fractured very tall bridge

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Todd Stock
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Re: fractured very tall bridge

Post by Todd Stock »

Sometimes, these 'cascading series of miseries' sorts of jobs can be fun in the same way that a 0-7 hockey game can be interesting for fans of the losing team...

Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

Looks like and seems to melt like the white or yellow glues. Didn't know about the vinegar. Just drip it from the top? of the fb or try to drip in from all sides? I could drill a few small holes in the joint too.

Clay Schaeffer
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Re: fractured very tall bridge

Post by Clay Schaeffer »

The vinegar will soften the glue it comes in contact with. You can wet the joint, allow it to work some, dig out the soft glue, wet the joint again, repeat.
Another thing you could try is heating a thin bladed knife or palette knife and use that to soften the glue and dig it out. If you have an oscillating tool and a narrow blade you could plunge cut from the top and "saw" the glue out of the joint. No easy way that I can think of. Unfortunately what you ran into was not a bolt on neck, but rather a glued in neck clamped with bolts.
If the heel is thick enough to support an insert another approach might be to carefully saw off the neck and make a butt joined bolt on neck out of it. Tape the body around the heel to protect the finish. You are replacing the bridge and fingerboard any way, so the slight loss of neck length shouldn't be a problem.
These projects are learning experiences, which we as amateurs can afford to take on (I have been an amateur luthier for a little over 40 years now). Professionals know there is no money in it - they have learned through experience what to avoid. Todd offered good advice from a professional's perspective. Many things which are not apparent initially become so as the project progresses. But again we learn from these travails, and hopefully gain a lot of insight from them.

Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

Well its a challenge to me now. :shock:
I wonder if I should bag it and get the hot rod from stewmac and drill some holes and heat the joint. I will get my friend to pay for it. He is willing. I am trying the vinegar but there is also no space at all at the end of the tenon to the heel block. So, it is bottomed out. Could saw that out with my dremel multimax since one should really not let tenons bottom out.
Kind of interesting that every operation I perform on this gorgeous curly maple guitar shows another very very basic error even I didn't do with my very first guitar with a bolt on tenon neck.
Clay, Thanks for staying with me on this.
The photo shows the tenon to heel block with no space. Also the truss rod slot shimmed with thin card stock (don't know that technique) and the frozen hot rod.
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Clay Schaeffer
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Re: fractured very tall bridge

Post by Clay Schaeffer »

"I wonder if I should bag it and get the hot rod from stewmac "

If you are going to replace the truss rod you might want to use something other than a hot rod. Many people have reported bad experiences with them. What kind of heel does the neck have? It might be more practical to saw off the neck leaving the tenon in place and make a butt joined bolt on - it might make resetting the neck angle easier.

Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

I meant the heat stick from stewmac, the one that is basically a copper rod fitted to a soldering iron. Boy, I hate to cut the tenon off just cause of the destructiveness of that :oops: but could be the best thing to do.
When using the vinegar, how long to wait before the glue softens and if you don't get back to it the same day, does it harden again? Also, drip it in from the side of heel as well as the fretboard side? This is one of those situations that requires a lot of musing, standing back, rubbing the chin, waiting a couple days, start again; hoping a quick and easy idea comes to mind. I am glad my friend is not in a hurry.

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Barry Daniels
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Re: fractured very tall bridge

Post by Barry Daniels »

Drill a small hole at the end of the tenon for insertion of the steam needle, or, even better, the heat stick.
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Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

Wow, it would cost me around $150 to get that heat stick since I don't have the right soldering iron. Maybe go steam needle. Looks like I could build one of those.

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Peter Wilcox
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Re: fractured very tall bridge

Post by Peter Wilcox »

My own 2 cents says cut the neck off and reset it as the easiest fix. I did this to a classical years ago roughly following the instructions here:

http://www.frets.com/FretsPages/Luthier ... eset1.html

and it was straightforward and came out OK. There are also lots of youtube videos of similar processes.

