Official Luthiers Forum!

Hello everybody. It has been forever since I've been on here, I've just been too busy.
I'm am so mad right now about what just happened in my shop. I have a custom order guitar that I am working on that has been going on forever. I missed the date I wanted to deliver it by very badly. But anyways I was right at the end string the thing up. Have nut and saddle made and everything. And just as soon as I start tuning her up good and tight I hear something cracking. It's lightly, but I can definitely tell something is giving. So first I start looking around the bottom edge of the bridge to make sure it isn't coming away from the soundboard. And of course no problem there, it's nice and tight. But then I notice what happened. Right at the end of the treble side of the saddle slot the bridge has cracked!!! I have no idea why. The saddle is at about 3/16" tall in the center, a little less on the ends. And it fits nice and tight. Certainly not too tight. Maybe a tad to loose, but it's still kinda hard to take it out without anything to grab it. You can take it out with just your fingers, but with a couple seconds of working on it. So I am thinking it had to be a defect in the bridge, in the wood. What do you people think? Cause if there is anything in the design that could have cause this I want to know? I have also never had a bridge do this. I'm just pretty sure it has to be defective wood, but I want to be sure.
Also I would like any tips and info on how the heck I'm gonna get the bridge off without damaging the guitar finish any? I have taken a bridge off before, but only one that was already coming unglued. I have never taken one off that was glued down tight all around so I really need any tips help and info I can get. I'm panning on ordering the bridge blanket heater from LMI. I really want this replacement job to be good. Oh and by the way, I also tried gluing the crack shut, just to see. Because it really makes me sick to have to replace a perfect bridge, but anyway, it cracked again when I started putting pressure on it. I think it is cracking along the bottom of the saddle slot too. Like that whole front piece of the saddle would break off if you kept putting more pressure on it. Not sure, but thats kind of what it seems like. Any info would be so greatly appreciated.
Thanks!!

The pics are pretty bad. For some reason my camera will not take a focused closeup shot. Just thought I'd post a few on anyway.

I've seen bridges crack for no reason. I suspect an.........."almost" crack was hiding in the bridge just waiting for a little pressure. Removing it shouldn't be a problem. I've replaced bridges on a bunch of old guitars as well as a couple new builds. What kind of glue did you use? I've got a little heating blanket for removing bridges but I removed a bunch of them with a clothes iron before I got it. I keep damp cloths around the bridge to keep the top from getting too hot. Take your time, and it shouldn't be a problem. Let the heat loosen the glue and don't force it.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Hi Colby.

The first thing I see that's wrong is the amount of wood in front of the saddle. You don't have enough of it. It looks like there is only 3/32'' at the trebble side. You need more, at least 3/16'', if not 1/4''.

Also, how deep is the saddle slot? It may not be deep enough.

And lastly, 3/16'' is pretty high for a saddle. It puts a LOT of pressure on that little 3/32'' of wood in front of it. Specially if the saddle slot is not very deep.

As for taking off the bridge, I've never manage to do that without any trace. Always had to repair the finish around it. So I'll let others help you with that.

Good luck with that!

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

It's impossible to tell with certainty but it looks like it could be a combination of factors. The saddle is on the tall side and the break angle looks on the steep side. That combines to give you a lot of torque. The saddle slot extends almost to the bridge wings which cuts down on the strength there. Any of those factors alone probably wouldn't be a problem but it does add up. Or it could just be the wood.

As for removing the bridge, I would rout off as much as you can. Protect the top with a layer of poster board or some of that thin plastic sign board. Use double sided tape to attach a couple of runners to the base of your router making a channel somewhat wider than the bridge. Using a straight bit, rout off about 1/8" of bridge per pass till you've gone as low as you feel is safe (it's possible to rout it completely off but it takes patience and a steady hand). When you get it thin, it takes less heat for a shorter time to release the glue so you have much less risk of damaging the finish or separating the center seam.

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http://www.chassonguitars.com

Yep, that's a fairly common crack. Like others have said a bit more meat in front of the slot will help a lot, along with a deep enough slot and a saddle that is not overly high. This also shows why a perfectly quartersawn bridge blank is not necessarily ideal, an off quarter blank may resist that type of cracking more effectively. I would make the new bridge with a bit more wood on the front edge and call it good.

