Double Bass The Old Plywood Bulge

[beobass]

Can anyone instruct me on how to fix a minor bulge in the back is my bass caused by an excessively tight soundpost? I've fix the soundpost but the bulge remains. Any help would be appreciated!

 

[bassmandan81]

Take off the back, and use a heating pad and a caul to clamp the back back to shape. Sandwich the heat pad between the inside of the back and the caul, clamp the bulge and leave for half an hour so so. You'll need a rheostat or light dimmer to control the temperature of the heat. Be careful to not let it get so hot that it damages the finish.

You can make a caul out of a 12" piece of 2x12 from the lumber store. In your case it will be convex, so sand the corners down until it conforms reasonably well to the back (the desired shape of the back, anyway). A heat pad you can obtain on ebay here:
http://www.ebay.com/itm/Watlow-0601...440?pt=LH_DefaultDomain_0&hash=item51b2a5b5f0
I used this to reform the top of a sagging belly on the top of a couple of Kay basses. Works great, just don't let the heat pad get too hot! Good luck.

 

[beobass]

Thanks!