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Hot Hide glue on Top and Back-How fast?
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=12585		 Page 1 of 1
Author:  Kirt Myers [ Mon Jun 25, 2007 1:45 am ]
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Hi all,

I'm getting ready to hot hide glue the back on my EIR dread cutaway. I'm planning on using 20 gobars around the perimeter. I've been practicing, but so far the fastest I can get all the gobars in position is about 2 minutes. Is this too slow? I will be preheating the rim and the back with a heat lamp before gluing.

I've been using a brush to apply glue to braces but I'm thinking a plastic squeeze bottle might work better for this.

Your opinions would be greatly appreciated.

Kirt
Author:  JJ Donohue [ Mon Jun 25, 2007 2:04 am ]
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Try making a batch of glue a little thicker so you can lay down a bead around the gluing surface. Brushing takes way too long.

You should be shooting for less than 60 seconds. Heating the surfaces as you've described is great.

Now...something else to consider. I've used HHG on 8 guitars now. On the next one, I'm going to use Fish Glue on the tops and back. You can relax and apply the glue in a much less frantic manner. My testing has shown similar results as HHG.

Good luck and I hope this helps.
Author:  Kirt Myers [ Mon Jun 25, 2007 2:42 am ]
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Thanks JJ,

I was afraid that was too slow. Actually I wanted to get down to about 40 seconds. I may have to have my wife hold things down on one end as I put clamps on the other. Looks like more practice will be needed.

I have heard many good things about the fish glue though, could be an option too.

Kirt
Author:  JJ Donohue [ Mon Jun 25, 2007 2:53 am ]
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Kirt...When I first glued tops and backs, I had 2 others help with the operation. Since I went to the thicker glue (another Mario recommendation), I can do it alone and it takes me around 45 seconds. Do lots of dry practice with the choreography and have everything set in place so you can minimize the motions required. Go live only after you gain confidence from the time-motion practice. Once you succeed, the next ones will be a breeze.
Author:  John How [ Mon Jun 25, 2007 2:59 am ]
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Kirt, here's how I glue a top or back on using hide glue.
I made a caul using 1/2" thick styrofoam insulation board in the shape of the guitar and them doubled it up just around the edges where it make contact over or under the sides. I place my concaved dish on the table and then the styro caul. The top or back goes on top of that and then finally the rim still in the mold. If it is the final plate to go on then you'll need the corresponding dish to support the weight of the clamps on top as well. These are just garden variety concrete flower bed borders from the Home Depot. It's extremely fast and works very well.

Author:  Marc [ Mon Jun 25, 2007 3:11 am ]
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Takes me longer than 60 seconds. This is what I do, although it works I'm NOT recommending it because there are easier ways, (fish glue).

I heat both surfaces with a heat gun, I raise the temperture in my shop to 90 degrees with a space heater(doesn't take long in my case, it's only 9 by 20 and well insulated), lay the glue on thick with a heated needled squeeze bottle. I then lay the back on quick to prevent evaportion. That all takes almost a minute, I then spend the next minute clamping with spool clamps. The squeeze-out remains clear and very liquid during that entire period.

Raising the shop temperature buys time.

I've glued six backs this way. I removed one once which convinced me they're stuck on good.

Oh, in my experience, test runs tend to be faster than actual runs, panic sets in.
Author:  WaddyThomson [ Mon Jun 25, 2007 3:18 am ]
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Not to steal the thread, but I should have been doing HHG in my shop yesterday.  91.8* in the shop.  97* outside.  High humidity, and the dehumidifier raises the temp in the shop by about 7 to 10*.. I need to invest in a window unit AC.   (Sweat not tears)
Author:  Colin S [ Mon Jun 25, 2007 3:25 am ]
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I always used to glue my top and back on with hide glue, the main thing was to get a good fit of the plate to the rims so that it only wanted to go on in one position with no gaps. heat up the plate and the rims, I used a hair dryer, (it's the only use I've got for one now!). Run the bead of glue round using a nozzle on the bottle, then firmly press the plate. Don't immediately try and put the go-bars on wait for the glue to grab then add the go-bars head and heel block then gradually fill the gaps. The mistake is to rush and let the plate gap in some points while putting the bars on another. If you just wait a little until the glue starts to grab, then it's much easier. Don't forget HHG will tighten the joint as it dries as well.

Notice that I said 'used to' I now always use Kremer fish glue for gluing the plates on now, much less rushed and more relaxed. On all the test to destruction experiments I've done with fish glue spruce/spruce, spruce/hardwood, hardwood/hardwood, it's always been the wood that has given way, never the joint.

Colin
Author:  crazymanmichael [ Mon Jun 25, 2007 3:26 am ]
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john beat me to it with the weights suggestion. it is much easier and less traumatic to your psyche than trying to get a lot of go bars in place.

i haven't tried his styrofoam idea though. will have do so on the next one.
Author:  John How [ Mon Jun 25, 2007 3:40 am ]
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[QUOTE=crazymanmichael] john beat me to it with the weights suggestion. it is much easier and less traumatic to your psyche than trying to get a lot of go bars in place.

i haven't tried his styrofoam idea though. will have do so on the next one.[/QUOTE]

The styrofoam just helps conform the plate to the shape of the side contour.
Author:  Kirt Myers [ Mon Jun 25, 2007 7:19 am ]
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Thanks for all the good info.

I'll think about this for a while and let you all know what I did.

Kirt
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