ad9000 Posted November 3, 2011 Posted November 3, 2011 I recently acquired a very sweet 1966 J-45 ADJ (as seen in avatar). It has a fairly significant sunken top below the soundhole (mostly the result of sitting in a case for 25+ years with strings at tension, I imagine). I had a luthier look at the underside of the top and he was able to verify that the bracing is still intact. It does bother me a bit, but mostly as a cosmetic issue. I'm posting this to solicit opinions on whether I should learn to live with it or try to get it corrected.. Thanks.
EuroAussie Posted November 3, 2011 Posted November 3, 2011 Maybe its just a humidifcation issue ? Sunken tops often means shes' tried out, are there any top wood cracks ?
j45nick Posted November 3, 2011 Posted November 3, 2011 We need some pictures taken at an oblique angle showing both the top and back to get some idea of what is going on. Also, since it's an adj, photographs showing the string clearances around the 12th fret and the height the saddle is set to would be useful. The adj bridge is a mixed blessing. It almost certainly has a negative impact on tone, but it also allows for significant changes in action height that may disguise fundamental problems. Knowing the temperature and humidity the guitar is kept in would be useful as well.
ad9000 Posted November 3, 2011 Author Posted November 3, 2011 Thanks for the replies. Only finish cracks on the top. The guitar has always been in the Southern California coastal area, so no huge variations in temperature/humidity. The adjustable bridge is gone, or at least removed and packed away for safekeeping, replaced by a compensated bone saddle. The neck is straight, action is low. Again, really no playability or structural issues. I will try to get some pictures up later.
onewilyfool Posted November 3, 2011 Posted November 3, 2011 Heavy strings can cause that....also one thing to check immediately is if there is low humidity...check out this article: http://www.taylorguitars.com/global/pdfs/dry_guitar.pdf I once had a girlfriend with a sunken top....
j45nick Posted November 3, 2011 Posted November 3, 2011 I will try to get some pictures up later. If you have any trouble posting photos, go the the "forum feedback" section here. The first thread tells you how to post photos using photobucket.
ponty Posted November 5, 2011 Posted November 5, 2011 Some weeks ago there was a thread where someone was asking about a 'rippled' affect on the top of their J-45. Lots of folks replied saying they had a similar effect. I knew I did. I went to look a my J-45 and was shocked at what I found, and hadn't noticed before! The area above the sound hole on the bass side had a significant depression . Using a straight edge it was easy to the top was concave. When I ran my fingers over the area it was like a dish! According to many on the forum and other sites, lack of humidity was the culprit. However, I live in Bermuda- Average humidity 70/80%. So, without and other explanation for this problem, I got myself a plastic cylindrical medicine bottle and drilled small holes throughout. Filled the bottle with damp cotton balls and placed it it the sound hole, suspended by loose strings. Closed the case. I did this for over a week, refilling the bottle with water and pressing out the excess, leaving the cotton wool damp. I was amazed to see a remarkable improvement, to the point where the top is vey nearly back to normal. So, dryness was the problem. This probably happened whilst I was living in the UK, and I had not noticed. A crack was averted, and bracing is fine. This is the first time ever I have had to do this.
zombywoof Posted November 5, 2011 Posted November 5, 2011 Sinking tops can be caused by a guitar drying out quickly but also, as you suggested, by things like the saddle being adjusted too high to compensate for an improper neck angle. Plus, those adjustable bridges are flippin' heavy - they weigh about three times as much as a "normal" bridge. Pretty much the tops sink and then stabilize. It usually does not affect playability. While humidifying a guitar will help bellying up, I have never seen it raise a sunken top. Even if it did, if the problem was caused by something other than humidity it would just happen again. A good repair guy can flatten a top by using heated cauls or plates and pressure.
ad9000 Posted November 11, 2011 Author Posted November 11, 2011 For anyone still interested, here are some pictures of the top, though I don't think they show the sunken area that well. It is actually a bit more radical than captured in the photos.
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