I almost always remove bridges cold with a thin palette knife, the most important thing is to watch the runout of the top and go slowly. In your case though, with a fresh possibly not fully hard finish and the necessity for no visual mess ups, the routing method is maybe a good idea. If you heat it, make sure you don't heat it enough to compromise the glue joints at the centerseam or bridge plate, that's why i usually go cold, it is hard to heat the massive ebony bridge enough to release the glue without also heating the stuff directly under the bridge, and there is always the danger of overheating the finish and going insane.

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Jordan Aceto
Ithaca, NY

That's a great idea Ken!

Colby, I don't have the experience to give advise so take this with a grain of salt. When I first looked at the bridge, the first thing I noted was there was very little material in front of the saddle on the treble end where it cracked. Since your saddle location is set, if you add thickness there on the replacement bridge, the bridge will extend further forward so you will have to scrape off more finish before gluing.

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Formerly known as Adaboy.......

Sometimes cracks can be lurking in the blanks before we do anything to them. Had a problem like this myself on a newly finished guitar.Suspected it may have been in the original blank. Since then I always wash the blanks before use with some fast evaporating liquid like acetone or alcohal ,it flashes off fast but leaves a telltale mark if there is a crack. Have only found 2 cracks since and one I was able to work around. Think it saves heart break down the line.

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A person who has never made a mistake has never made anything!!!

Thanks for the replies guys!!! It all really helps a lot.
I have also been worried that heating the bridge real good might heat some of the things under it and I sure don't want that. I think I may try the routing off method somehow. I am very nervous about it, but it does seem like it would cause less damage to the finish. I also notice that it looks like there could be more meat in front off the saddle. I guess I will make the new bridge a tad wider. I think it's at about 1/8" right now in front of the saddle. 3/16" would be better.
You guys think I should try routing the bridge down to like 1/8"-1/4"? Do you think I could heat it with an old clothes iron. I hate to spend the money on a little heat blanket right now if I can avoid it. Any more info always appreciated. I'll try and keep you guys posed on what happens here.......

Cover everything but the bridge with a couple layers of paper towels for insulation. Then a layer of aluminum foil with a bridge shaped hole cut in it. Use a quartz work light about 6" from the propped up vertical top. Give it 5 minutes and it will lever right off with no damage to surrounding areas. I've done this three times now and had good results everytime. Good Luck! Mikey

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The Biggest Little City, Nevada
www.hammondguitars.com
I love building guitars!

Colby, I have pulled the bridge on a few old beaters and replaced them to fix intonation, I'm still working on getting them off with NO finish damage. Getting closer. The problem with the iron is that it overhangs the bridge and heat gets to the finish around it. I've had best luck with the heat lamp, I use an old home movie light that puts off plenty of heat. To keep the surrounding areas cool I've found that a couple of layers of corrugated cardboard with holes cut for the bridge and faced with tinfoil does a pretty good job. I haven't tried routing down the bridge and I can't decide whether bringing it down to about 1/8" so that less heat would be required would be a big help or just complicate things rigging up the routing jig. Seems to kind of fall in the 6 of one, half dozen of the other area, guess I'll have to try it at some point and see.

Good luck,
Joe

Mikey, what watt of lamp do you use? Also any other info on the lamp would be helpful? I don't have a lamp like this but I might be needing to get one...anything to get this bridge off safely!
Also do you think still rout the bridge down with this method, or fine to leave it normal?

Sorry to see this happen

Several posters suggested your bridge is perhaps poorly designed, and I can't comment about that since I don't know much about ss bridges, however I feel that it would not have happened if the wood was sound and solid. You can go ahead and put more meat on your next one, but don't blame this crack on yourself.

As for removing it, using the heat gives me the creeps too, so I would just try to chisel as much as possible off first. Protect the top well, sharpen the chisels to perfection and go slow. Don't expect to finish it in 15 minutes, better assign a whole day for the job and maybe it can be cleaned off perfectly by mechanical means. Of course if you have a fancy routing setup, try that...

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Build log

If you are going to the trouble of routing it, rout it right down to the spruce, or as close as you feel you can comfortably get. The little skin of ebony left will be fairly easy to skim off. Leaving 1/4" doesn't really give you much of any advantage.



A clothes iron is going to heat up everything around the bridge an unacceptable amount. I use variously sized chunks of steel, heated up on a hot plate sometimes, anything smaller than the bridge outline and massive enough to hold some heat will help, careful not to drop them on the top(or your sandaled feet)!

It would be really nice to be able to do this on a few cheapies before practicing on your beautiful shiny new guitar, but it sounds like you are unfortunately feeling a little bit of a time crunch also, rough break.

