Having recently re-inherited a 1980 Hummingbird that I'd given my younger brother in 1985, I'm in the process of reversing thirty years of damage. I have always done the basic work on my own guitars and am quite comfortable with taking on this project despite not having served an apprenticeship with someone.
The odd paddle-shaped dovetail neck has been steamed off and I've decided that I could do a more thorough repair of the damage by removing the back to perform a series of repairs to the bracing and bridgeplate....both have failed leaving a bellied top and a bridge that slants drastically toward the sound hole. There are thankfully no cracks on the top or sides (small miracle) but there are four smaller grain cracks on the back that can easily be cleated after bringing the guitar back to a normal humidity level (it was never in its case, I'm told). The guitar neck was reset at one point and definitely needs to be reset properly as well as refretted (I've done refretting several times).
I'd greatly appreciate advice on the best and cleanest way to remove the back with the least amount damage to the finish. I have seen many tops removed online but none to a guitar with the synthetic binding and purfling that gibson uses. I've made a template of the back out of 3/4 mdf to make reassembly easier and think that I have all of the tools needed to do this job, whether using a squared point "shoe knife" (seam knife) to separate the binding from the sides, or possibly another way.
I'd considered working on the guitar through the sound hole originally but believe that I could improve the overall sound of this overbraced "Norlin" by scalloping and tapering some of the existing structure while in the process of repair and regluing.....I might be too optimistic....but I'm not afraid of trying.
Thanks for any and all advice......
Thanks Dave, I totally agree. Ren Ferguson took over Gibson's acoustic division in Montana back in the eighties and, more or less, resurrected them. He went down the line, one by one, analyzing all of the guitar specs and in many cases returning the bracing patterns back to their "heyday." He even got to examine and document John Lennon's 160E so that they could produce a faithful reissue. I don't know if they did this for the Hummingbird, but I happen to know him through a friend and can find out. Everything about this guitar is technically sound (except for the chewed up spruce under the bridge....awaiting some attention very soon. The bracing, as you can tell in the picture above is a bit overdone. I want to improve the sound, if possible, and let the animal resonate a little more. Nice spruce, clean mahogany, and very straight maple neck....no surprises there.
My two-cents would be to keep the back off for as short of a time as possible. The sides, over time, will lose their "memory" for the back and shift-around slightly and not noticeably... UNTIL it's time for the back to be reglued and then there's hell to pay with alignment :)
PS: yes, I discovered this the hard way!
Yes, Mike has a very good point. For myself, I made some of the L-shaped alignment brackets, described by Frank Ford, used to adjust the alignment of the sides to the back(he describes using them to realign the distended sides of a teens Gibson mandolin). My brackets have repeatedly useful in these situations.
Fortunately I made a template out of 1" mdf and fit it on the body snugly before I removed the back. I've notched the perimeter of the template every three inches to allow for the spool clamps to go through. This allows me to leave the template on the guitar until after the glue has set and hopefully the back will behave. I've got a lot of work to do on the bracing and bridge areas.
Thanks for heads up, Mike....I know that thin wood has a mind of its own.