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Getting ready to close the box and wondering if anyone has done it “upside-down” with Go-Bars? Place the top on a dish in the deck, then the sides on top. Then clamp the sides down onto the top.

Could even put the other dish on top and use that as a giant caul.

Would that work? Anyone done it that way?

Could work, but having it above permits better access and vision to the glue joint and it's easier to wipe up glue squeeze out on the sides. In my case, the 15' dish is the caul, when doing the top, and, vice versa for the back (28').

Seems like using a dish as a caul would not give even pressure - the dish is too stiff and would bridge over small areas that needed more local pressure. The caul I use is a guitar shaped donut of 1/4" plywood - the center is out to allow the needed flexibility around the edges without putting any pressure on the dome in the center.

Ed

ruby@magpage.com wrote:Seems like using a dish as a caul would not give even pressure - the dish is too stiff and would bridge over small areas that needed more local pressure. The caul I use is a guitar shaped donut of 1/4" plywood - the center is out to allow the needed flexibility around the edges without putting any pressure on the dome in the center.

Ed

Didn't even think about that; Ed is right -- the dish as a gluing caul really isn't a good idea. I do exactly what John describes below (I paid attention in class, John). :-)

there is a point you have to consider. Once you brace the top the radius of the dish may not be what the top radius actually is here is how I do it on the Go Bar deck
https://www.youtube.com/watch?v=M8qAvQ5ExSE

This all makes sense. Was just curious why I never see it the other way. Now I get it.

John, doesn't adding the foam take away some of the clamping pressure because the clamps (or caul in this case) just squishes the foam instead of pushing the wood underneath it?

Another reason not to use the dish as a caul - if you glue with the plate in the dish and put the rim on top of it, you stand a chance of glue dripping onto the sandpaper of the dish and ruining it. I learned this the hard way when I used my fretboard radius beam to clamp MOTS onto a fingerboard and the glue crept onto the beam. Thanks goodness for naptha

Ed

I used radius dishes top and bottom when I glued my 3rd guitar. Seemed to work okay. I did take precautions. I msde sure the edges were propefly sanded to the rsdius and I got full contact all around. I put waxed paper on the bottom disk to protect against drips. I had the edge I was gluing on top. After gluing the top, I turned it over so the back was on top and checked for full contsct with the back's radius dish beforegluing.

the foam actually helps to apply even pressure and it is protective to the top in case a go bar gets away from you.

Ok. So trying to get this step done without having to buy anything. Tell me if this seems like it is a good plan.

I have a bunch of floor foam from costco (the kind that are like a puzzle and go together. So I would place one of those on top of the top. I do not have any large piece of wood to cut a caul the shape of the guitar, but have a ton of small pieces of scrap. I would put those all around the rim on top of the foam, being sure to position it directly above the gluing surface. Then go-bar it down.