Baby Taylor to OM - bridge plate reinforcement questions

[CeeCee_C]

Hi all -

My understanding is that an additional layer of material should be glued to the bridge plate in order to add structure to offset the additional string tension.

In a related article on his site, Frank Ford mentions using a "thin" piece of hardwood.

In a thread on the cafe (http://www.mandolincafe.com/forum/sh...ave-conversion), Paul Hostetter used a "small piece of formica" in his Baby Taylor to OM conversion.

Can anyone (Paul?) please tell me how thick this reinforcement piece should be?

Just because I don't have any formica, what other materials would be appropriate substitutes?

Where would one purchase a small piece of formica, anyway?

Should the reinforcing plate be identical in shape to the existing bridge plate apart from thickness or should it be larger?

Thanks,

[MikeEdgerton]

If you need a small piece of Formica take a trip to your local home store and check out the different brands of laminate used for counter tops (they might not be Formica brand). They have a sample board. Some are larger piece than others. You will obviously need to take that sample home to see what it looks like on your cabinets...

[Jim Adwell]

Formica (plastic laminate) scraps can be had from the trash behind your local friendly shop that makes plastic laminate countertops, cabinets, etc. Or you could ask them.

You could also use a brass plate with holes drilled in the appropriate places.

[pops1]

You could order a bridge plate from Stew Mac for not much money. Thickness would be around 1/8". I would not use the smaller piece of brass, that would strengthen the holes, but not the upward pull of the top that is supported by the bridge plate. I would make it the same size as there is not much of a way to make it larger on most instruments because of the bracing and making it larger on the front where it may overhang won't give any more support anyway. A thin piece of hard maple, rosewood, koa or any hardwood would help. I like them quarter sawed as it is stronger and it may be easier to get a piece made for that application. Anyone with a piece of top or back wood from a guitar that size will also work. Not Spruce!!!

[Paul Hostetter]

I've done this conversion a number of times and it's important to note that the stock bracing for the top is inadequate for the pull of those 8 strings. Martin tenors can take it, but Baby Taylors can't.

My workaround has been to make a slightly larger bridge in that style. A bridge is a brace, after all, and a wider one increases the area the bridge is pulling on, dispersing that pull over a broader area. Using a stock-sized bridge will result in a rather disturbing distortion just behind the bridge.



Four bridgepins or eight—up to you. I've done them both. Four is cleaner.

I recommend a formica bridgeplate patch to a metal one.

[CeeCee_C]

Thanks for the advice, Paul.

How thick should the piece of formica be?

Actually, never having used formica, perhaps I misunderstand. Does it even come in varying thicknesses?

[Jim Adwell]

Thanks for the advice, Paul.

How thick should the piece of formica be?

Actually, never having used formica, perhaps I misunderstand. Does it even come in varying thicknesses?

Not much difference in thickness in various brands, no. It varies between .020 and .030 mostly, occasionally slightly thicker. You could also use Micarta sheets, which come in all sorts of thicknesses if you want something thicker or thinner.

[Paul Hostetter]

Thin normal formica is fine for this purpose. I could mail you some if you like, I have a lot.

[Phil-D]

Plastic laminate (Formica) comes in two thicknesses. 1/32" for vertical applications and 1/16" for counter tops. The samples at your home center will be 1/16".

[Jeff Mando]

Paul, why formica instead of wood? Strength?

[Paul Hostetter]

Yes, no comparison. Believe it or not, the first example I ever saw for such a bridgeplate repair was on a Martin 1-26 from about 1885. The string balls had pulled through the bridgeplate, then through the top, and were pulling directly on the bridge. The person who did the repair (in about 1960) was John D'Angelico.

I used to use model aircraft plywood, but ultimately realized that D'Angelico knew what he was doing. Its extremely lightweight, so it won't affect the sound at all, and it simply won't wear out in less than a century. And the glue you use to affix it to the bridgeplate needn't be very strong (the string balls themselves do the real work) so the repair is easily reversed.

