wood shrinkage

[chris nova]

I'm hoping that I might be able to start on a Shellback project this Fall. However, I don't have a good (warm and ventilated) place for epoxy work so I thought I might construct the building jig and molds and cutout the pieces first this Winter with an eye toward epoxy work in the Spring.

So, my question is, do I need to worry at all about the okoume plywood and/or other parts (2x4's for constructing the jig, mahogany etc. for various parts) shrinking/expanding and throwing off my measurements as I need these parts later in the process? Or is it negligible, especially with the plywood? (I checked the FAQ but didn't find an answer.)

All of this is assuming that I don't want to use epoxy (even the most odorless types) in the basement, even in relatively small portions. Even if I was dumb enough to do it, the wife probably won't let me :-P

[Bob Smalser]

Virginia?

I been using epoxy in the cold and damp for decades without significant problems. Use the cold weather hardener.

I've also used more difficult resorcinol with space heaters in tents and electric blankets. Epoxy is a breeze in comparison.

Seasonal movement in an unheated enclosure? Plywood...no problems. 2X4...no problems. Q-sawn stock...no problems. Flatsawn solid stock greater than 6" will give you problems.

The potential problem with the wood is moisture....the wood will rise from, say 9% now...to say 15% by February or early March. Look up your epoxy mfgr's specs, but epoxy likes wood to be dry, like under 10%.

That doesn't mean I haven't successfully epoxied woods higher than that, but it's risky. Poly glues, on the other hand, adore moisture and will work for you in above-the-waterline applications.

All wood for winter projects I am worried about goes behind household doors come 1 November until I need it:

http://pic3.picturetrail.com/VOL12/1104763/3075040/47003511.jpg

And that's what I would do with your dinghy...spend my available time roughcutting out the pieces and moving the sensitive ones indoors. The strakes will fit behind your couch.

[ 08-27-2004, 04:53 PM: Message edited by: Bob Smalser ]