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Referral job
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=34578		 Page 1 of 2
Author:  Tai Fu [ Thu Dec 15, 2011 4:16 am ]
Post subject:  Referral job
Here is the referral I got, it's not a really bad repair either.

Here is a Taylor 414CE with Ovankol side (I thought it was koa because of the flame, didn't look closely). According to the luthier the owner tried to reglue it with CA glue. The luthier just thought he slap some more titebond to the loose bridge and clamp, but in reality the bridge really needs to come off...

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Here is the setup:

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It took a while... and I got concerned when the soundboard got a bit hot too so I continued without the shield. But eventually the glue let go.

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I don't know if it was the heating to remove the bridge, or conditions that caused the bridge to come loose in the first place, but the wings are slightly warped. I tried to correct it by soaking it in boiling water but it did not help. So I used an iron to flatten it as much as I can, then sanded the bottom flat.

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So finally I flattened the bottom and routed the ledge back in (Taylor bridge has a ledge that simplifies gluing), I heated some hide glue and clamped it back on:

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Will string it up tomorrow and see how it sounds...
Author:  jonsse [ Thu Dec 15, 2011 9:34 am ]
Post subject:  Re: Referral job
Well done Tai [:Y:]
Author:  Chris Pile [ Thu Dec 15, 2011 9:47 am ]
Post subject:  Re: Referral job
Looking good.
Next time you boil a bridge.... make tea. laughing6-hehe
Author:  Tai Fu [ Thu Dec 15, 2011 10:04 am ]
Post subject:  Re: Referral job
Chris Pile wrote:
Looking good.
Next time you boil a bridge.... make tea. laughing6-hehe


The water did sort of turn tea colored... but I somehow doubt Ebony juice is very healthy...
Author:  cphanna [ Thu Dec 15, 2011 6:57 pm ]
Post subject:  Re: Referral job
Looks to me like you did a good job. I would not have attempted such a repair, except on my own personal guitar. Let us know how it goes when it's strung up again.
Author:  Tai Fu [ Thu Dec 15, 2011 8:53 pm ]
Post subject:  Re: Referral job
cphanna wrote:
Looks to me like you did a good job. I would not have attempted such a repair, except on my own personal guitar. Let us know how it goes when it's strung up again.


When you're doing this for a living, you kinda don't have much of a choice except to do it on a customer's guitar. Plus when you're fixing a customer's guitar you gain valuable experience that you wouldn't get otherwise. There are risks, but as long as you're familiar with the step its not a bad risk to take.

Besides I am doing them a lot of favor because in Taiwan there's no one who is really qualified to fix an acoustic guitar.
Author:  jfmckenna [ Fri Dec 16, 2011 4:27 pm ]
Post subject:  Re: Referral job
Mmmmm Ebony soup. I've never heard of such a technique for getting bridge warp out. By the looks of your pics it almost appears that the bridge had glue applied only to the perimeter. You can see a defined glue line along the perimeter of the bridge but not in the middle. Do you suspect that's the case?
Author:  Tai Fu [ Fri Dec 16, 2011 8:40 pm ]
Post subject:  Re: Referral job
jfmckenna wrote:
Mmmmm Ebony soup. I've never heard of such a technique for getting bridge warp out. By the looks of your pics it almost appears that the bridge had glue applied only to the perimeter. You can see a defined glue line along the perimeter of the bridge but not in the middle. Do you suspect that's the case?


That's because Taylor like a few other manufacturer routes a microscopic lap into the perimeter of the bridge, so that they only have to cut a profile on the finish where the bridge is slightly smaller than the bridge itself, and the two pieces fit seamlessly without gap. However when I try to duplicate it I always end up with a small amount of gap in the corner of the bridge, possibly because Taylor uses precision CNC to duplicate very exact dimension whereas I have to approximate it with a router. I doubt I could even duplicate that even with a milling machine.
Author:  Tai Fu [ Sat Dec 17, 2011 7:31 am ]
Post subject:  Re: Referral job
An update:

There's a small gap in the corner and the luthier who referred me told me to do it over again, because that gap no matter how small is not acceptable, since that's what he was complaining about to begin with.

So I ended up taking the bridge off again and was wondering why that gap was there in the first place. I traced it down to the fact that since the bridge had warped, that part was already springing up and unless I make a new bridge (which is not something I wanted to do), all I could do is apply heat in that area and bend it down a little bit.

