Scarf joints

[Desert Jay]

I'm near the point where I'm thinking about the scarf joints. I'm a bit worried about ugly and unsafe joints. I'm a pretty good swimmer but it would be so embarassing... Anyway, I know Dave built a jig- I went to the site from your blog on the jig's construction. But it's one more task to do before actually building the boat. Is scarfing that difficult with a block plane? Anybody have any advice or experience?
Thanks,
Jay
(I think I'm worrying more about this boat more than I did raising my kids!)

[JonLee]

If you are experienced with the plane, then no, it really isn't that hard. If you aren't sure, find a couple of scraps of plywood and do a practice run. If you don't like the results, you can either practice some more, or switch to the jig.

[Donm1753]

It's not that hard, but you need to learn how to sharpen your plane blade first. It has to be razor sharp to cut across the grain without tearing it out. I prefer a larger plane, like a jack plane or smoothing plane to a block plane because it has more mass behind it. The angle of the cut can be judged by the distance between the plies. If the distance between all the plies is about equal, then you have a constant angle. If one or more plies is thinner than the others then you need to remove more material. I agree with practicing first on a few scraps. I found it easier to rip the plywood to the approximate width of the panels before scarfing, but some people scarf the panels full width to save a little material. You may also want to start with the bilge panels. Although they are wider than the other hull panels, they are also shorter. So if you mess up a scarf you still have enough combined length to cut another scarf in the same panels.

[joebd5]

I built a plywood scarfing machine from the plans from Wicks Aircraft Supply in Highland, Illinois. It works great and is almost idiot proof.

[JonLee]

Maybe I should try that...I'm an almost idiot.

[Desert Jay]

I did my first scarf joint and it worked great. I chose not to make a jig. I just staggered several pieces of plywood (ratio appropriate spacing based on the thickness of the stock) and they sort of built a ramp. Then I used a block plane and it went quickly and smoothly. I practiced on some scrap wood first but the second try was for real (for the keelson) and it was easy. I used the larger plane occasionally but most of the work was done with the block plane. No sanding. This is a good article on scarfing: http://www.duckworksmagazine.com/07/col ... index3.htm See figures 8-16 and 8-17 in the article for a good view of the stagger and planing. I'll be moving to the hull next (I never thought I'd write those words) so I feel a bit more confident joining those key pieces.
Jay