SCARF JOINT WITH A POWER PLANE?

[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.

[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.

[gdcarpenter]

You mean something like some of these ideas?

[gdcarpenter]

Like this?

[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.

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.

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.

The end result.

[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.

[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.

[bobinpowayca]

Thanks again Bob. I may just see what I can do with my planes.

[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.

[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.