So this time I made a few dry runs before actually taking glue to the thing again. I made a few clamping blocks to put more pressure in that area and it looks like the gap has disappeared. So I tried again with glue and it seems to have worked, but there is still a .001" lip in the corner due to corner rounding... I just hope this is good enough because if not, I think I am going to commit Guitar-icide.
Author:  Jeff Highland [ Sat Dec 17, 2011 3:09 pm ]
Post subject:  Re: Referral job
Please don't be offended, But I think you have been extremely lucky not to seriously damage the guitar by the way you have approached this repair.
The foil masking which you used with a gap around the bridge like that could have lead to the finish blistering where exposed. A clothes iron really is not the right thing to use.
The warping of the bridge is to be expected when you heat one side of it, boiling is not the answer, and any bridge which has been soaked should not be leveled and glued in place in the time frame you have worked to.
You really do need to work to more realistic time frames and communicate that to the client
Author:  Tai Fu [ Sat Dec 17, 2011 8:34 pm ]
Post subject:  Re: Referral job
No, I am not offended at all, in fact I am mostly humbled.

Other than the guitar repair blanket (which along with the controller, is a costly investment), I just can't think of a better tool than an iron or heat lamps. The problem being I need to find those spring arm work lamp that doesn't use LED or florescent technology because that's all I've managed to find these days. In fact I've heard rumors that they wanted to outlaw incandescent light bulbs because they're an energy waster. The issue being since LED and florescent lights are so efficient, they produce next to no heat...

If I do use light bulbs to heat a bridge, what wattage do I need?

I kinda wish there is a school which teaches repair technique, even better if it's online. I know many luthier school mostly teaches how to build a guitar and other building techniques.

It's little wonder that I got the referral job because that luthier doesn't have the ability to heat a bridge off without damage.

Also, thank God for Taylor's bulletproof UV poly I guess...
Author:  Jeff Highland [ Sat Dec 17, 2011 9:42 pm ]
Post subject:  Re: Referral job
I have an LMI bridge heating blanket sitting in my workshop, I have not used it yet but it is there when I need it.
Rather than buy the controller (and we are on 240V here so there controller was not suitable) I use a 1200 watt dimmer switch for the bending and repair blankets.
Frank Ford's site www.frets.com is as good a source of repair information as you will get
Here is his bridge regluing tutorial
http://www.frets.com/FRETSPages/Luthier ... uebr1.html
Author:  tomlang [ Sun Dec 18, 2011 12:40 am ]
Post subject:  Re: Referral job
I agree with the use of your clothes-iron to loosen the bridge. Your insulation, however, was counter productive. I have found that several layers of corrugated cardboard-box material to act as a heat sink will protect the finish on the top. I think this trick came from Mr. Compiano, but not sure. Use at least 4 layers of the cardboard, cut out for the shape of the bridge, set your iron for linen and be patient. Hot glue will loosen in just a few minutes. Using a heating blanket is more involved, so I don't use mine any more.

Hope this helps,
Tom
Author:  Tai Fu [ Sun Dec 18, 2011 1:35 am ]
Post subject:  Re: Referral job
tomlang wrote:
I agree with the use of your clothes-iron to loosen the bridge. Your insulation, however, was counter productive. I have found that several layers of corrugated cardboard-box material to act as a heat sink will protect the finish on the top. I think this trick came from Mr. Compiano, but not sure. Use at least 4 layers of the cardboard, cut out for the shape of the bridge, set your iron for linen and be patient. Hot glue will loosen in just a few minutes. Using a heating blanket is more involved, so I don't use mine any more.

Hope this helps,
Tom


4 layers of cardboard box material would be thicker than the bridge itself, so I'd be heating the cardboard and not the bridge. I mean each layer of cardboard is close to 1/8" thick.
Author:  John Arnold [ Sun Dec 18, 2011 2:05 am ]
Post subject:  Re: Referral job
For a shield, I use a single layer of white finish corrugated cardboard. The window is 1/8" smaller than the bridge all the way around. I use a 250 watt heat lamp. Heat lamp bulbs have a very long life....I have used the same bulb for over 20 years.
To straighten the bridge wings, I use a small heat gun (the kind used for electronics). It gets really hot. Holding the bridge in my hand, I press the corner against the work bench, reheating as necessary. It only takes a minute or so.
Author:  Tai Fu [ Sun Dec 18, 2011 3:35 am ]
Post subject:  Re: Referral job
John Arnold wrote:
For a shield, I use a single layer of white finish corrugated cardboard. The window is 1/8" smaller than the bridge all the way around. I use a 250 watt heat lamp. Heat lamp bulbs have a very long life....I have used the same bulb for over 20 years.
To straighten the bridge wings, I use a small heat gun (the kind used for electronics). It gets really hot. Holding the bridge in my hand, I press the corner against the work bench, reheating as necessary. It only takes a minute or so.


So kinda like bending wood right?

