Transom replacement

Over the past weekend I was able to pull the old dry rotted transom plywood off my 14' Starcraft look-a-like. I was able to keep most of it intact to use as a pattern for the new one. The old transom was 1 5/8 (1.625) thick marine plywood. Does anyone know where I can find repalcement marine plywood in that size? Using a solid 2 x 8 cut to size is an option but the thickness, or lack of it, leaves a gap along the transom shelf and inside the transom aluminum cap rail.
Mike

Go buy some exterior rated playwood (NOT pressure treated) that you can laminate together to come up with the 1 5/8th you need. After cutting all the layers needed to shape/size, put 2-3 coats of spar varnish on each piece. After the last coat is dry, glue them all together to form a single piece and install it in your boat.

Kind of what I had in mind to do but will have to travel because this small town only carries 1/2 and 3/4 plywood and you don't get to 1 5/8 with those. I also plan to use a 2 part epoxy like the West Marine stuff to seal it. Anyone have any recommendations / experience with using two part epoxies to seal the transom wood and wooden bench seat tops?
Mike

If you think about it, 2 layers of ¾" only leaves 1/8th for X number of layers of waterproofing and epoxy so that should get you close enough to work. If you went with 3 coats of spar varnish on each piece of ¾, that would be 12 layers thickness of varnish and one layer of epoxy by the time it was all assembled.

JMichael a very good point and one that that will make it an easy job. Joining the two 3/4 panels together with Titebond III then coated with multiple layers of 2 part sealing epoxy I should be very close. Drill the new holes for the hardware, coat the inside of the holes with epoxy and once dry install the new hardware coated in 5200. Should work really well. Thanks

I used the West Marine 105 epoxy on my transom replacement. It is easy to use. ( I bought the pumps for the bottles. It makes it easy to dispense just the amount you need in just the right ratio. ) It applies like a thick varnish. Be sure to drill your holes oversize and coat the insides with epoxy too. I used Titebond III waterproof glue on 2 layers of 3/4" exterior grade, then coated with 3 layers of epoxy. You will need to use a UV coating over the epoxy, as the 105 does not have UV protectant in the epoxy itself. Spar urethane (I used Helmsman brand) works well if you want the wood to show, which was what I chose. If not you could paint over the epoxy once it cures good (several days). The epoxy easily added over 1/8" thickness to mine. One last thing, be sure to saturate the edges of the plywood well and fill any voids with the epoxy.
Hope this helps. You can see below:

When I replaced the transom last April of my 1956 Arkansas Traveler (1st time for that boat), I used the old one as a template. I glued 2 different sizes from Home Depot to get a close match in the plywood thickness. The hardest part was grinding and drilling out the old rivets. Nuts and bolts were used to replace the rivets.

Thank you all for the replies. I plan on using the exact procedure that you used Ringo with the addition of 3M 5200 on the transom hardware. Still have not decided on painting or leaving the natural wood but I'm leaning towards the natural wood. I figure when the outboard is clamped on it will tear up the paint anyway and with natural wood the marks wouldn't be as obvious. Thanks for the photo Ringo you do nice work.
Mike

Install a piece of aluminum over the wood where the motor will clamp. That keeps the clamps from damaging the wood and breaking the water sealant. Even though my wood is not exposed, I used a thick piece over mine to keep from damaging the wood.