View Full Version : Help with Moulded plywood repair

07-26-2008, 10:41 PM
My 1956 Yellow Jacket plywood hull had something happen in the past which has resulted in a 4 inch by 6 inch hole/indentation which someone prior to me tried to fix with fiberglass. As I am attempting to restore this as my first boat I was hoping that someone would have a better idea than the rough fiberglass job. It is in a section of the boat that is to be varnished only, so it will be seen! I would be happy to email anyone with the expertise pictures.

Many thanks

Jim Ledger
07-26-2008, 11:09 PM
The best approach would be to post the pictures on the thread directly. Here's how. Google "Photobucket" and create an account (free). Upload the pictures to Photobucket as instructed. Copy the pictures Img code from Photobucket and paste it into the Woodenboat "reply to thread" window.

If you have any difficulty, say so.

Ian McColgin
07-26-2008, 11:32 PM
Find a counter top shop or someone who does that sort of work - overlays like corean or synthetic marble. The industry has perfected a pair of collars that can be fitted over a fine router bit allowing you to use the same template for the cut-out and, changing collar, the inlay. This lets you make a sort of step scarf.

For example, the Thistle I'm restoring at a desultory pace has a metric equivalent of a 1/4" hot molded hull and holes on some of those compound curves. The layers are 1/32, 1/16, 1/16, 1/16 & 1/32 - about. I decided to ignore the fact five layers and go with four - 1/16 each. Working from the outside, I'd make a template for the smallest cut out, the one that goes all the way through. Mostly the templates were light plywood but some curves required wiggle board - a trescool stuff. On bad compound places I'd put slats (protected by plastic) braced from the inside to make a curve for the first layer to lay against.

For the new layers, I found some mahogony doorskin at the dump that was a nice 1/16" thick - try not to pay for veneer if you can avoid it.

Anyway, make templates for the first and second layers - the second and each succeeding cutout being 1" bigger all around than the one before to yield a 12:1 step scarf. Depth control from the second cut out on is most critical. Make sure you get the router perfectly adjusted.

I epoxy in the two deeper layers together with push pins holding it all down. Then the third. Finally the last. I put the layers in inner grain running athwartships, outer bow to stern and middle two ashcroft style at right angels to each other. Make the holes rectangular for ease.

The template will give the true shape you need if you bend it over the hull but the plys might not take the bend going in. Some may need to be slit into slats with an exacto knife and maybe trimmed a little.


07-27-2008, 04:02 PM
A few pictures of the 4x6 inch damage! http://s51.photobucket.com/albums/f386/foothillsfamily/

Jim Ledger
07-27-2008, 04:12 PM
There you go.