Tools for Clamping top and back

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Guitar Hack
Posts: 43
Joined: Tue Aug 17, 2010 7:44 pm

Tools for Clamping top and back

Post by Guitar Hack »

I didn't have a lot of those clamps most people use to clamp the sides so came up with my own idea. I made two wood frames about the size of the outermost portion of a dreadnaught. When it was time to glue up the back or top I put one of these on each side and then used regular clamps. Seemed like a lot more sense and easier than using what is usually used. It worked like a charm. The frame seems to roll as needed to conform to the slight curve of the top or back.
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naccoachbob
Posts: 477
Joined: Thu Dec 03, 2009 9:25 am
Location: Nacogdoches, Tx

Re: Tools for Clamping top and back

Post by naccoachbob »

Hack and Rick, I like that idea.
Currently I use rubberbands to do the top and back, because of the KMG mold that I'm using. Do you think a caul such as these would be overkill with that? Or would it be fine?
Bob
deadedith

Re: Tools for Clamping top and back

Post by deadedith »

Bob - I use the kmg band method also. As long as there is squeeze out all around, you'll be fine. I do put a padded piece of stock across the body at the headstock and tailblock sites and clamp down the stock. Peace of mind only
DaveB
bmasten

Re: Tools for Clamping top and back

Post by bmasten »

Looks good. I tried the go-bar deck the first couple times I tried gluing top/backs in place. Figured out real quick that wasn't going to work for me. Dented the top. Dented the back. Cracked a top (ended up trashing the whole top). Had a wood caul slip and not get any pressure in one spot and had to heat up and remove the top. Then there was the numerous flying yellow stick projectile problems. I finally went the route of spool clamps. Worked for me and I liked that I could see my clamping position and pressure from all angles. After researching the material cost and the time to make them I ended up taking the easy route and purchased 24 of them online for I think just under $3.00 each.
enalnitram

Re: Tools for Clamping top and back

Post by enalnitram »

bmasten wrote:I tried the go-bar deck the first couple times I tried gluing top/backs in place. Figured out real quick that wasn't going to work for me. Dented the top. Dented the back. Cracked a top (ended up trashing the whole top).
I had similar problems when I used rubber bands and clamps. I built a contraption and a part of it was pressing into the overhang of my top and cracked my top. my fault, a dumb mistake, but I have anyway since moved to go bars and have had good results with those. I make sure first that my top and back fit the sides, as well as I can make them. little or no pressure is required to get the top and back to fit the sides. this is key. my go bars were cut from fir, 1/8" by 3/8" and are sized to fit this procedure. i have various length go bars to go with various tasks.
kencierp

Re: Tools for Clamping top and back

Post by kencierp »

One of the tricks to making an accurate/successful top/back clamping caul is to make sure that it only contacts around/on the kerfing and rim edge and it flexes so it can conform to the back contour of the rim and back plate. Also, KMG Masterworks system uses screws rather than clamps -- the rim is supported inside the mold with leveler blocks.

http://www.kennethmichaelguitars.com/masterwork.html
tippie53
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Re: Tools for Clamping top and back

Post by tippie53 »

There are so many ways to do this . I use my contour dishes . What makes this easy is that if you do a good job with the dry fit you can actually clamp this with your disks and a weight . I do not take a body out of a mold till the top and back are on.
You can use the cam clamps , press , anything but if you don't have a clean dry fit , you can have trouble no matter what the clamping system you choose . I will use bar clamps at the blocks first to set things up then go from there. Next time I glue up a body I will post vids and photos
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
kencierp

Re: Tools for Clamping top and back

Post by kencierp »

Ditto to John's point

What ever the clamping method if you find that you have to crush the parts together -- something is wrong.

When using rubber bands we find that just a few are needed to get glue squeeze out. One of the most common problems I see is that the back is not thinned properly to about .105" on average. Trying to get a .125"+ back plate to conform can be a problem.
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