I'm with Fred -
I have visions of imploded tops - all that pressure on the center of the top.
. Clamps with cawls just work too well to go a different route.
| Official Luthiers Forum! http://luthiersforum.com/forum/ |
|
| Anyone use go-Bars to glue a bridge? http://luthiersforum.com/forum/viewtopic.php?f=10101&t=27197 |
Page 1 of 2 |
| Author: | Blain [ Thu Apr 29, 2010 10:51 am ] |
| Post subject: | Anyone use go-Bars to glue a bridge? |
I've never heard of anyone using go-bars to glue a bridge, but it seems like it would make things easy as long as it is suitable for the job. Just put some alignment bridge pins in and glue it up. Seems cleaning up squeeze out would be a breeze too. Is anyone doing this already? Any good results? Any reason why this should not be done? |
|
| Author: | Daniel Minard [ Thu Apr 29, 2010 11:11 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
If you were going to do this, you would have to support the top to prevent it distorting under the pressure of the go-bars. Tempting, but I wouldn't risk it. Vacuum or deep C clamps are the way to go IMO. I use the Stew-Mac clamps & like to get five (or more) of them in place for even clamping pressure. Seems excessive, but I have had a few bridges lift & this method has cured the problem. |
|
| Author: | Fred Tellier [ Thu Apr 29, 2010 11:22 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
That sounds like a disaster waiting to happen, top damage potential is high. Fred |
|
| Author: | Tom West [ Thu Apr 29, 2010 12:08 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Charlie Fox type clamp,very simple,easy clean up,self aligning,works like a charm. Easy to make yourself. Tom |
|
| Author: | JJ Donohue [ Thu Apr 29, 2010 12:15 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Did it on 2 guitars. You need alignment pins, a bridge caul and jacks on the inside of the guitar to assure that the top doesn't distort. After 7 years, the bridges are still intact and the top is undistorted. The clamps and procedure touted by those above is more reliable and easier. |
|
| Author: | JohnAbercrombie [ Thu Apr 29, 2010 12:19 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Daniel Minard wrote: If you were going to do this, you would have to support the top to prevent it distorting under the pressure of the go-bars. Daniel is correct. Organizing a good support inside a soundbox is not always easy- it does help if you think about it before you close up the box. Once you have that worked out, there is no reason why go-bars could not do a good job for bridge gluing. Clamping bridges 'from the outside' is nothing new. Robert Bouchet (famous French maker of classical guitars) was known for his original jigs and fixtures. Bridge gluing was no exception. From his (very interesting) 'Cahier d'Atelier' (workshop notebook) the following pictures give a good idea of his bridge gluing setup. Cheers John PS- You have to buy that 'Cahier'- it isn't online - I looked! |
|
| Author: | Corky Long [ Thu Apr 29, 2010 1:12 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I'm with Fred - I have visions of imploded tops - all that pressure on the center of the top. . Clamps with cawls just work too well to go a different route.
|
|
| Author: | JohnAbercrombie [ Thu Apr 29, 2010 2:18 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Corky Long wrote: I have visions of imploded tops - all that pressure on the center of the top. . Clamps with cawls just work too well to go a different route. If your guitar top will implode, even with support from the inside, it will probably have difficulty handling the torque from several deep clamps twisting the bridge as you glue it. I notice that stewmac has 'levelling screws' to try to address this problem with their clamps. So, every method has its problems. Clamps and cauls do work OK, once you work out the caul for the inside (which, BTW in steel string guitars, never seem to support the bridge wings beyond the bridge plate), and the padding around the soundhole, and getting 3 clamps organized in the space available. You do want to have the bridge pinned in place, since the clamps try quite hard to torque it out of position. The question about how much clamping force should be required for a well-fitted bridge is another question entirely. Bouchet may well have been concerned about preserving/creating top doming with his method. Cheers John |
|
| Author: | Jeff Highland [ Thu Apr 29, 2010 2:21 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I did it on a number of instruments , before moving to vacuum clamping. You do need to prop the top under the bridge but this can be as simple as a couple of just slightly overlength posts. The back of the guitar should be sitting on the radius dish. You need a guard for the soundboard cut out just bigger than the bridge and split down the centre(so you can pull it apart for glue squeezout cleanup) Flat cauls on the thin bridge wings, rather than just a central go bar cause this area can cup Don't load it up with all the go bars you can fit It works fine, but I am glad I have gone to vacuum |
|
| Author: | JohnAbercrombie [ Thu Apr 29, 2010 3:01 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Jeff Highland wrote: It works fine, but I am glad I have gone to vacuum Jeff- I've done a couple with vacuum. What glue are you using and how do you organize the cleanup of squeezeout? That was a problem for me- perhaps I should have waxed the top/bridge to prevent the glue sticking? Also, for those considering vacuum-clamping bridges- I had the vacuum mess up a fresh FP finish on one guitar. I discussed this with Bob Garrish and we concluded that the vacuum was either pulling air through the Englemann top, or pulling oil/solvent out of the incompletely 'cured' FP. A word to the wise about being impatient! Cheers John |
|
| Author: | Jeff Highland [ Thu Apr 29, 2010 3:28 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Hot Hide Glue, Ran the vacuum for about 10 minutes, then cleaned up squeezout then another 10 minutes. |
|
| Author: | Blain [ Thu Apr 29, 2010 3:29 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Thanks for the replies. I'll get some supports for the inside and give this a try. It just seems like it will be much quicker to get everything set in place and still be able to clean up squeeze out easily. |
|
| Author: | Colin North [ Fri Apr 30, 2010 5:38 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I'm just imagining a go-bar slipping and spearing the top. I use 6" F clamps near the screw travel limits and/or wooden clamps with spacers over a deep caul shaped to the bridge shape to give enough clearance for cleaning glue squeeze out. |
