Official Luthiers Forum! :: View topic - Bridge gluing with no soundhole

with a pinless bridge. In that case, how would you go about gluing the bridge on?

Thanks, I think that really might be my only option. Repairability isn't a concern for me. This is just going to be an experimental guitar that in all likelihood will end up sounding awful!
Doesn't Trevor Gore glue the bridge early on so he can get the holes lined up with the braces? Can anyone with the book tell me how he goes about finishing with it in place? Or have I got that wrong?

I recall reading this from Frank Ford:

"Because it sets as it gels on cooling, hide glue can be used for “rubbed” joints where maximum strength is not required. Patches or “cleats” used to reinforce repaired cracks may be held in place by hand, pressing hard and sliding to squeeze out excess glue. When the glue cools, the cleat will be held in place by the gelled glue. Hide glue shrinks as it dries, and the cleat will be drawn tighter and will have sufficient strength in most cases."

In the article I read regarding rubbed joint on a classical bridge, the author said that this was actually the strongest bridge joint.

Doesn't match my experience.

kencierp wrote:

Doesn't match my experience.

It takes very little downward pressure to squeeze the glue out by rubbing. Warm everything up, and use plenty of glue so there's a good pool around the bridge while you rub. After a couple seconds you'll feel a bit of roughness as the surfaces make contact, and then you only have a small amount of movement left before it sticks in place and can't be moved without a full do-over. So start with larger movements and progress to small as it gets close. The whole thing is over in about 3 seconds.

As for strength, I'll have to run a test sometime, but I doubt it's much weaker (if any) than a clamped joint. The bridge on my redwood harp guitar has maybe 10 square inches of glue area, with lots of pointy bits for it to start peeling at, and has been fine for 2 years with 300lbs tension pulling on it and humidity ranging below 20% to above 70% throughout the year. And when we're talking softwood soundboards, the wood will peel long before full strength hide glue, so even a weaker joint would likely be more than enough anyway.

DennisK wrote:

kencierp wrote:

Doesn't a pool of glue around the bridge mess with the finish or is it a lot easier to clean up than other glues? I've never used hide glue.

Sent from my GT-I9300 using Tapatalk

I glued the bridge on a prototype with epoxy and no clamps. Worked great. Not very repair friendly though..

You could also do an access port in the heel.

Haven"t tried it myself, but locating pins and a go-bar deck comes to mind.

Brent

So there is no side port either? Nothing to get your hand in with? I would suggest using jacks on the inside if you can, if you can't then the vacuum clamp is the best answer though a high cost procedure for something you may only ever do once. It's not unheard of to use CA and glue the bridge right to the finish.

Author:	PeterF [ Sat Dec 05, 2015 2:01 pm ]
Post subject:	Bridge gluing with no soundhole
I'm in the planning stages for my next guitar and I'm trying to think around problems before I start building. I want to try not having a soundhole in the top along with a pinless bridge. In that case, how would you go about gluing the bridge on? Would the body cope with gently cam clamping it on from outside with no supports inside? Alternatively I suppose I could glue the bridge on before the back, but then it would get in the way of the finish.

Author:	kencierp [ Sat Dec 05, 2015 2:05 pm ]
Post subject:	Re: Bridge gluing with no soundhole
Quote: with a pinless bridge. In that case, how would you go about gluing the bridge on? I use a vacuum clamp

Author:	Hesh [ Sat Dec 05, 2015 2:10 pm ]
Post subject:	Re: Bridge gluing with no soundhole
Vacuum clamping is really the only choice. Conventional clamps need to be supported and the body structure would not be able to take the clamping force for gluing on a bridge. You can install jacks on the inside but you can't get to the inside now can ya.... There is a potential issue here in time too with serviceability. Most shops long after you and I are worm food and someone else needs to reglue that pinless bridge don't have proper vacuum clamping stuff. Just something to keep in mind. Even clamping with the back off is problematic in so much as imagine what the clamps will look like...

Author:	ernie [ Sat Dec 05, 2015 2:14 pm ]
Post subject:	Re: Bridge gluing with no soundhole
I/ve clamped ukes with no soundhole, using cam wood clamps and a padded wood caul on the back . I used 315 g HHG. I/ve seen other luthiers whose s. hole is in the upper left or rt bout. Vacuum clamping is good . But there must be other low tech alternatives ??

Author:	PeterF [ Sat Dec 05, 2015 2:25 pm ]
Post subject:	Re: Bridge gluing with no soundhole
Thanks, I think that really might be my only option. Repairability isn't a concern for me. This is just going to be an experimental guitar that in all likelihood will end up sounding awful! Doesn't Trevor Gore glue the bridge early on so he can get the holes lined up with the braces? Can anyone with the book tell me how he goes about finishing with it in place? Or have I got that wrong?

