Official Luthiers Forum! :: View topic - RE: Thinning Down Wood Glue

runamuck,
The joint will be slightly weaker than one achieved using the unthinned glue, but
you will still end up with a strong glue joint that will ensure wood shear. The trade
off is the benefit of the ability of the slightly thinned glue to run freely into a crack
for repair.

I've used thinned aliphatic resin glues for repairs since the early 70s and have never
had a joint fail to hold up. I've probably repaired more than 100 headstock cracks and
breaks that have held up well under string tension since and all with thinned aliphatic
resin glues.

You'd be surprised how strong a joint will be even if the glue is thinned to
50% with water eve though I never go that thin with it. There are lots of credible sources
for information around.

Regards,
Kevin Gallagher/Omega Guitars

Author:	meddlingfool [ Mon Sep 21, 2009 7:11 pm ]
Post subject:	RE: Thinning Down Wood Glue
Does watering down wood glue to make it runnier make it less effective, or does it just increase the drying time? My thinking would be that it's the solids that do the work, so as long as the water has sufficient time to draw away, what's left ought to be good glue just as strong. Can anyone confirm or destroy this thinking? Thanks

Author:	Kevin Gallagher [ Mon Sep 21, 2009 8:06 pm ]
Post subject:	Re: RE: Thinning Down Wood Glue
Thinning the resin glues that are common to guitars building is perfectly acceptable in the proper applications. I do it often in repair work, but never in my building. The lower viscosity of the thinned glue allows it run deeper and more freely into cracks and gaps that are involved in a repair scenario so it is a valuable characteristic to have in your glue when necessary in situations when it will help. A crack, loose brace or other repair that needs to be opened in order to insert or inject or drip glue into the trouble area limits the space in which you have to get a spatula or tool to carry the glue so there are many times that allowing it to run in is the only option and the thinner glue works great in those instances. The glue doesn't loose it adhesive value or ability, but it does take a bit longer to dry fully and achieve the best joint between the pieces being glued together. Regards, Kevin Gallagher/Omega Guitars

Author:	runamuck [ Mon Sep 21, 2009 9:03 pm ]
Post subject:	Re: RE: Thinning Down Wood Glue
Kevin Gallagher wrote: The glue doesn't loose it adhesive value or ability, but it does take a bit longer to dry fully and achieve the best joint between the pieces being glued together. Regards, Kevin Gallagher/Omega Guitars That's not what I was told by a Titebond rep.:thinning aliphatic resin more than just a couple percent weakens the joint. He couldn't say how much. I've never tested it myself so this is second hand knowledge on my part. But the source is credible.

Author:	meddlingfool [ Tue Sep 22, 2009 12:29 am ]
Post subject:	Re: RE: Thinning Down Wood Glue
thanks folks what I need it for is a headstock fracture that is open but barely, so I figure thinning some Lee Valley brown glue so it runs to the bottom ought to do the trick, I'll just leave it clamped longer than normal.

Author:	Kevin Gallagher [ Tue Sep 22, 2009 12:36 am ]
Post subject:	Re: RE: Thinning Down Wood Glue
runamuck, The joint will be slightly weaker than one achieved using the unthinned glue, but you will still end up with a strong glue joint that will ensure wood shear. The trade off is the benefit of the ability of the slightly thinned glue to run freely into a crack for repair. I've used thinned aliphatic resin glues for repairs since the early 70s and have never had a joint fail to hold up. I've probably repaired more than 100 headstock cracks and breaks that have held up well under string tension since and all with thinned aliphatic resin glues. You'd be surprised how strong a joint will be even if the glue is thinned to 50% with water eve though I never go that thin with it. There are lots of credible sources for information around. Regards, Kevin Gallagher/Omega Guitars

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RE: Thinning Down Wood Glue http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=23875	Page 1 of 1

Author:	runamuck [ Tue Sep 22, 2009 9:38 am ]
Post subject:	Re: RE: Thinning Down Wood Glue
Kevin Gallagher wrote: runamuck, The joint will be slightly weaker than one achieved using the unthinned glue, but you will still end up with a strong glue joint that will ensure wood shear. The trade off is the benefit of the ability of the slightly thinned glue to run freely into a crack for repair. I've used thinned aliphatic resin glues for repairs since the early 70s and have never had a joint fail to hold up. I've probably repaired more than 100 headstock cracks and breaks that have held up well under string tension since and all with thinned aliphatic resin glues. You'd be surprised how strong a joint will be even if the glue is thinned to 50% with water eve though I never go that thin with it. There are lots of credible sources for information around. Regards, Kevin Gallagher/Omega Guitars Thanks for that Kevin. Jim

Author:	george wilson [ Tue Sep 22, 2009 9:45 am ]
Post subject:	Re: RE: Thinning Down Wood Glue
Sit a bottle of liquid hide glue in a pot of hot water,and perhaps change the hot water for new hot water till the glue bottle gets good and warm. The hide glue will be quite thin,and will flow anywhere. It is not thinned out,just a LOT thinner when warm. It is easy to wipe up the excess,too.

Author:	Dave Livermore [ Tue Sep 22, 2009 7:29 pm ]
Post subject:	Re: RE: Thinning Down Wood Glue
If you're going to try thinning it down and want to know what the effects are, test it. Thin some glue and stick a couple boards together. Do the same with unthinned glue. Then let us know what the results were like when you tried to pry them apart a day or two later. I'd love to hear about it, and you'll be happy to have the knowlege and experience under your belt before you try getting that crack back together. Dave

Author:	keys1 [ Thu Sep 24, 2009 3:33 pm ]
Post subject:	Re: RE: Thinning Down Wood Glue
Funny you all are talking about thinning glue down. I broke a double handle wood screw clamp and used white guitar glue on it, that did not work at all, it broke again. I got some Tight Bond II that is for indoor/out door use. I red everything on the bottle then called and asked the rep if the glue would work as well thinned a bit and explained what I was doing. He said I should not but did not say why, so I asked to speak to the techs or chemists. He came back and stated that thinning could thin the different resins enough so they would not hold as well. I asked what to do if I needed to get glue into tiny places? He stated to use epoxy. I know you wouldn't normally use epoxy on a guitar but at the same time I am all for experimenting big time like some one else mentioned. With the pieces of wood and thin the glue down and see if it holds. I'm trying it.

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