I like Formica way better than any other fix, including the clever but not-very-necessary gizmo with the domed plugs that Stew-Mac sells.

BTW, Phil-D's advice, in post #9 above, is spot on. I use the thinner of the two.

In the case of a conversion from a standard 6-string bridge to a 4- or 8-string bridge in a conversion of the Baby Taylor, you'd need to install the Formica patch inside first, then completely plug the original six holes and prep the gluing surface, then glue the new bridge on, and redrill the new bridgepin holes afterwards.

[MikeEdgerton]

Paul, Do you prefer genuine Formica or can I use Wilson Art laminate?

Just kidding.

[CeeCee_C]

Thin normal formica is fine for this purpose. I could mail you some if you like, I have a lot.

Paul -

Let me see if i can get a piece of the thinner 1/32" formica at my local Home Depot/Lowe's or at the custom kitchen shop very close to my home. If I'm unsuccessful, then I will gladly accept your kind offer.

Sincerely,

[colorado_al]

Four bridgepins or eight—up to you. I've done them both. Four is cleaner.

Hey Paul. Can you give me info on the 4 pin setup? Are the strings held in place solely by grooves in the saddle, or have you made other modifications to the bridge and pins to keep them there? Hard to tell from your picture, but it looks like you've grooved the endpin holes on each side.
Sorry to hijack your thread.

[Paul Hostetter]

No hijacking—this is very much on topic.

No grooves in the saddle! Very important. The strings are guided over the smooth saddle by the string ramps coming up out of the bridge pin hole.

Some people dislike two strings per hole because if one breaks, you have to loosen the good one to get them out and replace the broken one. I personally don't think it's a big deal, I wear strings out before I ever break one. But for someone who typically plays real hard and breaks strings, this is an issue to decide upon.

BTW, slots in saddles make strings break much easier, which is why I strongly recommend against slots/notches, or whatever you want to call them.

[colorado_al]

I am modifying a Blueridge BR40TCE tenor to 8 string octave mandolin. 4 pin bridge looks great and I will follow your design with string ramps from the bridge pin hole. I had been contemplating drilling 4 more holes for bridge pins but thought that might compromise the integrity of the bridge and bridge plate.
I'm also going to reinforce the plate with formica as suggested.
Thanks!!!

[fox]

I also like the idea of using Formica, here is my method of separating the strings ....

[colorado_al]

I also like the idea of using Formica, here is my method of separating the strings ....

Cool. Is that just stainless bar stock? what size? I'm not sure that I can do that as the saddle is very close to the pins.

[fox]

S/S welding rod, I think I used 2.5mm & 2.8mm but it comes in many sizes from 1.5 to about 3.5mm
Yes that does look a bit tight although you don't need to drill deep holes so it shouldn't effect the bridges integrity.

[colorado_al]

PS- What type of adhesive do you suggest for the formica bridge plate reinforcement?
Thanks!

[Paul Hostetter]

Cool. Is that just stainless bar stock? what size? I'm not sure that I can do that as the saddle is very close to the pins.

It's close, but I agree with fox, it should work. Don't let the pins touch the saddle.

But I'd still try the doubled string ramps first.

[fox]

Here is how I have done six string conversions - that might interest CeeCee.....

[Paul Hostetter]

PS- What type of adhesive do you suggest for the formica bridge plate reinforcement?

Normal Titebond or that crummy bottled liquid hide glue. Something light and easy to get rid of. And I clamp and use a caul inside when I drill through the Formica, to make sure I don't push it off.

[Paul Hostetter]

Accidental double post. Sorry.

[Rick Lindstrom]

You guys must be lucky. The last time I tried to source some formica scraps (the cabinet guys call it "mica") nobody had seen any in years- they had all gone over to preformed (or whatever they call that stuff) counter stock.

I'd be very surprised if you can find formica at Lowes or Home Depot, but if you do, let me know. I'm still looking for scraps.