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Author:	johnparchem [ Sat Dec 05, 2015 2:41 pm ]
Post subject:	Re: Bridge gluing with no soundhole
PeterF wrote: Thanks, I think that really might be my only option. Repairability isn't a concern for me. This is just going to be an experimental guitar that in all likelihood will end up sounding awful! Doesn't Trevor Gore glue the bridge early on so he can get the holes lined up with the braces? Can anyone with the book tell me how he goes about finishing with it in place? Or have I got that wrong? In the book he just drills the 4 of the bridge pin holes. The bridge goes on after finishing. Classical guitar builders often glue on the bridge first and french polish around it. I find it a pain my self but I have build one guitar that way. I think they do it so they can string it up in the white.

Author:	wbergman [ Sat Dec 05, 2015 4:10 pm ]
Post subject:	Re: Bridge gluing with no soundhole
I have never done a rubbed hide glue bridge, but my understanding of an article I read is that it does not require clamping.

Author:	DennisK [ Sat Dec 05, 2015 5:48 pm ]
Post subject:	Re: Bridge gluing with no soundhole
There was a thread on Ukulele Underground recently where we discussed options for this http://forum.ukuleleunderground.com/showthread.php?116693-The-Thin-Ukulele-Interim-Results Hide glue rub joint will work. Another method I've done before is to install the top binding before closing the box, French polish the top, glue the bridge, then close the box and polish the rest. I wouldn't put much pressure on the soundboard without support underneath. It may work if the bridge wings are flexible enough to bend upward when the soundboard squishes down, but even then it would build stress into the joint.

Author:	kencierp [ Sat Dec 05, 2015 6:07 pm ]
Post subject:	Re: Bridge gluing with no soundhole
I recall reading this from Frank Ford: "Because it sets as it gels on cooling, hide glue can be used for “rubbed” joints where maximum strength is not required. Patches or “cleats” used to reinforce repaired cracks may be held in place by hand, pressing hard and sliding to squeeze out excess glue. When the glue cools, the cleat will be held in place by the gelled glue. Hide glue shrinks as it dries, and the cleat will be drawn tighter and will have sufficient strength in most cases."

Author:	wbergman [ Sat Dec 05, 2015 7:50 pm ]
Post subject:	Re: Bridge gluing with no soundhole
In the article I read regarding rubbed joint on a classical bridge, the author said that this was actually the strongest bridge joint.

Author:	DennisK [ Sat Dec 05, 2015 8:16 pm ]
Post subject:	Re: Bridge gluing with no soundhole
kencierp wrote: I recall reading this from Frank Ford: "Because it sets as it gels on cooling, hide glue can be used for “rubbed” joints where maximum strength is not required. Patches or “cleats” used to reinforce repaired cracks may be held in place by hand, pressing hard and sliding to squeeze out excess glue. When the glue cools, the cleat will be held in place by the gelled glue. Hide glue shrinks as it dries, and the cleat will be drawn tighter and will have sufficient strength in most cases." Doesn't match my experience. It takes very little downward pressure to squeeze the glue out by rubbing. Warm everything up, and use plenty of glue so there's a good pool around the bridge while you rub. After a couple seconds you'll feel a bit of roughness as the surfaces make contact, and then you only have a small amount of movement left before it sticks in place and can't be moved without a full do-over. So start with larger movements and progress to small as it gets close. The whole thing is over in about 3 seconds. As for strength, I'll have to run a test sometime, but I doubt it's much weaker (if any) than a clamped joint. The bridge on my redwood harp guitar has maybe 10 square inches of glue area, with lots of pointy bits for it to start peeling at, and has been fine for 2 years with 300lbs tension pulling on it and humidity ranging below 20% to above 70% throughout the year. And when we're talking softwood soundboards, the wood will peel long before full strength hide glue, so even a weaker joint would likely be more than enough anyway.

Author:	kencierp [ Sat Dec 05, 2015 8:58 pm ]
Post subject:	Re: Bridge gluing with no soundhole
Quote: In the article I read regarding rubbed joint on a classical bridge, the author said that this was actually the strongest bridge joint. Doesn't match my experience. I don't use HHG -- just sharing the comment of Frank Ford who has been considered one of the premier stringed instrument repairman since 1969. Perhaps Hesh has a view point or opinion for this no clamp rubbed glue application concept?