What do you mean the kind of heat gun used for electronics... I've seen those butane powered thing that are used for shrinking tubings, is that what you mean? I was thinking a hair dryer may be safer...
Author:  truckjohn [ Sun Dec 18, 2011 8:53 am ]
Post subject:  Re: Referral job
You can buy very small heating irons for veneer use - Check out the hobby Model Airplane catalogues as well.... Look for the irons and heat guns they use to shrink the plastic wing coverings... They are frequently called "Sealing irons"

Here's an example, but the same place sells like 5 different ones:
http://www3.towerhobbies.com/cgi-bin/wt ... XHZ17&P=ML

Heat guns are like hair dryers - except they get MUCH hotter...Hot enough to burn you seriously....
Here's an example from the same place...
http://www3.towerhobbies.com/cgi-bin/wt ... LXHZ16&P=M

Once again - check out the Model Airplane folks or veneering supply catalogs for these products...

Thanks
Author:  WendyW [ Sun Dec 18, 2011 9:12 am ]
Post subject:  Re: Referral job
You said that you sanded the bottom of the bridge flat. Does the Taylor not have any dome to the top? Wouldn't you have to sand the bottom of the bridge to match the top doming? Or did I miss something?
Author:  Tai Fu [ Sun Dec 18, 2011 10:11 am ]
Post subject:  Re: Referral job
callyrox wrote:
You said that you sanded the bottom of the bridge flat. Does the Taylor not have any dome to the top? Wouldn't you have to sand the bottom of the bridge to match the top doming? Or did I miss something?


The Taylor does have a dome, but it's fairly flat. I've noticed as I took the bridge off that it had absolutely no relief sanded into the bottom to match the top dome, I am not sure if its due to the bridge warping out of shape or that it had no relief in the first place. I had to remove quite a bit of wood before I was able to match the bridge to the body, and nothing I did otherwise corrected it.

I even checked Factory Fridays to confirm how they made their bridge, but I couldn't see if they had any bottom radius carved into the bridge.
Author:  WendyW [ Sun Dec 18, 2011 10:48 am ]
Post subject:  Re: Referral job
I would just lay a piece of sandpaper on the guitar in the bridge location and rub the bottom of the bridge back and forth until the entire bottom of the bridge is covered in sanding scratches. Then it should match the soundboard shape perfectly.
The problem with removing a lot of wood from the bridge is that you are changing the thickness of the bridge, which was originally matched to the neck angle and action of the guitar.
Author:  WendyW [ Sun Dec 18, 2011 10:58 am ]
Post subject:  Re: Referral job
Were the wings of the bridge warped like that before you removed it? In the third picture, when it is still on the guitar, the wings don't look warped. Maybe it just doesn't show in the picture. I would talk to Taylor and see what they say about the warped wings. Maybe you could get a new bridge from them if they warped while on the guitar.
Author:  Tai Fu [ Sun Dec 18, 2011 11:10 am ]
Post subject:  Re: Referral job
callyrox wrote:
Were the wings of the bridge warped like that before you removed it? In the third picture, when it is still on the guitar, the wings don't look warped. Maybe it just doesn't show in the picture. I would talk to Taylor and see what they say about the warped wings. Maybe you could get a new bridge from them if they warped while on the guitar.


I think it may have warped due to being left in a hot car, but it was warped from the beginning.

In any case if the guitar was still under warranty, having a third party work on it pretty much voids all warranty.
Author:  truckjohn [ Sun Dec 18, 2011 5:30 pm ]
Post subject:  Re: Referral job
While that's theoretically true and all... they may not have Taylor factory authorized service in Taiwan... If that's the case - it's a long and expensive trip back to the USA...

Thanks
Author:  WendyW [ Mon Dec 19, 2011 10:34 am ]
Post subject:  Re: Referral job
Actually I wasn't suggesting sending the guitar back for warranty work. I just thought that Taylor might find it interesting that the wings of the bridge warped and that they might be willing to provide a new bridge regardless of warranty, especially considering the location of the guitar. Is it common for bridge wings to warp? I've never seen that before. I would think a lot worse would happen to a guitar left in a hot car, before the bridge wings would warp. I'm just wondering if it is due to some defective character of that piece of wood.
Author:  Tai Fu [ Mon Dec 19, 2011 10:38 am ]
Post subject:  Re: Referral job
callyrox wrote:
Actually I wasn't suggesting sending the guitar back for warranty work. I just thought that Taylor might find it interesting that the wings of the bridge warped and that they might be willing to provide a new bridge regardless of warranty, especially considering the location of the guitar. Is it common for bridge wings to warp? I've never seen that before. I would think a lot worse would happen to a guitar left in a hot car, before the bridge wings would warp. I'm just wondering if it is due to some defective character of that piece of wood.


It might be... because if the warping was caused by an external force like heat, then it should return to normal once you boil the bridge in water for a few minutes.

Bridge wing seem more affected by conditions though because its so thin
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