5 replies to this topic

[Arnie Eaton]

Building a "Shellback Dingy" and need some 4 by 12 1/4" plywood. I perfer DF and I need just 2 sheets. I'm located in Western Montana and not much pickings in this part of the country. If anyone knows of a source who will ship please let me know. Thanks, Arnie P.S. Must be Ext type and AB would be great.

[Charlie Jones]

If you MUST use exterior fir plywood  buy 3 sheets 4 x 8 , cut one in half and scarf those halves to the other two 4 x 8 panels- Viola! Two 4 x 12 ply panels. well- SLIGHTLY shorter than 12, but close enough.

[Arnie Eaton]

Thanks Charlie, I have 10-12 4X8 panels of ABX fir plywood in my shop. I would love to use them but making a 4 foot scarf seems to me a job that is beyond my skill level. I was able to do one yesterday on 1/2 inch ply that was 22" wide, came out OK, but used a jig and router. The reason for useing cheaper ply is the cost of marine ply. Guess I could jig up a fixture to do the same for the 1/4 ply I have. The plans for the dory call for 10 and 12 foot mag. ply. Big money!

[Charlie Jones]

lol- on the scarfing- got a belt sander? Got a power plane? Got a SHARP ( yeah- SHARP) hand plane?

I scarfed 4 panels the other day as a demo for someone- took me 20 minutes to do the four panels. Wasted away the bulk with the power plane ( a little Craftsman), planed the remainder and finished with 100 grit on a big block. A belt sander with a coarse belt is almost as fast. Or you CAN do it all with just a sharp bench plane, finishing with a block plane.

Once you get into it, it's really easy- just a little sweat equity is all ;D

Get a good solid table. lay out the ply, staggered back each sheet that scarf amount, clamp it all down and cut away. The interior plys will show you how straight it's going. In your case, that would be four layers, all cut at once.

I would say "no sweat" but here that's not true- it's 85 now. ;D ;D But no problem anyway.

Of course, I must tell you- I'm in the camp that says-

"if you are gonna spend your valuable, irrecoverable life hours building the boat, why not build it from top grade materials?"

Your time is worth more than the plywood savings will be and you'll have a lighter, better boat in the end.

But that's just me, after building some 20 boats.

[PAR]

I made this for the edge of my bench to do 8' long scarfs. Some two by stock, a few bolts and a circular saw. It'll make a 2.5" deep scarf in 1/4" plywood, which is a 10:1 scarf.

[Arnie Eaton]

Thanks Par! Looks like an easy jig to make and can be left in place without interferance to any bench work.