Author:	PeterF [ Sun Dec 06, 2015 3:49 am ]
Post subject:	Re: Bridge gluing with no soundhole
DennisK wrote: kencierp wrote: I recall reading this from Frank Ford: "Because it sets as it gels on cooling, hide glue can be used for “rubbed” joints where maximum strength is not required. Patches or “cleats” used to reinforce repaired cracks may be held in place by hand, pressing hard and sliding to squeeze out excess glue. When the glue cools, the cleat will be held in place by the gelled glue. Hide glue shrinks as it dries, and the cleat will be drawn tighter and will have sufficient strength in most cases." Doesn't match my experience. It takes very little downward pressure to squeeze the glue out by rubbing. Warm everything up, and use plenty of glue so there's a good pool around the bridge while you rub. After a couple seconds you'll feel a bit of roughness as the surfaces make contact, and then you only have a small amount of movement left before it sticks in place and can't be moved without a full do-over. So start with larger movements and progress to small as it gets close. The whole thing is over in about 3 seconds. As for strength, I'll have to run a test sometime, but I doubt it's much weaker (if any) than a clamped joint. The bridge on my redwood harp guitar has maybe 10 square inches of glue area, with lots of pointy bits for it to start peeling at, and has been fine for 2 years with 300lbs tension pulling on it and humidity ranging below 20% to above 70% throughout the year. And when we're talking softwood soundboards, the wood will peel long before full strength hide glue, so even a weaker joint would likely be more than enough anyway. Doesn't a pool of glue around the bridge mess with the finish or is it a lot easier to clean up than other glues? I've never used hide glue. Sent from my GT-I9300 using Tapatalk

Author:	Colin North [ Sun Dec 06, 2015 8:22 am ]
Post subject:	Re: Bridge gluing with no soundhole
Not really difficult to clean up at all, a bit easier than TB. Gels as it cools (first time it took longer than I expected it would to actually get "rubbery"), remove gently with a chisel edged soft wooden stick, wipe off traces left with warm water, e.g. smallish paint brush/cloth to dry. Just practice it first, not on a guitar, several times until you get some confidence, it's much less stressful!

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Author:	Hesh [ Sun Dec 06, 2015 8:38 am ]
Post subject:	Re: Bridge gluing with no soundhole
Not to be disagreeable but you won't see us, folks who reglue bridges every week using a rub joint with HHG to reglue a bridge.... First repairs can be a bit different in so much as we may be dealing with top distortion, a torn-up top under the bridge damaged from when the bridge lifted, and/or dome topped instruments where the bridge needs some clamping horsepower to be completely down and have wood-to-wood contact everywhere. Rub joints with HHG have been widely used by classical makers but there is a lot of difference in string tension between classical and steel strings. Classical guitars often have very flat tops, not so with steel strings most of the time. Frank's advice is rock solid and thanks Ken for posting that. He uses rub joints for cleats and cleats are not under string tension so it works fine and I do this too, frequently and/or use small magnets to hold the cleat in place until the HHG grabs. But a bridge is a different matter. Again the top will be expanding and contracting, possibly lots of string tension for the rest of time (for the instrument) etc. and domed tops all can combine to require clamping for bridges. In the repair world with damaged tops, top distortion, etc. a rub joint for a bridge would be a very poor practice.... Notice too that Frank qualifies his rub joint against the idea that it's not intended for anything that is under a lot of tension or stress. And that is something that I could not agree with more. I'll add that an insufficient method of gluing a bridge and a WRC top can lead to heart ache.... in so much as bridges and WRC like to combine to result in lots of wood fibers lifting when the bridge lifts. So regardless of top material gluing on a bridge properly is important or you will be paying the piper so-to-speak.

