Official Luthiers Forum!

I need some help in an area that I have no expertise. I have two instruments being re-finished for me and I just realized the bridge plate on a six has to come off. This is what happens when you build an instrument over 6 years and have a touch of
I built the box for this GC a few years back and did a box for a 25.34" neck and 4 years later built a 24.9" neck. I would rather keep the 24.9" setup.
I drilled a couple of holes where the bridge pins would go and the plate front extends only about 1/4" the in front of the holes. Lots behind the bridge, so I have to pull it. As the top is paritally finished, I could sand some if I bake it a little with too much heat, but was looking at a heat gun heated small spatula to work it off instead of Frank's doubled over file setup on Frets.com. I think there is enough room to get the spatula in.
My problem is I am nervous about the top center glue joint. It's HHG of course, but I don't like getting heat near a solid joint.
Can anyone help an old man across the street?

Maybe 2 clothes irons on the top , one on each side of c/l, but not touching it. I still think someone needs to make an electric spatula.

I see StewMac has a plate removal chisel now.

http://www.stewmac.com/Luthier_Tools/To ... hisel.html

I bet Ron or Marty would have some good ideas.

Good luck! I have never had to do it. Let us know how it goes.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

Hey Haans Happy Holidays to you!

We use cartridge heaters inserted in aluminum cauls that we made just for this purpose. Our spatulas are repurposed putty knives that the corners have been ground rounded and the entire blade has been heat bent 180 degrees. Same idea as the Stew-Mac offering but a broader blade, no pointed edges, and much less cost.

With these tools and a repeated heat a bit, work the knives under something of the plate, repeat using time and of course if the glues were serviceable as they always are in your case the plates come off.

There is a HUGE risk of splitting the center seam and HHG is a possibility if over heated. My suggestion is to use repeated sessions never over heating at one time and taking the time to get good with the tool. Any pointed edges can catch and mare things up so smooth and polish the putty knife and it will pay off for you.

It's cumbersome working in the sound hole and the larger your arm the more problematic it will be. I've seen some pretty good Luthiers split a center seam so you are correct this is always a possibility. This is also one of the reasons why I push unslotted pins at every opportunity to builders and I used them myself. Bridge plates should be serviceable and installed with serviceable glues but you are right the proximity to the center seam of the top makes them a joint that you really, really don't want to ever have to service if it was avoidable as it is with unslotted pins. This is not directed at you I'm just a freakin broken record....

Good Luck.

You could just add a bit more plate in front and call it a day. When you look at how shoddy some of the major manufacturers bridge plates are it's hard to get too excited about one that is slightly misplaced.

What about leaving well enough alone? The ball ends won't pull through, and the bridge-top-bridgeplate sandwich will still function as a unit. It would sure be better to leave it than to mess up the completed box. I'm pretty sure that lots of manufacturers whose work you emulate would have let sleeping dogs lie, and just completed it. It certainly wouldn't be the first guitar with an offset bridge plate.






oops, Clay beat me to it while I was agonizing whether to post or not. Ha!

I might do a cost/benefit analysis and grudgingly come down on the 'maybe leave it' side as well.

With the plate behind the bridge, it should prevent forward roll nicely, while still catching the ball ends.

I'd wonder if that plate really, really, needed to come out. What are you gaining vs what you are risking...

I would be thinking of leaving it too. I bought a hand-made parlor guitar on ebay. When I got to having a close look at it I found that the bridge plate is misplaced - much as you describe, but even worse because the pin holes are right on the edge of the plate. It annoyed me to know it "wasn't right", and I spent a lot of time plotting to remove and replace it. But it looks nice and plays well and all of my friends who are players and not builders say I would be crazy to mess with it. They don't see it as a problem. Who is correct - I don't know? But it seems that as instrument builders we might sometimes have a degree of perfectionism which is unnecessary and counter-productive.

Maybe consider it an example of wabi-sabi. Or possibly it will turn out to be an accidental tone-enhancing design improvement. Tell people it is your patented "rear-shifted tone plate" and charge more for it if you plan to sell

I don't know that I'd lose a lot of sleep over there only being 1/4" in front. My advice would be leave it alone and service it should this ever become an issue. Like in 30-40 years... from a few photos I've seen of your guitars (beautiful by the way), I suspect it is a small box (small sound hole?) and this might be very very difficult to accomplish.

If you are set on replacing the plate, I would not be too concerned on the center seam given the guitar is unfinished. If it separates, you will wick in thinned HHG, treating it just like a split center seam repair if a guitar came into the shop. A light scrape and sand, and you are good for finish. Good luck to you.

Andy

Put a damp sponge on the bridge plate overnight, it will really help loosen the glue up when you and heat the next day. John Arnold provided me with that tip after I split the centre seam by using too much heat.

Thanks everybody. I have been re-thinking today and trying my best to place the BRW plate on the top.
Bridge is typical 1x6" pyramid. Pins are about 1/4" from rear of bridge.
Looks like the plate is about 1/8" forward of pin hole on the treble side about 1/4" forward on the bass. That means the plate sticks out behind the bridge about 3/4 of an inch and is just about 1/2" short of the front of the bridge. My best thoughts are to add about 1/2" to the front of the bridge plate. That would make it 2" wide total.
Then I could mask off the spruce on the inside and take a small block of 60 grit, get inside there and taper the back of the plate as much as I could...say a movie's worth. Biggest problem is, it's the LAST Grand Concert I will ever build.
Actually, thinking about it, the plate is in the place that the box was designed for, but the bridge is about 7/16" forward of where it should be. I guess I can always sand the back of the plate after it's been played some. Not worried structurally at all because the bridge is within 2" of the X, and the X braces are laminated red spruce/BRW.
Would be a good experiment to see if it even matters much.

That's some serious carbon fiber!

"That's some serious carbon fiber!"

I think that's some BRW you are seeing - Larson style.

And really - it probably doesn't matter much. I am sure the rest of that thing is beautiful!

I had a repair come in where a guy built the body for a long scale and used a pre made short scale fretboard. The holes for the high and low e strings went through the X brace. Are you OK in that department?

Just thinking, maybe you could locate and tape the bridge in position and drop a 3/16 or smaller. neodymium magnet in the holes and see where another magnet inside lies on the plate.

I’ve got some I thlink, I could send you a couple.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

It is BRW.
Terry, I'm good, thanks. The holes miss the X by a good half inch on each side. Larson's have that wide X. My biggest worry is the 3/4" hanging behind the bridge restricting tone production. The front of the bridge plate is roughly where the saddle will be. So, adding 3/8" to 1/2"will probably do the trick. We'll just have to see how it plays out...

I added 3/8" to the front of the plate. Still sounds pretty good, so I am hopeful...