|
| Author: | Laurent Brondel [ Fri Apr 30, 2010 8:49 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I am puzzled by the "why?". As others have noted, Murphy's law will dictate that at one time, maybe distant, maybe not, a go-bar will slip, or break, or bend the wrong way and ruin your top. Other things may go wrong, like the inside cauls cracking the back for example. There are so many other sensible methods of gluing the bridge. Bouchet's method is an "modern" adaptation of the Spanish method of using rope and wedges. At least with wedges or clamps one can control the down pressure, not so much with go-bars. I agree that the "Cahiers d'atelier" is a must read, at least for those attracted by the high craftsmanship/low-tech realm. To boot, the drawings are a hoot. What's wrong with making a bridgeplate caul riding the braces and using deep C-clamps or cam clamps? |
|
| Author: | Chris Paulick [ Fri Apr 30, 2010 9:53 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Here is a discussion from when I ask the same thing. viewtopic.php?f=10101&t=22088&hilit=Gobars+for+gluing+on+bridge I ended up using a vacuum clamp I made. I made one vacuum clamp to place the pinless bridge and put some staple pins in the top and pressed the bridge down over the pins then removed the locating clamp and glued the bridge down with the vacuum clamp and the pins prevented the bridge from sliding. |
|
| Author: | Mike OMelia [ Fri Apr 30, 2010 10:18 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
http://www.lmii.com/CartTwo/thirdproduc ... dge+Clamps This thing is SO easy to use, no potential to damage the top, makes for cleaning squeeze out a snap. Remember to use thin wood scraps for the pressure bolts to bear down on. It even worked great on my harp bridge. Mike |
|
| Author: | Chris Paulick [ Fri Apr 30, 2010 10:48 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Won't work on pinless bridges or access through F holes though. But other then that it's fine. |
|
| Author: | george wilson [ Fri Apr 30, 2010 3:18 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
We used go bars(much larger size) to glue bridges down on harpsichords in Colonial Williamsburg. One time,my 2 journeymen and I were applying go bars to the bridge of a large harpsichord,and one of the guys slipped and broke a hole through the soundboard. That pretty well ruined it !!! |
|
| Author: | P@uL [ Sat May 01, 2010 12:37 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
sounds like gluing on a bridge with go sticks has been done but i don't think i would ever do it. on a nearly finished instrument one of those sticks pops loose and its going to do some damage. |
|
| Author: | Chris Paulick [ Sat May 01, 2010 1:29 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I would think that it wouldn't hurt to protect the top around the bridge and to remember that you don't need all that much pressure. The lining is clamped with close pins and how much pressure is that? The bridge is pretty much held down by the strings except for a pinless bridge. I had a guitar in for repair and it looked like the bridge was beginning to lift at the back and it was completely unglued which I found out when I doffed the strings. I think it's another choice to have and not one to be dismissed. Heck, I think you could just put some CA on it and just lay some lead shot filled bean bags on it if you wanted too. In answer to the topic question. Yes, there are people using gobars to glue on bridges. Just be aware of the caveats involved with doing it. |
|
| Author: | JohnAbercrombie [ Sat May 01, 2010 1:29 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
P@uL wrote: sounds like gluing on a bridge with go sticks has been done but i don't think i would ever do it. on a nearly finished instrument one of those sticks pops loose and its going to do some damage. I agree-it can be done, but I have enough mishaps with go-bar sticks that I wouldn't try it myself. Really- if you need a lot of clamping pressure in a normal bridge gluing situation, probably there is a problem with the fit/radius of the bridge. A technique I don't see mentioned often, which does work if the bridge is properly fitted, is to use some good-sized rare earth magnets (in pairs) - under the soundboard and on top of the bridge. (another 'trick' from Sergei deJonge's building course....) Cheers John |
|
| Author: | Chris Paulick [ Sun May 02, 2010 8:01 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I have some 1" X 1" X 1/4" neo magnets I use for clamping things at times and they can give your fingers a nice bite if you aren't careful too. 
|
|
| Author: | Ti-Roux [ Sun May 02, 2010 8:52 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I really like the big note in red in the bouchet' notes: NE PAS COLLER À L'ENVERS (Don't glue wrong way) |
|
| Author: | JohnAbercrombie [ Sun May 02, 2010 12:44 pm ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
Ti-Roux wrote: I really like the big note in red in the Bouchet' notes: NE PAS COLLER À L'ENVERS (Don't glue wrong way) Yeah, I liked that as well!!  I guess that even Bouchet could make a 'stupid mistake' on occasion!It's a very interesting book- we should try to put together a 'group effort' of bilingual folks (and semi-bilingual , in my case) to produce an 'unofficial English translation' of the 'Cahier' notes. The drawings tell a lot, but the written notes are very interesting and informative. It takes a while to get used to his handwriting, the Euro way of writing 1's and 7's, etc. but it's worth it. Too bad the book is so $$ to buy (about $70 Cdn with shipping from Fr.) Cheers John |
|
| Author: | WilbPorter [ Mon May 03, 2010 8:13 am ] |
| Post subject: | Re: Anyone use go-Bars to glue a bridge? |
I have used gobars on three guitars to glue on the bridge. The bridge has to fit nicely to the top in a dry fit. And you need cauls on both the back and top with adjustable columns ( for me small turnbuckles). Then seat the guitar back in your sanding dish. And your ready to go. I position the bridge and then use yellow glue to glue tiny blocks to keep the bridge in position. In half a minute, your hot hide glue is on and you're done. Incidentally, in my assembly room ( just my fancy name for a small untidy humidity controlled room ) I use the ceiling for the top of my go bar deck. Great visibility. Using birch go bars! |
|
| Page 1 of 2 | All times are UTC - 5 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|