Routing a caul for gluing up a rounded corner

[Vince Shriver]

How to route out a "negative" circle to fit exactly against a rounded corner. I'm gluing laminate edging on a 1-1/2" thick table with carpenters glue (not contact cement) and I want to clamp a caul against the plastic at that corner. I know there's a way to do this with a router. Thanks, Vince

[Walter Plummer]

I think a band clamp would be a much better and easier solution. If you really want to go with a caul you need to figure out the radius of the table corner. Set the distance from the pivot pin to the far side of the router bit and rout the curve. In other words subtract the bit diameter from the table radius. Someone else may explain it better.

[Jim Morgan]

Cut your profile on a piece of 3/4 whatever. Mark the profile on enough additional pieces of 3/4 to make up the width you need; cut out most of the waste. Sandwich the profile piece between two rough pieces, glue up. When the glue is dry, use a pattern bit to trim the rough pieces to the finished profile. Lather, rinse, repeat.

[Vince Shriver]

Thanks Walter. I finally found an illustration of what I need to do. Your explanation is right on and very clear. Because the band on the "Merle Clamp" I have is only a 1/2" wide and my edging is 1-1/2", I want to apply equal pressure to the entire surface of the corner. I will use the band to clamp the caul to the laminate, however.

[Jim Becker]

If you line the caul with some leather or similar, you can be "close" on the corner contour without being "exact" and get good clamping performance. The leather is hard enough to not crush while still having a little bit of give to make up for any fit inconsistencies. It also doesn't mar the surface, either.

[Vince Shriver]

Thanks Jim; oddly earlier I was thinking of what would be a good material too use just as you suggested, carpeting pad, cardboard, and on and on. Leather would be the trick - great suggestion.

[Mike Henderson]

Thanks Jim; oddly earlier I was thinking of what would be a good material too use just as you suggested, carpeting pad, cardboard, and on and on. Leather would be the trick - great suggestion.

I've used 1/4" thick cork for these kind of situations. But carpet padding should work well, also.

Mike

[Jamie Buxton]

Leather is flexible, but doesn't really squish very much at all. A little bit of squish is what is needed to fix irregularities in your forms or substrate. A better material is sheet flexible polyethylene foam sold as a packing material. It is closed-cell foam, so it does squish a bit. For instance https://www.amazon.com/DAT-Cushionin...b-57e6118a3951