He uses what he calls a "bone saw" - it's not, it's a cast saw, and you can use a Japanese pull saw just as well. Even though the kerf is about 0.020" instead of 0.010", that won't matter since you are going to replace/reset the bridge.
Maybe I can't fix it, but I can fix it so no one can fix it

Bill Raymond
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Re: fractured very tall bridge

Post by Bill Raymond »

A Japanese-style flush cutting saw (I bought one from Home Depot) might work well and prevent any scarring of surrounding finish caused by tooth set.

Clay Schaeffer
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Re: fractured very tall bridge

Post by Clay Schaeffer »

Cutting off the tenon will only work if you have enough heel thickness to add an insert for the bolt to screw into - so please keep that in mind if you decide to go that way.
If you do - Harbor freight sells a cheap oscillating saw (sale price $14 single speed, $20 variable speed) that combined with a "half moon" or straight plunge cutting blade can made short work of neck removal. The blades are very fine kerf and minimal "set" so work good for flush cutting. Again, tape the body to preserve the finish.
www.harborfreight.com/oscillating-multi-tool-62866.html

Narrower plunge blades could be used with the oscillating tool to cut the glue joint around the tenon, if that is your preferred method.

If the vinegar dries out the glue will harden again. I usually wait 15 to 30 minutes to give the vinegar time to soak in and work. I saturate pieces of paper towel and lay that on the area I want to soften up. The paper towel acts as a reservoir for the vinegar and helps saturate the glue. As I mentioned using a small drill bit you could drill small holes in the glue seam and pour vinegar into them to help it get deep in the joint.

Alan Carruth
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Re: fractured very tall bridge

Post by Alan Carruth »

Some years ago I was given some methyl cellulose to add to the vinegar to produce a gel. It keeps it from running all over the place, and also slows evaporation. I don't know where you'd get any. I believe that 'De-Glue Goo' is that sort of gel.

Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

The tenon is so nice and well fitted that I am going to try steam to get the neck off, ordered the needle from stewmac with hose. The hot poker thing from stewmac is "WOW" did I say "wow" very expensive :roll: , isn't it.

Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

I have the dremel ossilator saw, the multimax (that thing is amazingly useful), I have used the one from HF but it has lots and lots of vibration. It is fine for very occasional use.

Clay Schaeffer
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Re: fractured very tall bridge

Post by Clay Schaeffer »

The variable speed HF oscillating tool has much less vibration than the single speed model, but I'm sure there better tools. HF tools are uneven quality - some "batches" are better than others.
Fein makes a nice oscillating multitool and as many uses as I have found for the tool, I may eventually buy one. For now the cheap HF tools work O.K. and are 1/10th the cost.
I made a neck steamer out of an old electric tea kettle a length of aquarium tubing and a needle for inflating basket balls.

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Bryan Bear
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Re: fractured very tall bridge

Post by Bryan Bear »

HF power tools are inconsistent to say the least. You just can't assume that an issue with one applies to all of them. I had their stationary belt sander and hated it. It just had no power and bogged down on just about everything. A friend had one and he was giving it away because of the excessive vibrations. Mine ran super smooth but no power, his had plenty of power but vibrated itself off the table.
PMoMC

Take care of your feet and your feet will take care of you.

Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

Actually the dremel multimax has been great for me, smooth, powerful and its about $90.

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Barry Daniels
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Re: fractured very tall bridge

Post by Barry Daniels »

Yep, that Stew Mac stick is very pricey. I have one soldering iron that I can just pull out the tip and install a longer steel rod (1/8" dia.) And I could also turn a heat stick for my nice soldering iron on my Tail lathe. Next neck set that comes in will require some tool making.
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Mike Ryan
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Re: fractured very tall bridge

Post by Mike Ryan »

got the steam needle from stewmac and trying to adapt to a jiffy steamer now. That heated up rod definitely needs some hacking.

David King
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Re: fractured very tall bridge

Post by David King »

The Smith's CA debonder seems to do an ok job of melting titebond.

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