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Jordan Aceto
Ithaca, NY

Routing is not that big of a deal. Just protect the top, make sure the rails ,the bit, and then height adjustment are secure. Think it through, and go slow. Routing is way safer than using a chisel in my opinion and I've done both. And I agree with Jordan...take it down very thin.

It's certainly possible to do a flawless repair with heat and a full thickness bridge but it's difficult on a new guitar.

As for heating with a lamp, a 200 watt flood light works fine for me.

When heating, I like to overlap the cardboard insulation about 1/16" over the bridge around the perimeter to protect the finish. And make sure the glue has really released. It only takes a few fibers stuck to the bridge to really blow it.

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http://www.chassonguitars.com

Colby, why don't you see if you can't work a little glue in there and close the crack before you go to all that trouble of replacing the whole thing.
I would tape off around the bridge and get or make some kind of clamp that will grab the front and rear of the bridge. Even a "little" flooded CA might do the trick. If not then replace the bridge.

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Tickle your guitar daily, and it'll tickle you back.

Colby:
I just use one of the 500 watt halogen work lites that Home Depot sells. It works because the bridge is dark colored and soaks up the heat quickly. I have never bothered to cut off part of the bridge first, thinner would probably make it work even better. Most of the glues give up the ghost at around 150 degrees and the bridge will lever off easily and cleanly using a VERY thin blade of some sort .... Mikey

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The Biggest Little City, Nevada
www.hammondguitars.com
I love building guitars!

Hey Guys! I really appreciate all the help ya'll gave me on getting the bridge off. I finally successfully got it off. I really wanted to take it off with heat so I could use it as a template but on this one I chickened and decided to try routing it off. It sounded just a tiny bit safer. The thought of just seeing my finish damaged by heat freaked me out. It takes me forever to repair a finish.
Anyways I have another question I just wanted to run by ya'll to see if ya'll had any good ideas on the best way to go about this. I have replaced one or two bridges in my time, but they were always damaged or coming off already so I had no problem using just a little heat and getting them off. Then I would use the old bridge as a template for the bridge pin holes and everything. But since I don't have my old bridge I'm wondering what the best way to get the bridge pin holes and saddle slotted and all just right? I have the template for the outline that I use for all my bridges. What about maybe (1) cutting the bridge to outline. (2) Setting it in place on the guitar and measuring for saddle slot. (3) Somehow marking the holes from inside the guitar while the saddle is in place. (4) drilling the holes where marked....from the bottom side..? Then just cake from there if that all turned out perfect. Also I'll be adding and extra 1/16" in front of the saddle slot incase any of you remembered that. Anyways, if there is a better way to go about this, or any helpful tips, they would be much appreciated. Thanks.

Great looking take off job!!!

About marking the holes in the new bridge. What I have done and it worked pretty well, is cut out the new bridge outline getting it just right. put masking take on the bottom of the new bridge trimming it to conform with the shape, aline the bridge right where it needs to be and tape it down with masking tape. Then take a twist drill bit that just fits in the pin holes in the sound board and going up from the bottom (through the sound hole by hand) turn it back and forth in the pin holes. It will mark them pretty well on the masking tape.

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Joe Beaver
Maker of Sawdust

Just one thought on your old bridge... you cut nice slots for each string to rest in but they may be a little long. When they are that long they cause the break angle to become much greater. The same as if you put the pins that much closer to the saddle. That would increase the torque on the saddle contributing to the problem.

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Joe Beaver
Maker of Sawdust

Thanks for the tape tip man!! I knew there was some idea out there that would help make things a little smoother.
Also thanks for the tip on the break angle. I sure don't want to do anything to cause any problems on the new one. I had been thinking a break angle like that was good. Where the bridge wood didn't take any pressure off the string. I thought more pressure on the saddle would drive the top better? But also I was thinking the pressure was mostly downward, maybe it is more forward? So what is the best break angle to have? Anybody got a picture of a bridge/saddle setup with the perfect break angle?

Alain noted that the amount of material in front of the saddle was insufficient and is the possible root of your issue...perhaps making the replacement bridge with more material on the front side is in order? this means more mass, but you really can't just use the same exact shape and move it forward as the top is already finished

Yeah I just finished making the new bridge, haven't glued it on yet though. I did put more material in front of the saddle. I gave it a good 3/16" in front of the saddle this time. Also gave 1/8" clearance on each end of the saddle slot where the wings are carved down. Anymore info on a perfect break angle anybody?