Lifting Bridges - Updated

[Mr_LV19E]

Usually, that's all it should be. The trick is to get the bridge off cleanly, and if the problem is glue joint failure, then they should come off pretty cleanly. If the top has gotten damaged, that would indicate (to me) that the glue joint was decent, and there may have been another problem, or that there was a problem getting the bridge off.  

Wouldn't they just heat the bridge to soften the glue and then just peel it up with a thin putty knife?

I can stick a piece of printer paper under the bridge on my F-III in a few places, it's been like that since I got it and hasn't gotten any worse so I just figured it was no big deal. Maybe I was wrong.

[unclrob]

Yes you can heat it of.I've been using the old style method of  popping the bridge off forever and never had a problem.

Most companies leave about a 32" area of the bridge bottom clear of glue.I have seen bridge's that just have a swirl of glue and some that cover the whole bottom with glue.I've seen guitars  that had the bridge mounted to the finish that just had some scratche's into the finish.

[Mr_LV19E]

Yes you can heat it of.I've been using the old style method of  popping the bridge off forever and never had a problem.

Most companies leave about a 32" area of the bridge bottom clear of glue.I have seen bridge's that just have a swirl of glue and some that cover the whole bottom with glue.I've seen guitars  that had the bridge mounted to the finish that just had some scratche's into the finish.

So does that mean I shouldn't worry about my bridge?  I could send you a couple pics.

[unclrob]

Unless its lifting I wouldn't worry about it.Larrivee leaves about a 32' not glued.That little bit sits over the finished top.If it does lift get to your favorite tech/luthier and have it popped and reglued.

One thing I need to add,as a tech I have to know how everyone builds there stuff so I know how to fix it.Also I no longer do neck sets mostly because everyone thinks its so easy because they saw how its done on the internet and it looks easy.

[mlejeune67]

Mine was not that bad but I could get a piece paper about 1/8" under the bridge all the way across the back.  It didn't seem to me that this was there when I bought the guitar (I didn't really check though) and also the guitar is brand new and under warranty, so I thought I would at least get it checked out.  My dealer seemed to think that this was an issue and should be resolved now rather than later.  This sort of thing also would have kept eating away at me so I was glad to get it checked by the dealer and glad it's being resolved now.  Would it have stayed the way it is?  Hard to say. 

I checked my other two acoustics and one had absolutely no lifting at all and the other had slight lifting on the wing of the bridge but this guitar is about thirteen years old and has not always been babied so I'm not necessarily surprised or shocked at that.

Here's some coffee and donuts for all those chiming in on this one;   

[SMan]

It would not alarm me if I could slip a piece of paper slightly under the corner of a bridge.  (Keeping in mind that many acoustic guitar tops have a radius and are not flat .)  Lifting and being able to slip a piece of paper barely under an edge may be two different issues.

[kap55]

Usually, that's all it should be. The trick is to get the bridge off cleanly, and if the problem is glue joint failure, then they should come off pretty cleanly. If the top has gotten damaged, that would indicate (to me) that the glue joint was decent, and there may have been another problem, or that there was a problem getting the bridge off. 

What I was told by the fellow that repaired mine was that, during manufacture, once the surface of the guitar is finished a router is used to "rough up" the area where the bridge will be attached.  On my guitar this was uneven/irregular which is why he had to use a piece of maple to backfill prior to gluing the new bridge on. 

[Mr_LV19E]

What I was told by the fellow that repaired mine was that, during manufacture, once the surface of the guitar is finished a router is used to "rough up" the area where the bridge will be attached.  On my guitar this was uneven/irregular which is why he had to use a piece of maple to backfill prior to gluing the new bridge on. 

If they had to backfill why wouldn't they use Spruce, thats what the top is made of?

[kap55]

If they had to backfill why wouldn't they use Spruce, thats what the top is made of?

I'm not sure - I never thought to ask.  At the time I just figured the piece would be very thin and since maple is harder that it may have been more stable or easier to work with, but that's only my theory.