Author:	Hesh [ Sun Dec 06, 2015 8:48 am ]
Post subject:	Re: Bridge gluing with no soundhole
PeterF wrote: DennisK wrote: kencierp wrote: I recall reading this from Frank Ford: "Because it sets as it gels on cooling, hide glue can be used for “rubbed” joints where maximum strength is not required. Patches or “cleats” used to reinforce repaired cracks may be held in place by hand, pressing hard and sliding to squeeze out excess glue. When the glue cools, the cleat will be held in place by the gelled glue. Hide glue shrinks as it dries, and the cleat will be drawn tighter and will have sufficient strength in most cases." Doesn't match my experience. It takes very little downward pressure to squeeze the glue out by rubbing. Warm everything up, and use plenty of glue so there's a good pool around the bridge while you rub. After a couple seconds you'll feel a bit of roughness as the surfaces make contact, and then you only have a small amount of movement left before it sticks in place and can't be moved without a full do-over. So start with larger movements and progress to small as it gets close. The whole thing is over in about 3 seconds. As for strength, I'll have to run a test sometime, but I doubt it's much weaker (if any) than a clamped joint. The bridge on my redwood harp guitar has maybe 10 square inches of glue area, with lots of pointy bits for it to start peeling at, and has been fine for 2 years with 300lbs tension pulling on it and humidity ranging below 20% to above 70% throughout the year. And when we're talking softwood soundboards, the wood will peel long before full strength hide glue, so even a weaker joint would likely be more than enough anyway. Doesn't a pool of glue around the bridge mess with the finish or is it a lot easier to clean up than other glues? I've never used hide glue. Sent from my GT-I9300 using Tapatalk Peter my friend HHG is a joy to clean up. First wait about two minutes and it will jell into a SLS (snot like substance... ) not unlike the stickum used when we receive credit cards in the mail. This can be pulled off in very large...... snot like pieces..... And yes full grown men have been known to hang HHG boogers from our noses and get someone else's attention..... Next some warm water on a paper towel and maybe a toothpick or two to get into the corners and HHG cleans completely off easily. This is true the next day too with warm water again being used.

Author:	ernie [ Sun Dec 06, 2015 9:27 am ]
Post subject:	Re: Bridge gluing with no soundhole
I use a small toothbrush with warm water , some paper towels and a 45 deg tapered soda/plastic straw to clean out the crevices where tiny bits of HHG have gelled. I don/t use toothpicks for fear of marring my french polished tops. I would use a toothpick on a reglued bridge with a very well worn top

Author:	jfmckenna [ Sun Dec 06, 2015 9:33 am ]
Post subject:	Re: Bridge gluing with no soundhole
So there is no side port either? Nothing to get your hand in with? I would suggest using jacks on the inside if you can, if you can't then the vacuum clamp is the best answer though a high cost procedure for something you may only ever do once. It's not unheard of to use CA and glue the bridge right to the finish.

Author:	bftobin [ Sun Dec 06, 2015 9:47 am ]
Post subject:	Re: Bridge gluing with no soundhole
Haven"t tried it myself, but locating pins and a go-bar deck comes to mind. Brent

Author:	Bryan Bear [ Sun Dec 06, 2015 10:33 am ]
Post subject:	Re: Bridge gluing with no soundhole
You could also do an access port in the heel.

Author:	Sondre [ Sun Dec 06, 2015 10:54 am ]
Post subject:	Re: Bridge gluing with no soundhole
I glued the bridge on a prototype with epoxy and no clamps. Worked great. Not very repair friendly though..

Author:	Hesh [ Sun Dec 06, 2015 11:01 am ]
Post subject:	Re: Bridge gluing with no soundhole
Sondre wrote: I glued the bridge on a prototype with epoxy and no clamps. Worked great. Not very repair friendly though.. And not a great glue to use for other reasons beyond serviceability. Epxy is thick and has high dampening making it not a good choice for something as critical to preserving and passing on vibration as a bridge. Repair folks will ONLY resort to epoxy when a top is terribly torn up and there are lots of gaps to fill. Epxy still needs to be clamped as well.

Author:	Hesh [ Sun Dec 06, 2015 11:05 am ]
Post subject:	Re: Bridge gluing with no soundhole
bftobin wrote: Haven"t tried it myself, but locating pins and a go-bar deck comes to mind. Brent My go-bars exert 7.5 pounds of clamping force each and I would need a bunch of them to do a bridge wanting one very 1/2 inch or so. Say this means 10 go-bars and represents the same force as a 75 lb weight placed on the center of an unsupported top. Not unlike having a child sit on your guitar.... I love using the go-bar deck but there has to be a back stop or stuff happens.... Maybe pressurize the top? Or fill it with bondo? It won't sound very good but that bridge will be on....

Author:	Hesh [ Sun Dec 06, 2015 11:09 am ]
Post subject:	Re: Bridge gluing with no soundhole
jfmckenna wrote: So there is no side port either? Nothing to get your hand in with? I would suggest using jacks on the inside if you can, if you can't then the vacuum clamp is the best answer though a high cost procedure for something you may only ever do once. It's not unheard of to use CA and glue the bridge right to the finish. Rick of Turner Renaissance Guitars is known to use poly finishes AND CA glue to glue on his bridges directly to the finish. It works for Rick because cat poly is as tenacious a finish as I have ever encountered. I would not try this with any other finish mind you but if cat poly is in your future for this one it's an option and a good suggestion. IIRC correctly Rick is a stickler for quality CAs too and I think that I recall him liking Satellite City products and I like them too.