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View Full Version : Bridge patch thickness and material?



cml
08-28-2016, 07:12 AM
How thick do you all make your bridge patches, and what material/wood do you use?
I plan to use a cedar top, and I could either use cedar, spruce or maple for the patch.

little timber
08-28-2016, 08:33 AM
I use maple often. usually cut-offs from backs and sides. they tend to be ~2mm

sequoia
08-28-2016, 06:18 PM
Mine are about 2.5 millimeters on a tenor top. You know, not too thick and not to thin. 2 mm is probably fine too. Not sure the thickness is terribly important... What is important is that the grain orientation is perpendicular to the grain of the top creating a ply. Strength is important here to counteract the tendency of the bridge to dip forward under string pressure and deform the top which can lead to changes in compensation and string height.

As for wood type, I'm not sure this is a big deal either. My thinking is that like should go with like since they will expand and contract more or less the same. Shrug. I have used spruce with spruce, mahogany with mahogany and myrtle with myrtle and it seems to work. I've used spruce with redwood and that was fine too. Maybe the main reason is that when I thin the top, there are handy thinned pieces of cut-off wood available which make great bridge patches with the least amount of work. My sneaking suspicion is that anything probably works fine other than balsa wood rubber and we can chalk this one up to OUBS (obsessive ukulele building syndrome) of which I am frequently guilty.

cml
08-29-2016, 01:57 AM
Thank you both, I'll see if I cant get a nice piece of cedar from the top. Failing that I've got maple ready.

Jardin
08-29-2016, 09:48 AM
I just wanted to add that if you are planning to use a bridge that has strings going through the top (bridge pins or pull-through style) you may want to consider a hardwood bridge patch as this will prevent denting and eventual pull through.....if using the classical guitar type bridge or the old school slotted type....its can be any of the above...

sequoia
08-29-2016, 07:38 PM
I just wanted to add that if you are planning to use a bridge that has strings going through the top (bridge pins or pull-through style) you may want to consider a hardwood bridge patch as this will prevent denting and eventual pull through.....if using the classical guitar type bridge or the old school slotted type....its can be any of the above...

Excellent point and valid. Since I just use a classical guitar type bridge the density of the bridge patch is not an issue. If I was to use pins or pull-through style I would NOT use spruce or cedar and would use a hardwood like mahogany or even harder. I have a friend that has an uke that has worn holes through the bridge patch and it is a serious problem. It is an old Martin soprano circa 1920 and probably has a mahogany patch (I don't know). But still the thing is almost hundred years old and is allowed to fail.

Michael N.
08-29-2016, 09:34 PM
I think a bridge patch would need to be considerably larger than the bridge to counteract any distortion in the soundboard. It's under a rotational force, commonly the soundboard dips ahead of the bridge and humps just behind it, often observed on old instruments. A straight fan brace in line with the centre joint will have much more effect than any bridge patch. I've made countless instruments without a bridge patch and the soundboards have held up, at least the couple that I've seen that were made 30 years ago. Of course you might want to include a bridge patch for sonic reasons but they certainly are not necessary for structural ones.