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Gluing pre shaped back pieces?

Posted: Mon Feb 07, 2011 2:54 pm
by Haggis
Hello
If the 2 pieces of the back are pre-shaped, as they are in my martin kit. What would be the best way of joining them to get even pressure along the seam? I have made a fixture and 2 small wedges that should force the pieces together(with the back strip between them) Is it enough with 2 wedges? I would prefer to have one more wedge at the waist area, but can“t find a clever way of getting support for it there because of the reversed curve.
thanks
Haggis

Re: Gluing pre shaped back pieces?

Posted: Mon Feb 07, 2011 4:17 pm
by Freeman
What has worked for me is to put the two piece together on a sheet of plywood. Clamp to piece of wood maybe an inch thick to lightly touch the upper and lower bouts. I put a yardstick where the center seam will be, then a piece of waxed paper on top of that. Coat the seam with glue, set it between the 1 inch boards and push it snuggly against them (there will be a wedging action). Clamp the outer edges of the upper and lower bout to the plywood next to the 1 inch pieces.

Now pull the yardstick out and push the seam down to the plywood - that will snug it just a little tighter. A piece of waxed paper on top, then a board down the center seam clamped to hold it down. Takes longer to type than actually do it. Works with a center backstrip too - must make sure it is pushed all the way to the plywood - sometimes they are a hair thinner than the backs. A little scraping and you're ready for bracing.

I assume you've shot the seam really well.

Re: Gluing pre shaped back pieces?

Posted: Mon Feb 07, 2011 5:42 pm
by kencierp
Ditto Freeman ---- this is the tried and true "Irvine Sloane" procedure I've used many time with success. The one change I'd make is to use regular clear packaging tape for the non-stick release paper (easier to handle than wax paper) -- I have yet to find any glue that will adhere to that kind of tape.

Re: Gluing pre shaped back pieces?

Posted: Mon Feb 07, 2011 6:04 pm
by tippie53
http://www.youtube.com/watch?v=3asM32m0S1U
if the back wood is mahogany don't use the CA but you can see how the tape clamping works on this vid