Best thickness for gluing back/tops

[Dave Bagwill]

What is the thinnest that you would recommend for joining a top or a back? I think it was Ken who cautioned not to get thinned to final measurement before gluing, but to leave plenty of thickness for the glue joint and thin afterwards.

Anyone have recommendations for spruce, for red cedar?

[Tim Benware]

I figure about .005" more than final thickness.

[Herman]

Dave
I always glue the plates as thick as possible, after sanding the sawmarks off, and thin afterwards.
A minimum thickness therefore is not what I can advise. So sorry Dave.
With the specs Tim gives I would say: clamp precise and flat as possible.
Good news: You can saw the top in two and start over again if you mess it up. Ha!

In my upcoming project, a gypsy guitar, I have to glue the bended top, after sanding to about final thickness. 2.1mm/0.084"!
Talking about a challenge!
I guess I make a profiled caul to clamp it to. Otherwise I think we will encounter a misadventure.
Thinking about making a log on that one.
Greets
Herman

[Dave Bagwill]

Log it, bro!! That would be a worthwhile addition to the forum for sure..

[John Parchem]

I glue as thick as possible. I do sand the plates to remove saw marks as it is needed to do the tap evaluation of the plates. I am happiest when I have a mm or 2 extra when joining.