[unclrob]

If I'm not mistakenand I could be very wrong when I've removed bridge's from larrivee's the area were the bridge is being glue is taped off before the finish is apllied then after the finish is sprayed on then the bridge is glued into place.I don't believe that they route off the finish.

[jeremy3220]

If I'm not mistakenand I could be very wrong when I've removed bridge's from larrivee's the area were the bridge is being glue is taped off before the finish is apllied then after the finish is sprayed on then the bridge is glued into place.I don't believe that they route off the finish.

They do or did at least. It's quicker to route it off.

http://www.youtube.com/watch?v=wcJVh-kOXhg

[unclrob]

I rather not see them route off the finish to many chance's of damaging the guitar.I have seen some companies that will install the bridge then tape it off then spray on the finish.

[mlejeune67]

The video certainly tells a lot of the story.  Thanks!  Too bad it doesn't show the bridge going on.  From the video it would seem then that a critical part of this is getting all the finish off.  Perhaps it's harder to get it all off around the edges and the glue won't stick well to any leftover finish?

I've started to watch those videos but didn't make it all the way through.  Fascinating stuff though.

[jeremy3220]

The video certainly tells a lot of the story.  Thanks!  Too bad it doesn't show the bridge going on.  From the video it would seem then that a critical part of this is getting all the finish off.  Perhaps it's harder to get it all off around the edges and the glue won't stick well to any leftover finish?

That's true but decreasing the the wood to wood surface a tiny amount won't matter. It'd be the same as decreasing the footprint of the bridge an insignificant amount. Now if the left over finish(which is a raised surface comparatively) keeps the bridge elevated then that could cause a problem.

I rather not see them route off the finish to many chance's of damaging the guitar.I have seen some companies that will install the bridge then tape it off then spray on the finish.

Yeah but that's much more difficult or at least time consuming. For anyone who hasn't done this... It requires a patch of tape cut very precisely. Then you basically have to locate the bridge position twice which is kinda like in archery hitting the bullseye then splitting the first arrow with the second shot(ok, not quite that difficult but you get the idea). After the finish is applied then you have to precisely cut out the tape with a razor without cutting into the wood.

[unclrob]

Temp plated and a CAC might work but still..I saw a program which showed how Taylor use's a lazar cutter to cut the tops to shape I wonder if the technology has gotten to a point that a lazar could be use to remove the finish in the bridge area but having refinish a lot of guitars the finish gets deep into the wood.

[jeremy3220]

Temp plated and a CAC might work but still..I saw a program which showed how Taylor use's a lazar cutter to cut the tops to shape I wonder if the technology has gotten to a point that a lazar could be use to remove the finish in the bridge area but having refinish a lot of guitars the finish gets deep into the wood.

Actually, that sounds like a good idea. Maybe a template(like taping it off) to act as a backstop if the laser couldn't differentiate between finish and wood.

[sgarnett]

I have a 94 OM-10 with a lifted bridge. Last summer, I moved it to a closet that was on the opposite side of the bathroom wall - in other words, more humid than I realized. The weather here gets very humid in the summer anyway, though we use AC and a dehumidifier to keep it under control.

It isn't lifted very far. I only spotted it because I was holding it up to a light to admire the 3D effect of that incredible silking. I had just finished a very enjoyable practice session, and the tone was not suffering at all. However, a sheet of paper will slide pretty far under the center section of the bridge. It's currently sitting with loosened strings, waiting for better shipping weather.

[mlejeune67]

Had a bit of spare time this AM and thought I would try posting some pics to see if I could get it to work now that I have enough posts.  These are of the bridge of my L-03R prior to bringing it back to the dealer.

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[unclrob]

That looks like about the right amount of depth that would be were the bridge sits over the finish area under the bridge.I know this may be a dumb question but can you see it lifting or is it just that you can slide a piece of paper under it?This is not meant to offend just trying to understand better.Can you take a pix of the back of the bridge were it sits on the body.I'm just trying to get a better grip on whats going on.

[Mr_LV19E]

Here's some pic's of mine.  I haven't been real worried about it, just figured I'd send the photos to Jim once he's feeling better and let him decide what if anything should be done.