opening seams

[MANDOLINMYSTER]

I've got this 1919 Gibson here, problem is the lower bout,the sides and back have come unaligned, it looks like it may have been reglued at one point but they don't line up. I feel that I can re-aline them with info from another post I read here, just curious about the best way to open the seam with out causeing damage.I would have to seperate the back from tailblock and approx 3 inches out on either side of tail block.Its an unbound back http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif

[Jim Garber]

Not sure what post you are referring to, but take a look at Frank Ford's method (http://www.frets.com/FRETSPages/Luthier/Technique/Structural/CompressionTest/sidecomptest.html) for repairing the problem, commonly know as "Gibson disease" to some. Pretty elaborate but i imagine that it works and holds for a long time.

Jim

[sunburst]

I use a pallette knife. I have some really good old German ones that my mother used to use in oil painting.
A real thin blade like that is what you need. If, as you say, it's been glued before, you might not know what it was glued with and you might benefit from heating the knife, or dipping it in alcohol.
Bear in mind that the finish (if original) on that mandolin is mostly shellac, and heat or alcohol can cause damage to the finish.
I can usually get these things apart with just the pallette knife with no real damage to the instrument. I try to confine any inevitable damage on the stubborn ones to the lining inside the instrument rather than letting the knife get a start into the wood of the back.
A replaced lining, if necessary, is not noticable even from inside with a mirror.

Good luck, let us know how it turns out.

[Bob A]

One luthier of my acquaintance peels the binding off the back, reglues the back without attempting to return it to the original shape, puts in a thin bit of maple to bring the dimensions of the back into alignment with the side, stains it to blend in, and reattaches the binding. Simpler than building the jig from heck, and nearly unnoticeable. Comes to terms with the instrument's ageing process without fighting it too hard.

[MANDOLINMYSTER]

Thanks for the input guys, I think the artist knife with alcohol/heat is the thing I wanted to confirm, there is a section that I can slip a feeler gauge into so I know theres no bond there, thats my starting point. For me I could just take it to a luthier, but its the satisfaction of doing it myself that counts, I hope I'm still saying this after its done!! http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif