Official Luthiers Forum!

Hi everyone!

I'm ready to close the box on my first acoustic work (a ukulele, based on classical guitar, with spanish heel, etc..).

I always worked with the method of applying a thin film of glue on both surfaces I want to glue. (PVa glue)

So, now, i'm wondering how to apply glue to close the box. I checked Cumpiano, He apply glue only on the kerfing and the brace pockets. Are you doing the same? Have you other methods?

Thanks!
Francis

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Francis Richer, Montréal
Les Guitares F&M Guitars

I apply it only to the lining/blocks/side/brace pockets

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John Mayes
http://www.mayesluthier.com

If you're installing binding later, then the kerfing is all that matters since the side material will be mostly routed away. Applying glue to both surfaces does seem better, especially on an ukulele where there's a lot less surface to deal with, and thus less time for the glue to start setting up.

As for my methods, I use spool clamps. Put them on all the way around the box, and remove a few at a time and squeeze glue into the gap, until I've made a full lap around the box. But that's a full size guitar. On an uke you could put the glue all around, stick it on, and then apply clamps, like on a violin.

Oh, and I use hide glue. One of the nice things about it is that it can melt and stick to previously applied glue. You can put a thin coat on one surface and don't worry if it dries, and then when you put hot glue on the other surface and push them together, you get an instant glue-on-both-surfaces joint Or in this case of squeezing glue into the gap, I had previously applied glue to both surfaces (and let it fully dry so it wouldn't sticky the gap closed until fresh glue was squeezed in).

My last 3 I used Fish glue on the lining, blocks and brace pockets, don't use to much, as long as there is a thin layer of glue it will hold and there will be very little squeeze out. The nice thing about fish glue it does not require a lot of speed, but it is very sticky on the fingers, so keep a damp towel around to wipe your hands on. The more I use fish glue for the more I like it.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Yup, fish glue applied with those little brushes.

I use fish glue on the linings and brace notches too. I have found a 3/4 or 1" (cheap) artist's brush the best thing to use. It holds plenty of glue & a light wipe cleans up any excess.

Thanks for the replies guys!

I'll give you some news of this tomorrow!

By the way? Why using HHG or Fish glue instead of PVA?

Thanks!
Francis

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Francis Richer, Montréal
Les Guitares F&M Guitars

HHG under 3 minutes. He has it down.
HHG is a strong bond if done correctly and holds up to heat well and dries hard and actually pulls wood together when drying and is reversable for repairs and is a very old and proven glue and cleans up with damp rag.

Filippo and all,

At the risk of a highjack, what is the process for releasing fish glue (neck resets, or undoing a mistake)? Same as HHG? Steam?

I use HHG, and agree that it takes some care and prep to work fast enough so that you clamp up before the glue gels. So far, by heating the pieces being glued with a heat gun, I've had good luck with HHG, but I'm intrigued by a more forgiving alternative.

Thanks.

I did the last two boxes with fish glue. Used a cheap 1/2" artists brush to apply glue to the linings, blocks and pockets. Like someone said, you don't need a whole lot. Works great.

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Steve Smith
"Music is what feelings sound like"

I used HHG for all joints on my first 10 guitars. On the tops and backs...Lay down a bead, slap on the plate and clamp in the gobar deck...all within 60 seconds. They have all worked fine.

For my latest 10 guitars I used Fish glue for tops and backs. Lay down a bead, answer the phone and take a message, warm up my coffee...then slap on the plate and clamp in the gobar deck...all within up to 15 minutes...or so. They also have worked out fine. Just learn how big the bead should be to control squeezeout.

I still use HHG for braces, and bridges and will continue to do so because I prefer HHG's cleanup properties.

