Got a repair. Opinions?

[nnickusa]

Mate has brought me this guitar, which has a lifting bridge. He's had it in to someone for repairs, and has had a few cracks repaired, the top is bellied, and that wasn't addressed. at the time. They did, however, talk him into having a poly finish laid over the top, thereby making it stronger. Not sure I buy that, but it's done and I'm not going to address that issue either.

I've looked inside and all looks pretty solid and stable, so I'll not muck around in there either.

I'm thinking hot knives to remove the bridge, re-profile the bottom to fit the top properly, and glue the bridge back down, probably titebond, altho I have fish glue as well..

Does all this sound OK to the repair gurus here?

[ozziebluesman]

G'day Nick,

I'm no guru but I reckon that seen the corner of the bridge is lifted it is just a matter of heating it up and getting a thin flat knife under there and steadily part the glue joint. In my restoration of the Jumbo guitar somebody had used epoxy to glue on the bridge but it came off but it took me three hours. I would then stablise the guitar in a controlled environment at 45% humidity for a few weeks and the top may come down a little. Clean it all up on both surfaces and glue it back down again with Titebond.

I don't like the idea of a a poly finish over the top either as I think it would impair the tone for sure. I was thinking maybe the guitar lives near the sea maybe?

Just my thoughts Nick and there are plenty of others here who may have a better suggestion.

Good luck with the repair.

Cheers

Alan

[Tod Gilding]

This is the problem with building guitars Nick your mates start bringing you repairs

I find that if you turn off the lights and be really quiet sometimes they go away

I have just finished this same repair (I wasn't quiet enough ) but I have a very thin flexible scraper that I left touching an electric stove element and when the scraper was hot it slipped under the bridge through the HHG very easily the area around the bridge was masked very well and any HHG that remained on the bridge and top came off with hot water I used HHG again and the repair has been good.

also Shirlock Hamley has me wondering now why he thinks this guitar lives near the sea

[nnickusa]

Alan, that was my approach. under tension, the bridge evidently has plenty of lift, so it ought to be plenty easy to get off. Then, RH control, as you suggest(my dry room now sits40-45% RH without any further interference from me--thank goodness). Titebond, as I'm most familiar with it....after re-fitting the bottom of the bridge to the new profile of the top....that is, snad paper and rub the base of the bridge on the top.....like fitting to one of my guitars...

Tod,,,,mate, at least this time he's willing to pay me for the help. Been doing little "favour" for a while....He's a nice bloke, and I'm always happy to help anyone out. I don't mind doing a repair or two along the way, as I'm sure not making any cash building...

Happily, pizza is a popular food choice....

WIll update, as appropriate.....Thanks..

[ozziebluesman]

Good on ya Tod.

Usually when an acoustic guitar bellies severely it lives in a wet environment. My son lives on Magnetic Island which is just a twenty minute ferry ride from Townsville and the humidity there really plays havoc with his guitars. He has a Maton and a Takamine acoustic and a dready I made him that will hopefully survive the wet conditions. A small drive away from Townsville is the small town of Paluma in the Paluma Ranges and I have seen the same thing happen to guitar tops from that area. Tully further north a bit is one of the the wettest areas in Australia and I have seen numerous guitar from there that have bellied severely and cracked tops. So I thought maybe Nick's guitar repair may live near a sea breeze too!

Cheers

Alan

[nnickusa]

Trent is actually my neighbour. We live about 500m from the river/beach complex here in Brunswick Heads, so, yes, you could say there may be some minor influence from "oceanic" conditions...

[Tod Gilding]

Thanks Alan that's something that I will consider in future as I live about 300m from the ocean
all of my guitars soundboards rise and fall with RH but something that I have noticed is that my Falcate Braced guitar is unbelievably stable it doesn't move at all that I can notice with the eye and the action.

[ozziebluesman]

Hi Tod,

Yep I reckon the Falcate bracing would be super light, responsive and strong.

I made two guitars for my son. One is a dready with sitka spruce top and red spruce bracing. I also tucked the bridge plate, the two tone and finger braces on the top. I believe that it is common for the bridge to roll forward a little with this type of bracing design but I figured it might help the guitar to live in wet conditions. I also shellaced the inside of the box as a protection against moisture absorbing into the inside of the guitar fast. The other was an all blackwood 018 and I did the same bracing design and shellac process inside the box. Both guitars have been living on the island for twelve months. The blackwood guitars top has not moved but neck joint did severly and I had to reset the neck. Since he reset it has been stable. I used HHG inside the box and under the fingerboard and bridge as a choice of glue. So far, so good!

Cheers

Alan

[simso]

They did, however, talk him into having a poly finish laid over the top, thereby making it stronger. Not sure I buy that, but it's done and I'm not going to address that issue either.

Its amazing the BS that exists out there, rip off merchants/snake oil salesman and general all round shit people that are just ripping people of for a few bucks

Okay Ive had my bitch, now lets repair.

I see from the photos a few issues, you can choiose to addrw=ess them or leave them your choice.

