What material for Risers?

[FishStretcher]

It might be worth looking into vinylester for the same reason. It has similar mechanical properties in terms of elongation. And I suspect thinning with styrene monomer would be better than thinning epoxy with acetone, as the material properties should change less.

I can see if I can dig up a reference in my ASM handbook.

Polyester isn't as good, as it is more brittle. Which is why it sands nicely.

Originally Posted by Blue_Heron

If you want to use plywood, and you want it to last, I suggest laminating both sides with glass and use epoxy resin. Polyester resin is not impervious to moisture, and resin without glass in it isn't much better than paint, just more expensive.

Joel Shine, the moderator of this section of the forum, can give you good advice. His business specializes in boat kits with wood/epoxy construction. Done right, it's a good, economical construction method. Or you could post on their forum and ask for advice there (http://forums.bateau2.com/index.php). There are some good guys over there with experience in wood/epoxy that may be helpful.
Dave

[Blue_Heron]

Originally Posted by FishStretcher

... And I suspect thinning with styrene monomer would be better than thinning epoxy with acetone, as the material properties should change less...

Ok, I'm confused. Why would you thin the resin?

[FishStretcher]

Originally Posted by Blue_Heron

Ok, I'm confused. Why would you thin the resin?

To better soak into the wood? Sort of the opposite of bedding end grain balsa. But if you want to seal plywood, you want it to soak in before it gels, (I would think and have read.)

Just remember, free advice is worth what you pay for it.

[flyingfrizzle]

Originally Posted by Blue_Heron

Ok, I'm confused. Why would you thin the resin?

I usually thin my Vinyl ester with styrene and do a good hot coat of thinned resin on the wood so it will soak up the resin better. The end grain especially. Once that is done and kicked a bit then I do the several layers of glass on both sides. If you dont hot coat the wood first the wood can pull (absorb) the resin out of you first layer of cloth and leave some air voids on the face of the wood and not bond as well. Wood will soak up a good bit and if you dont feed it first it will draw in from your lambent. You dont have to thin it but it helps. Just make sure you hot coat it first before you try to lay fiber down on it.

It is just like when you paint wood, the first coat usually soaks into the wood and gets adsorbed by it. The following coats will cover much better due to the wood is now saturated with paint from the first coat. Same with resin, the first coat will get adsorbed by the wood and even better if it is thinned. This helps for 1) to protect the wood against rot 2) to pre-saturate the wood so the resin used on the first layer of cloth dose not get pulled into the wood and out of the cloth. Wood will adsorb nearly anything - water, resin, paint ect. Better with a good coat of thinned resin deep in the wood pours to close off a path for water to get into latter.

[Blue_Heron]

Originally Posted by flyingfrizzle

I usually thin my Vinyl ester with styrene and do a good hot coat of thinned resin on the wood so it will soak up the resin better. The end grain especially. Once that is done and kicked a bit then I do the several layers of glass on both sides. I you dont hot coat the wood first the wood can pull the resin out of you first layer of cloth and leave some air voids on the face of the wood and not bond as well...

Ok. I haven't done much with wood cores. Like you and FishStretcher, I prefer the foam or other inorganic cores. The only times I've used wood, I also used epoxy resin and I didn't have any problems with wet out or bond strength.

[fishmore2013]

I am making slow ground with an unheated garage in cold Connecticut weather, I flipped the cap Sunday-recruited my wife, father in law and fishing buddy. Glassed some spacers to the inner front hull to support the new floor. We had to reglass the top of the hull(someone used a sawzall on it?) to bring that up an inch and straight. More pics to follow.
Thanks again for the helpful posts.

[fishmore2013]

Thanks again for the input, I was wondering if what you thought, I have finished repairing the cap and hull and I will be reinstalling the cap this weekend. I am thinking of glassing the two together that way I never have to worry about a leak there. The only downside I can think of would be if the two needed to be separated for for a major repair?
Jon