it would be applied on the 3/4" vertical surface of the raw cuts?
- I'm going for a moisture barrier, so maybe unthickened epoxy with a moisture barrier additive would be better?
- What epoxy products do you use for something like this?

Any other thoughts you may have would be appreciated.

[dbruce85]

A great article from here on Sailnet,

Good luck!

Sealing Deck Penetrations to Prevent Core Rot Photo Gallery by Compass Marine at pbase.com

[scottyt]

actually the best thing is two coats, one thinned slightly the penetrate then another slightly thickened.

use a small amount of acetone to thin, then silica to thicken. dont use lightweight filler as it absorbs or can absorb water.

[imagine2frolic]

Originally Posted by scottyt

actually the best thing is two coats, one thinned slightly the penetrate then another slightly thickened.

use a small amount of acetone to thin, then silica to thicken. dont use lightweight filler as it absorbs or can absorb water.

Which brand, and filler is this? I use the West System, and never heard this ......i2f

[dhays]

Originally Posted by dbruce85

A great article from here on Sailnet,

Good luck!

Sealing Deck Penetrations to Prevent Core Rot Photo Gallery by Compass Marine at pbase.com

Thanks, that is a great article. I've bookmarked it. It provides more information than I need for my currently project, but will help the next time I have to rebed anything.

One question. What about in my current situation where I want to to seal the edge of a large cut out in the laminated pan? There is no practical way to tape off the underside and the volume would be ridiculously large.

[eherlihy]

I recently potted the chainplate holes for the shrouds. I used straight epoxy (MAS Low Viscosity Resin + Fast Hardener). My thought was that it must have a higher compressive modulus than either balsa, or marine-ply, but could not find any thing to support, or refute this.

Can anyone out there tell me if I did well, or screwed up?

[mitiempo]

I would remove the core a little ways. Wet out with straight epoxy, and when it starts to kick fill with colloidal silica thickened epoxy. Acetone weakens epoxy so I wouldn't use it. When hard sand smooth. Epoxy doesn't need a barrier coat, it is one.

[eherlihy]

In the MAS instructional videos, they use a LITTLE denatured alcohol (>5%) to thin the Low Viscosity resin in applications where they want the epoxy to bond well with wood.

Acetone is only used for cleanup.

[scottyt]

Originally Posted by imagine2frolic

[/COLOR]

Which brand, and filler is this? I use the West System, and never heard this ......i2f

the west system fillers are not bad for this. the micro ballons ones can absorb some water but it is a very small amount. the 407 filler is about 40 % perlite, which is also used in soil as a water retention additive, so of all west systems it would be the worst to use.

there are a couple of light weight fillers that are basicly wood pulp, they can be very bad when used in wet places.

to put it simply use the stuff ment for boats and you should be fine. go to some off brand stuff and you may have a problem.

edit as we all know MAS epoxy is good stuff but here is one of their filler, read what it is made of

MAS Epoxies Wood Flour

[eherlihy]

Wood flour is essentially sawdust.