About to glue on the back...

[sorengyllstrom]

... and then I noticed that it fits perfectly all the way around the sides, but there are a very thin (<1 mm.) gaps between the back plate and the heel and tail blocks. Probably screwed something up them sanding those parts to accomodate the radius of the back. First build issue, I guess...

How do I solve this? Make some teeny wedges that I can glue between the blocks and the back, or should I sand the whole thing down with my sanding stick and live with the slightly thinner body?

Best regards
Søren

[MaineGeezer]

It looks as though you are doing a beautiful job.

I would jusr sand the sides down a bit adjacent to the end blocks so there is a smooth transition transition and no abrupt step or local depression. In fact, less than 1 mm may be ignorable if it pulls down smoothly when clamped. . Yyou just don't want the blocks to be localized in low spots.

I am assuming you have sanded the blocks to the same radius as the sides? How did the end up low?

Or does the back touch the blocks on the outside edge but not on the inside edge?

[sorengyllstrom]

Thanks for your reply! I think I might have cut the blocks too flush and just not paid enough attention when sanding the sides to radius. I must have assumed that it was ok ;) I think Ill carefully sand down the sides to avoid an uneven dome on the back or the risk that it cracks if I try to force it down with a clamp when glueing.

Best regards
Søren

[Diane Kauffmds]

I would chalk the the sides and block and sand a bit, so you can see what's coming off. A little sanding and you'll be fine.

[sorengyllstrom]

Thanks!

[ruby@magpage.com]

I would argue that the back does not have to touch the entire block, just the outer portion enough that when you create the channels for binding and purfling there is still a bit of glued surface.

I think 1/4" of glued surface would be enough - that is about the same as the rest of the plate/side joint where the linings create the gluing surface all around the perimeter of the instrument.

I have seen a couple of instruments where you could see the shape of the block in slight distortion of the back plate.

Ed

[carld05]

I've purposely beveled the inside of the blocks to establish a glue edge the same widths as the linings like Ed suggests.