transom repair-plywood
 

what is the best plywood to use to rebuild transom? Is marine ply the norm? Has anyone used regular plywood and just epoxied it to seal it?

Marine is best, but a few good sheets of regular exterior grade will work, just has more flaws, but same glue holding it together.

don't use exterior grade plywood! it has only 5 plys and many many voids.

if the price of marine grade plywood scares you, use a good 7 ply birch plywood. cabinet grade has very few voids and is about 45 bucks per 4 by 8 sheet in 3/4 thickness.

"marine" plywood is rated as such because of its lack of voids and water resistant glue not because it can be exposed to water. you still have to seal it with resin or it will be toast in short order. the water resistant glue will not matter as you are going to encapsulate it in glass and epoxy.

just my .02 cents but it has worked well for me.

hope this helps, rob

Use a ply panel that is built to a Marine scheduled lay up.
For example a standard Lowe's or HD 3/4 ply panel is a 5 ply schedule. A Marine ply panel is a 7 ply schedule. More lamination the stronger the panel.
A Marine Panel has no air voids (knot holes) in the scheduled layers, standard ply panels do. Air voids are where water can lay or a weakness can appear.
The lamination adhesive is different as well.
A Marine panel is also kiln dried to assure dimensional stability & promote resin adhesion. I would go 1 step farther & get a PTP treated marine panel from Plumcreek or Greenwood products. Same panels just pressure treated then kiln dried again.

I think either Menards or Lowes carries Accruply (sp?) plywood. That has 7 or 9 plus and from what I've seen, pretty much knot free too.
I had same debate when doing my transom and did tons of research here.... Yes, no, ok....
In the end, was going to have a lot wrapped up in the whole thing and decided just go marine grade and be done with it. The $50 more to alleviate that worry was $$ well spent and allowed me to focus on the next worry. :)

okume lasts forever lots of plys light and strong comes from the teak family around 140 150 a sheet do it once do it right

Menards has it. Also called Arauco.

For the transom, just go with the marine plywood if you can find it. It's not that much more expensive than a sheet of Arauco.

Assuming it is a fibreglas boat, pour it in!

ARJAY 6011 POURABLE CERAMIc TRANSOM
Polyester. Successfully being used as a core material in powerboats.

If you don't feel comfortable with ceramic then consider:

Matline CoreMat, Coosa Board and Plascore are generally considered better coring than any plywood.

the transom is the one place in the hull where the wood is MOST of the structural strength. the transom wood is not a core to hold the stringer or deck glass until it cures. it is that which stops your drives from ripping off the boat and sinking, followed shortly after by the rest of the boat. i would stay with traditional methods...

Wish the boat manufactures would worry about the quality of wood they put in the boat when it is first built.Not all but most.Like we do when we build it for the second time.JOHN SR