Official Luthiers Forum!

I just realized, I can't heat it up like a steel string Bridge because it has finish on it. Or can I?

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Pat

Good question Pat. I haven't done it so I'll not venture an 'opinion' and remain silent, but this will serve bounce it up.

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Joe Beaver
Maker of Sawdust

What finish? FP?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Not sure yet. A guy is coming over with a 70's Aria. He said it has glossy finish on it. Assuming lacquer?

And get this; he says someone glued it on backwards. Yep, saddle on the south side!

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Pat

Well, that's - different...
Asked for his money back ?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

At least for me, ruining the finish on a bridge would be the last thing I worried about when removing one. It has always looked kind of intimidating to me since it is on a finished guitar, and a bridge would be fairly simple to sand down and refinish if the heat damaged it. Any work around to the tried and true glue softening method risks damaging the top IMHO,
Mike

The only other way I've heard to safely remove a bridge is planing it off, and I'm pretty sure that is hard on the finish as well!

No telling what surprises lie ahead -- think I'd pass on that one.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Might be easier to cut a neck joint in the tail block and just finish what was started.

I've only done a few of these, and all of them were on less expensive polyester-finished instruments, including a donated Strunal that has had it's poor bridge on and off a half dozen times.

We have a couple boxes of old Aria and other brand classical bridges that came out of a shop in Baltimore, but both unfinished or finished regular and oversized classical bridges can be purchased from Allparts, Stewart MacDonald, WD Music, or Ebay for $5-$25 each. I would suggest taking measurements of the existing bridge and purchasing a slightly oversized bridge from Ebay or one of the other sources mentioned above. The advantage to an unfinished bridge is that it can be modified as necessary to shorten or reduce height without having to match the existing finish, and it's much less labor to French polish an unfinished rosewood bridge than to first strip, then polish. Prefinished bridges avoid the task of applying a finish, sanding, rubbing out, etc., so are a good option for cost-sensitive customers, assuming a new saddle does not have to be made up.

For better classical guitars, the boss nearly always reuses the bridge after carefully removing it with either an IR lamp or silicone heating bridge blanket and lots of heat shielding. A non-contact surface thermometer is very useful here to keep the surface of the bridge from getting much warmer than 150 degrees or so - over time, the heat will soak through to the glue line and allow separation. The finish on our 1970's vintage Aria bridges is polyurethane, and they can be heated to 150-160 degrees without showing finish damage, so you might try that first before resorting to a rout-off.

For French polished instruments, the finish over the joint between bridge and top is so thin that a palette knife usually slides right in, but if in doubt (or for poly finished instruments), it's important to carefully score the finish around the base of the bridge...we use a single edge razor blade with spine removed, a layer of scotch tape on the contact side to prevent scratching of the finish by the blade, and a rare earth magnet or two to control the blade.

I hope this helps answer your questions. If you decide to proceed with a rout-off, there are some techniques that are useful, and it is worth checking the archives here for more information on the process.

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A constellation only takes shape when one maps the whole.
- Beth Brower

Best way to get this bridge off would be to first wet the top thoroughly with naphtha. Then in a clear, well ventilated area, apply heat from the inside. I prefer to use a book of matches tossed in the soundhole (wear safety glasses and stand back), while others may prefer a pad of steel wool struck against a 9v battery. The bridge will usually come off before the flames make it all the way through ght the top.

Or as Ken suggested, know when to walk away. Sure it can be fixed, but even in the best of scenarios where everything went smoothly (not a bet I would likely make), it still wouldn't likely be worth the investment.

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Eschew obfuscation, espouse elucidation.

Well, ya gotta get the thing off right? So if heat damages the finish then you will just need to fix it.

You could always try the cold removal technique

https://www.youtube.com/watch?v=t5Q4iUB ... e=youtu.be

Yep do it like he did. The pecking upset my wife but she'll live.


Sent from my iPhone using Tapatalk

I removed one from the top of one of my finished guitars using the dull chisel method that I saw John Hall use in a demo. Worked like a champ! I had to sand the top down anyway to get better response from the guitar, so I had to re-fin anyway, but it came off extremely cleanly. Only took a few minutes of tapping, and the bridge popped right off, almost no fibers on the bridge.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

If the bridge was glued on with AR, PVA, or hide glue then working vinegar in the joint with a (stainless steel) palette knife (or similar) can help with the removal. reading the direction of any runout is important to avoid digging into the top.

Classical guitar= thin top
Aria = ply?
The bridge has been removed once already = thinner top
Your going to remove it again and all traces of what is most likely insoluble glue = even thinner top.
hmmm.



I have often thought of making a little instrument cemetery outside my shop.
Little white crosses with instrument names.
An impediment to decision making for many is, what to do with something that still looks like an instrument but is, sadly, gone.
Many might be soothed if I could hand them a certificate stating the official T.O.D., a shovel, a nod towards a plot.

The responses thus far make me realize why we get so many referrals from the classical guitar shop in Baltimore and the various instructional programs near DC and Baltimore - no one wants to do much of any work on the poor darlings!

Some older Arias are ply; some solid. Like Yamaha classicals, it depends on model.

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A constellation only takes shape when one maps the whole.
- Beth Brower

LOL! I like the idea of the guitar cemetery!