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SCARF JOINT WITH A POWER PLANE?

Posted: Tue Oct 08, 2013 11:13 am
by bobinpowayca
Howdy, I'm building the Geronimo. I bought a Bosch power plane and used it for fairing the keel and chines (finished with planes) and it worked really well. I'm wondering if anyone out there has used a power plane to make scarf joints on 3/8" marine plywood - how you did it? I can't find any plywood longer than 8' around here but I'll bet with a power plane you could do a pretty fair job.
runabout 033.jpg

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Tue Oct 08, 2013 11:53 am
by slug
I had considered trying it, but would have to build some fairly elaborate ( large) jigs in order to span the four foot width. You would have to mount the planer on a 45 deg. angle to cut without too much tear out and have really sharp knives.
The ply would have to be screwed down to keep it flat ( same when using a ski saw), then you get into the issue of raising or lowering the planer for progressive cuts.
Seems like a headscratcher to me.
Might be simpler to try it with a router instead ( adjustable height cuts at least )

Doug

Building the Gentry, sailing the Titan.

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Tue Oct 08, 2013 12:09 pm
by gdcarpenter
You mean something like some of these ideas?

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Tue Oct 08, 2013 12:12 pm
by gdcarpenter
Like this?

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Tue Oct 08, 2013 2:07 pm
by rbrandenstein
I built a jig out of MDF for my Makita to scarf my plywood.
The plane sits an angle to the cut to reduce tear.
IMG_0309.JPG
Bottom view. The guide on the left is angled to match the scarf. It attaches as a replacement base plate. It must be routed out to match the cutter height.. e.g. the cutter must align with the base of this jig.
IMG_0412.JPG
In use. The plywood being scarfed is clamped to a piece of guide plywood that is the same thickness (I think 3/8") as the guide bar on the jig.
It takes repeated passes.
IMG_0414.JPG
The end result.

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Tue Oct 08, 2013 9:15 pm
by bobinpowayca
Thanks a lot Bob and gdcarpenter, I'm impressed with your skills at designing jigs, looks a little beyond my skill level frankly. I was thinking it would be a lot simpler, guess I'm missing something. I'll study them.

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Wed Oct 09, 2013 7:50 am
by rbrandenstein
Others have made successful scarf joints by just using a hand plane and sanding block.
You could also use a belt sander, but without some jig you could easily over do it.

By using the ply lines as guides, it isn't too difficult to eyeball a decent joint. Even spacing and parallel lines will show you the way. Epoxy with some filler can fill-in minor variations.

Take some scraps and practice various methods. It isn't as hard as you might think.

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Wed Oct 09, 2013 10:44 am
by bobinpowayca
Thanks again Bob. I may just see what I can do with my planes.

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Thu Jul 13, 2017 11:34 pm
by Catbldr
I saw a really nice jig setup for a circular saw . Basically setting the circular saw at 6 degrees above zero degrees with the saw perpendicular to the floor ( or at 84 degrees precisely). The saw rides on a guide that holds the blade just touching the edge of the jig. With the jig five feet wide you can make a clean scarf for four foot wide plywood. If the scarf is wider it can be started here and finished with a hand saw held flush and sawn through. Im making two, one at six degrees and one at seven degrees.

Re: SCARF JOINT WITH A POWER PLANE?

Posted: Thu Jul 13, 2017 11:37 pm
by Catbldr
I saw a really nice jig setup for a circular saw . Basically setting the circular saw at 6 degrees above zero degrees with the saw perpendicular to the floor ( or at 84 degrees precisely). The saw rides on a guide that holds the blade just touching the edge of the jig. With the jig five feet wide you can make a clean scarf for four foot wide plywood. If the scarf is wider it can be started here and finished with a hand saw held flush and sawn through. I'm in the process of making two, one at six degrees and one at seven degrees.