3/4 Bass soundpost issue.

Please put any questions about repairing your instrument or the finish on it in our Repairs section.

3/4 Bass soundpost issue.

Postby Mark Wybierala » Thu Aug 23, 2018 5:27 pm

Working on a better than average quality Chinese made bass from a local school and I'm having an odd issue with the sound post. To begin with the sound post looks like it was a hastily crafted replacement. It was fitted too far toward the middle of the bass not quite behind the bridge foot. Even after reshaping the bottom of the soundpost to correct a very bad fit, its still too long but what is actually causing me concern is that its "slippy". Even in its incorrect position where the angles of the top and back are closer to parallel, It doesn't hold very well (the bridge is off and I'm viewing through the end block). Very light pressure on the base of the sound post and it just easily slides and the soundpost falls as if the surface of the back of the instrument was lubricated. To get a proper soundpost position, I'll be shortening it and the angles of the top and back are going to be greater. I suspect that I wont be able to get the soundpost to stand at all. Maybe the surface of the back in contaminated by spray furniture polish like Pledge??? Anyone run into this?
Mark Wybierala
 
Posts: 263
Joined: Fri Feb 03, 2012 10:14 am
Location: Central New Jersey

Re: 3/4 Bass soundpost issue.

Postby David King » Fri Aug 24, 2018 2:34 am

Mark,
I'd try to swab the area on the back with a cotton ball dipped in acetone through the sound hole if you think there's some contamination. You could wet the ball once it's inside the instrument via a plastic pipette and let it evaporate completely before withdrawing it to protect the finish. Maple can become pretty slick under burnishing action of the sound post and perhaps just wetting those areas to raise the grain will reestablish enough friction. Rubbing the ends of the post with a dusting of chalk may also help.
David King
 
Posts: 2428
Joined: Sat Jan 07, 2012 10:01 pm
Location: Portland, OR

Re: 3/4 Bass soundpost issue.

Postby Mark Wybierala » Fri Aug 24, 2018 3:15 pm

Success. Cleaned the inside back with acetone with a bundle of q-tips taped to a stick. Shortened the soundpost by 4mm using bandsaw to insure a good 90 degree side angle and very lucky estimate of the back angle. Cleaned both ends of the soundpost of embedded saw dust with a rag wet with water taking dust out of the end grain. Immediately as I stood up the sound post I felt that familiar grip feel on both ends where it is loosely caught with the ability to control positioning with the soundpost tool.
Thanks David. Now I can work on the real problem involving a neck joint fracture :)
Mark Wybierala
 
Posts: 263
Joined: Fri Feb 03, 2012 10:14 am
Location: Central New Jersey


Return to Bowed Stringed Instruments and Bows

Who is online

Users browsing this forum: No registered users and 3 guests

Your purchase from these sites helps support the MIMForum, but only if you start at the links below!!!
Amazon music     Amazon books     Amazon tools     Rockler tools     Office Depot    

The MIMF is a member-supported forum, please consider supporting us with a donation, thanks!
 • Book store • Tool store • Links •