Official Luthiers Forum!

I'm finishing up a cedar OM, so maybe I'm just sensitive. But I keep hearing horror stories about bridges coming off and taking chunks of the top with them.

I normally use a razor blade to scrape finish off the footprint, and then use hide glue with the LMI vacuum attachment.

I wondering if I should paint the footprint with diluted hide glue to stiffen it up before I glue the bridge on.

Any thoughts?

And, as always, thanks in advance.

Steve

As long as you don't cut into the fibres you should be fine with your regular procedure...

Generally, the problem can arise from one of two causes. As Ed said, if you cut too deeply while scoring the finish around the bridge, there's a really good chance that the fibers will tear loose when the guitar is tuned up to pitch. The other is if there's a serious amount of grain runout on the top. Spruce is a more forgiving , but redwood can exhibit the same problem as WRC. As long as your careful when scoring the finish, you should be all right.

_________________
michael propsom
www.propsomguitars.com

I'll concur that there's no need for glue sizing on straight grain. Now if it was curly redwood, that definitely should be pre-coated to clog the exposed endgrain.

I've made lots of cedar tops and treated the bridge gluing operation same as I would on a spruce. No problems to date.

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

It helps a lot to make the bridge wider, so that the distance from the front to the back along the line of the string pull is greater. This reduces the maximum stress along the back edge of the bridge. Since cedar is not as tough as spruce, having, in particular, lower peel strength, this helps keep the problem from getting started in the first place. That's the principle behind the 'belly' bridge: it's not so much greater surface area as it is a larger distance from front to back. To avoid ending up with a too-heavy bridge I often use lower density woods for the bridge on cedar tops.