Official Luthiers Forum!

The current build is my first with HHG. The braces and everything else have worked out great, and I'm ready to attach the top.

I'm hung up though on actually pulling the trigger and heating that glue for this as even after practicing for an hour last night, I'm still not confident I can spread the glue on the lining, place the top in position and clamp it all down in under 45 seconds.

I've got the go-bar deck ready, and I've also practiced with placing weights on the top as an alternative method.

Could someone please describe their process for this tricky glue up?

Thanks

Dave

Dave...It takes too much time to "spread the glue along the linings". Instead, lay down a bead of slightly thickened glue on the linings and slap on the top. Using thickened glue and having the right bead size is somewhat important. You can do this in 15-30 seconds. I still keep the surfaces warm.

Good luck!

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JJ
Napa, CA
http://www.DonohueGuitars.com

Use a bottle with stainless nuts in it to keep the glue warm. Make sure you have the top registered with wood bits so it just pops on with no adjustment needed. If you need to adjust it, your ruined.

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Here is what a Parlor Guitar is for!
http://www.youtube.com/watch?v=oEa8PkjO6_I

I know several builders who use hide glue for everything except this operation. For gluing the top and back on, they use LMI white or titebond. I know of several builders who are experimenting with fish glue. Fish glue seems to have the same properties as hide glue but it is a liquid and has a very long setup time. It's on my short list of things to try.

Registration pins will definitely help. I bought some 1/16 brass rod at a hobby store that I use for this very purpose. I've cut two little pieces about an inch long and I camphered the ends for easy penetration. You can drill in the neck block, under the fingerboard but make sure to clear the channel for the truss rod (don't ask me why I know this...).

If your pockets and braces are very tightly fit, you might not need to register the tail-end, but if you do, try this; dry fit your top (or back) and clamp it down. Then you can glue (HHG) a little piece of scrap wood to the rim flush under the top and you can drill your registration hole in the overhang and very easily chisel this little piece off after the glue-up.

Heating the rim and back with a hair blower can buy you a few seconds as well.

I use HHG everywhere except for this part. I glue the back on first using titebond for the easy clean-up, and on the top, I use fish glue. I'd use the fish glue for the back as well but I just find it too hard to clean up. Those long filaments just drive me mad! Awesome glue, though. Dries as crystal hard as HHG and from the litterature on the bottle (Lee Valley) is reversible as well.

Good luck.

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

There is a similar problem using HHG for gluing classical backs.

I heat the back and the linings with a hot air gun. I raise the room temperature to 85-90 degrees which is easy for me with a space heater because I work in a 200 sq foot room. I run a thick bead of glue quickly then put the back on. Once the glue is covered with the back it slows the drying a little so I have more time to clamp with spools. Start to completely clamped takes a couple of minutes.

Raising the room temperature and a thick bead are the most helpful for extending time. Drawback is there is no time to worry or do anything about the excessive squeeze-out from a thick bead.

Lose the spool clamps...use the much faster gobars to get it all clamped within 20 seconds.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Lose the HHG and no need to stroke out...........

Thanks everyone for the ideas.

Your responses show that this is 1) not easy and 2) needs to be done quickly.

It makes me really wonder what the process was before white glue was invented.

Are there many of us using hhg for the plates?


d

Yeah, I vote for Fish Glue. That's what I used to glue my back on. Worked great. It's lasted a whole 2 months, so far, without coming apart.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

I use Hide glue for everything on my guitars except this. For gluing the top and back plates on I use fish glue, same end result as the Hide but without the panic!

There is a more relaxed method of using the Hide glue, which is tried and tested by the 19th century builders, Torres included, that I have described before, I keep meaning to try it but......

Spread the hide glue on the rims fit the plate in place on the rims. Now, with a small mop spread alcohol around the surface of the plate above the rims. Set fire to the alcohol, then as it burns and heats up the plate and the glue underneath it rope or otherwise clamp the plate in place. The heat of the burning alcohol softens the hide glue and hey presto you've got a perfect joint.

Do you remember the picture of Joshua's burning guitar? Well that was a failed attempt at gluing on the back.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

I trust that this is another example of "Dry English Humour."

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Steve Walden
Aspiring Builder,
Bartlesville, OK

Larger instruments such as cellos, basses, pianos, etc., would commonly use a hot room. Heat a small room to 120F, and you have all the time in the world. Actually, for most bloom strengths you would only need 100-110F to stay above the gel temp. It sounds hot, but given that a sauna is typically in the 170-180F range, 110-120F is not that bad to work in for a few minutes.

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Eschew obfuscation, espouse elucidation.

Actually the heated room is an old Martin trick. In the old north street plant they'd save up their larger span gluing and heat up an area (close the windows etc.) even in the summer
and create an ideal gluing temperature. Nobody nearby liked it much but it was the way to go
for HHG. When they went to lacquer they also had to come up with tricks to deal with humidty.

I also vote for fish glue, have had great results with top and back gluing and find my stress level greatly reduced. There is nothing like realizing you are just about at the point where HHG is about to go on you and your not quite happy with the joint. I like the pin idea, I index with
braces through the linings and that works to. Still like fish glue though

Best
Bruce

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Bruce Herrmann
"What lies behind us and what lies before us are tiny matters compared to what lies within us."

That not really hot. That's summer in New Mexico.

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Aoibeann

David in the hot room do they also maintain 45ish RH?

Not in any shops I know of. I'd bet you're usually looking at the 25%-30% range. If the woods are just brought it to warm shortly before gluing though, then removed (or the heat turned down) a few hours after clamping there shouldn't be any problems.

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Eschew obfuscation, espouse elucidation.

No, the method was a commonly used one. And, yes Joshua and I have been daring each other to try it, but I might have been fibbing a bit about that one of his .

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

You simply have to be well prepared. When I had my week-long student here some years ago, this was one of the things he dearly wanted to see done. He timed it, also. From the start of applying the hot hide glue to the last go bar was under 45 seconds. Plenty of time, no tricks needed.

Just be well prepared, and do as many dry runs as necessary for you to be comfortable with the process.