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| Using sanding dishes to glue on backs and tops http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=17017 |
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| Author: | Larry Drover [ Tue Apr 29, 2008 6:22 am ] |
| Post subject: | Using sanding dishes to glue on backs and tops |
When I glue on the back and top I sometimes find it necessary to to keep the rim in the mold to keep everything as square as possible....Gluing is made more difficult by do this....I have used cam clamps, cello clamps and the go bar deck in the past....I was wondering if anyone has used the sanding dishes as a clamping caul....sandwiching the guitar body between the two dishes and placing several clamps around the edges of the dishes. Will this work for me or against me?....Thanks,Larry |
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| Author: | jhowell [ Tue Apr 29, 2008 6:37 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
Larry-- That is essentially how I do it. My sanding bowls are glued to 24" square pieces of MDF. I place a riser box on my bench, then sandwitch the rim in the mold bwtween the cauls. Glue up and clamping can be done fairly quickly. The riser makes clamping easier. 
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| Author: | Bruce Dickey [ Tue Apr 29, 2008 7:05 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
Same as Todd here. But, Olson uses aluminum radius dishes as his clamping mechanism, much like the top photo. Frankly I like to be able to view all seams made by the process. I get to see glue squeeze out which confirms contact and to have a chance at some minor cleanup. Also, I use temporary glue blocks on my molds to perfect align the top or back while gluing. Since starting to do that, I've not had any registry problem or misalingment of back or top center seam with the rim. Then I tap the glued alignment blocks off the mold and clean those up a bit. I may go to a screwed on mechanism for alignment. Having the dishes on there would complicate alignment for me? |
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| Author: | Bill Greene [ Tue Apr 29, 2008 7:13 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
Yep, that's how I did my last guitar. Used the radius dishes as cauls, inside the gobar deck, and used multiple gobars to exert the proper amount of pressure. It was easy and worked like a dream. Many different ways to accomplish the same thing. |
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| Author: | JimWomack [ Tue Apr 29, 2008 7:30 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
I'd be worried that the radius dish might deform over time if used as a clamping caul. And while I like the gobar deck for glueing up bracing, it just doesn't work for me when attaching top and backs with hhg. I've settled on a series of clamping cauls that screw into my molds with coarse threaded eyebolts. I use 1/2 weather stripping to prevent marring of the wood and to spread out the clamping pressure. Attachment: 2.jpg I start by attaching the waist clamp first, then alternate top and bottom. I can get all the clamps attached in less than a minute without overly rushing the process. The holes for the eyebolts are overly large to allow the caul to conform to changes in inclination. Works for me, anyway. Attachment: 4.jpg
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| Author: | Hesh [ Tue Apr 29, 2008 7:30 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
I also flatten my upper bout so the dish is no longer a precise fit, not that it ever is anyway...... And I agree that I too am pretty paranoid about wanting to see the entire glue joint and a dish on top would make this more difficult. I use a go-bar deck with individual 1" X 1"ish scraps of wood to prevent the go-bars from denting the top or back and the go-bars also take up the slack in the height differences. I also use a go-bar deck that rotates 360 degrees making inspecting my joint....... very easy to do. I think that some of the folks who glue on tops and backs with HHG will go the clamping caul route, possibly using a dish, because if properly thought out and executed it is probably the fastest way to set the clamps or weight down the process. Attachment: DSC00886.jpg
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| Author: | JJ Donohue [ Tue Apr 29, 2008 8:21 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
I use a caul similar to Todd's and gobars with HHG. On future builds, I'll be trying Fish Glue for the plates. I expect that the increased open time will be a welcome change. |
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| Author: | Colin S [ Tue Apr 29, 2008 8:42 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
I use the 15' (back radius) dish when gluing on both the back and the top. The back is sitting in the dish and the sides, with the fish glue applied, are placed onto the back, then I use small hardboard caul on the rims, as shown below. This allows easy access for glue clean up inside the body. Attachment: Back gluing.jpg For the top, back sits in the 15' dish and the top is glued in place, again using the hardboard (I think you call it masonite?) cauls. Attachment: Top gluing.jpg Colin |
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| Author: | Todd Rose [ Tue Apr 29, 2008 8:53 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
I use my radius dishes for gluing on tops and backs. I only use one. For example, when gluing on the back (which I do first), I apply glue to the rim, position the back on the rim, tape it in place with a few pieces of tape, flip it over so the back is on the bottom, place it on the dish, then put go bars directly onto the linings on the top side of the rim. Works great. Simple. Easy. No problems. I do the same for the top, putting the go bars directly onto the back, over the linings. I have not seen any need for a caul between the go bars and the guitar. |
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| Author: | stan thomison [ Tue Apr 29, 2008 9:01 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
Took dishes and cut them to an little oversized dred shape. I first glue the back on and tape it in place. I then set it in the press, on a dish that is in the press perm. and then set the body (in mold) into the press. Put glue on the rim, set top on and tape it. Then turn press to glue the back and top on at same time. I make sure as I do the press that everything has stayed in place and not slide of center. One more reason I guess pretty anal about my brace tucks being tight and no seperation from the pieces to the rim. 45 Min to hour done and after a little cleanup (very little) into the binding rig. I used to use the go bar setup and also cam clamps. I learned and did this method at Bourgeois and found it easier and faster FOR ME anyway. |
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| Author: | letseatpaste [ Tue Apr 29, 2008 11:04 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
I've done it on one guitar and it worked out real slick and quick. I did put in a layer of cork just to distribute pressure at least a little bit. The cork was cut out just to cover the perimeter of the guitar so all the clamping pressure is at the rims and blocks. Check out how George Lowden does it. It's a bicycle innertube fastened to a piece of plywood with fabric.  
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| Author: | Andy Matthews [ Tue Apr 29, 2008 11:16 am ] |
| Post subject: | Re: Using sanding dishes to glue on backs and tops |
Personally I wouldn't use the dish as a caul in this situation, as I'm trying to apply clamping pressure to the top or back only over the linings/edge of sides. I do however sit the guitar in the opposing dish when attaching either of the plates - supports the rims/boat properly. |
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