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

I have experience here. You do not want to have to take off a back glued with fish glue. It is much harder than HHG to release, and you must get moisture in the joint, and use lots of heat. The other option, is to place it in a hot damp closet for several months, and it will release on it's own (Ask Dave White about this!) I replaced the back on one of my builds, and in removing the back, I trashed all of the braces, as I couldn't get the glue to release, and I didn't want to trash the back by using too much heat along the join. That was where the braces got trashed. Total wood breakage. HHG willl break. Fish Glue does not seem to do that. Maybe not quite as brittle. when I tested the glues dried film, Fish glue was more flexible than either HHG or LMI White. Both of those tended to break, or snap when the film was flexed. Fish glue had a tiny bit more flex. And, FWIW, OBG (Hide glue with Urea), was like rubber.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Yeah, I suppose for the first couple using Titebond is a good choice since it's good to have around the shop for gluing up other projects and there isn't any other equipment needed like a heating pot and no mixing and shelf life not to mention smell(but I have a jig for that ) but I think seeing Mario's video shows having everything right at hand and ready to go takes away some of the fear of using it to close the box.
Interesting what Waddy said about the back and the closet. That might be one for HHG as a long and proven glue for lutherie.

I should have said I'm planning on moving to HHG at some point. I already use it for plate joining, braces, bridges, and other things but just haven't tried to close the box with it yet although I'm pretty sure I could get it done in time.

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Steve Smith
"Music is what feelings sound like"

Waddy...If I remember correctly, this was Dave's daughter's guitar and it sat in the closet of a flooded apartment where the humidity was 100% for an extended period...not your average hot, damp closet. In the end, I believe that Dave had to re-do almost every joint on the guitar...but he rescued the instrument.

Conversely, I, along with Colin Symonds and I'm sure others subjected joint samples of various glues to steamy shower-humidified bathrooms over repeated cycles (30 in my case) and never found any deterioration nor slippage of joint strength. It was the final test that convinced me to use FG. While it's not perfect in every category, FG has its pros and cons. I'm willing to trade off its more difficult cleanup and removal for the benefits of strength and ease of use.

I also removed a back glued with FG. It was tenacious and required moisture as well as heat as you reported. It took more time than HHG but in the end, I was able to remove it intact. I'll continue to use FG because I believe that its resistance to creep is similar to HHG and as a result, I have more confidence in those glues than I do in PVA glues.

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

JJ,

How do you know fish glue is resistant to creep? I have heard that too, and agree that it is probably true but since there are confirmed accounts of fish glue completely releasing in high humidity environments (Dave White's and another from a local builder here in a much less extreme situation than Dave's) I think it makes sense that a joint could soften enough to creep but not release and then re-set once the humidity went down. How much stress was on the joint in your bathroom experiment?

I used fish glue for a while but have switched back to LMI white for closing the box. I do not use the radius dishes for the top and back so the process takes me a bit longer to close it up and I don't have confidence I could get it clamped close to fast enough with HHG. Maybe I could do it in sections like a double bass but I don't really want to.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

I had 3 coupons (1x2) glued about 3/4 of the way and the edges clamped such that the force was acting in shear. These remained clamped for the full 30 day cycle and showed no difference than HHG. That was my intended end point. This was a rough and uncontrolled test and neither scientific nor conclusive... but...If I were to re do something like this again, I would subject samples to conditions that would generate failure and try to observe differences in time to failure.

There is one issue I reported about FG some time ago...the issue of solids settling out and lower bond strength. I was able to generate failures using my glue as received from Norland and unstirred. I compared this to samples bonded from the same container after significant stirring and there was a striking difference. So here's what I've done since that time:

1) Stir the hell out of the mother batch and transfer some into a 2 oz working container. I actually rotate the container in the shop to keep the solids agitated and in suspension.
2) Refrigerate the mother batch and use the 2 oz. (daughter) in the shop. High viscosity (cold) glue won't settle out.
3) Periodically thaw and transfer to the daughter...about each 2 weeks for me lately.

So far (after 1 year) I have had no bonding problems and it works as advertised.

The moral of the story...Read the label...it clearly states, "STIR BEFORE USING"

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