First issue , the area in front of the bridge has bellied down, I would check my bracings and re-humidify to start with

Double check you bridge plate is still there and even more that its still bonded well and of sufficient size, may need replacing or modifying, dependant on his budget a cheaper path whilst I dislike the product, is this instrument may benefit from the use of a bridge doctor.

Remove the bridge via heat and a putty knife. Once removed the instrument may benefit from having the top steamed and flattened again

Before putting the bridge back on, see if the guitar has an arch in the top or its flat, sand the reverse profile into the base of the bridge, if theres not enough meat to keep a good action height then make a new bridge.

Make sure the area being glued down too is super clean, and then simply glue and clamp with titebond.

Ask as many questions as you want, we pretty well do this repair on a daily basis

Steve

It also looks like it has a crack that runs from the back all the way up on the lower side from the photo, fix it properly before anything else

The front edge of the rosette also looks creased, so maybe it needs some more bracing up the front to stiffen the pressure from the neck block

[nnickusa]

Thanks Steve,

I'll get the bridge off, take some beter pix and get back in touch. I appreciate the help..

Nick

[Eric Reid]

A few things I would do differently:

1--I like to heat the bridge, not the "putty knife". I mask the top of the guitar with a 1 cm layer of styrofoam covered with aluminum foil, with a cut-out for the bridge, and focus a 250 watt heat lamp on the bridge. Heating the knife will cause finish damage. If you're subtle, and the finish is thick, maybe you can buff it out. I mainly work on French polished guitars. No matter how subtle you are, you won't buff out the finish damage from a hot knife on a French polish finish.

2--Pay attention to run-out. Most tops have run-out. Many tops have a lot. If you insert the knife against the run-out, you'll get significant top damage. Look for a difference in color along the center seam. Sometimes this is obvious. Sometimes it's not. Try turning the guitar end for end with raking light to see if the color difference will swap sides. You want to run the knife in from the lighter side. I like to think of it like this: if I'm looking at a stack of stainless steel pipes angled at 15 degrees, from one end of the stack, they look silver (I'm looking at the sides of the pipes), from the other end, they look black (I'm looking down the bore of the pipes). If you can't see the difference, still, pay attention to the feel of the knife. You should be able to tell when you are parting a glue line, and when you are parting wood fibers.
Most tops are book-matched, so the knife will need to be inserted from opposite directions on either side of the center seam.

3--"Putty knife" A putty knife could probably be made to work. A cake decorator's spatula might be better. If you plan to go on doing this, I recommend making your own tool. If you're a smith, you don't need my advice. If you're more of a wood guy than a metals guy, try this: find a long, thin knife at a thrift store (jumble shop?). Regrind the blade so that it is sharp on both edges. Try not to over-heat the blade while you're grinding (the metal changes color as it gets too hot--pale yellow, brown, purple, blue)
Over-heating is not critical here. Put a slight radius on all the edges, and have a go at a few beaters.

[auscab]

Hi Nick ,
your getting plenty of good advice !
I was just thinking back to a thing I read on frets . com once, where it said one of the
reasons bridges let go is because the ball ends on the strings on an older guitar
sometimes wear their way through a bridge plate, they then don't last to long
pulling on the spruce and end up pulling only on the under side of the bridge.

Just another thing to look for while your in there with the mirror.

I had a friend come in and show me a 70s Martin , the
top was dipping in front of the bridge ,and up at the back and I think the bridge was still
stuck on ok . I checked the condition of the bridge plate and those ball ends were well
on their way to going through, they probably had 15% of the plate left with a rough guess.

[nnickusa]

Hey Rob,

You're not kidding, great advice every time I look for help. This is a forum full of bloody enablers....

I'd buy 'em all a coldie if they was here....

I'll sort this one out. My mate really only wants the bridge stuck back on, as he wants to sell it.....We'll see....I'l have a chat with him this weekend, if I get any time away from my now-dried out tops and backs.....Gonna be a glue-fest this coming weekend....

How was your pumice project? did the stuff I sent you do the trick?

[simso]

A quick clarification as someone may have interpreted what I said incorerectly

Quote "Remove the bridge via heat and a putty knife"

Response "A few things I would do differently: 1--I like to heat the bridge, not the "putty knife". "

That was the intent of my statement as well.

[auscab]

Hey Rob,
How was your pumice project? did the stuff I sent you do the trick?

Nice pumice Nick, I couldn't get over how fine it is compared to what I had sitting on my shelf . Ive been playing with grain filling big Oak tables , and/or silica they both seem to do the same thing, the time it saves is huge.

[Eric Reid]

A quick clarification as someone may have interpreted what I said incorerectly

Quote "Remove the bridge via heat and a putty knife"

Response "A few things I would do differently: 1--I like to heat the bridge, not the "putty knife". "

That was the intent of my statement as well.

My error.

[nnickusa]

Don't get nervous, Eric, I read both of your suggestions the same way. Where are you located, and what have you been doing? Have I missed an earlier post of yours that brought you to the forum?

If I have, I apologise....And a belated, if that's the case, welcome....

Cheers, and thanks for the input.
Nick