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I know this is going to vary depending on Temp of the room, temp of the work pieces, visoscity of the glue, etc. but what's a reasonable amount of time to wait for hide glue to cure? Reading the thread regarding gluing the top to the sides where sometimes a bit of pressure is needed for the top to fit, i am curious how long it takes hide glue to set enough not to worry about the parts springing apart?

For ha-has... i made up a bit of glue last night and glued two pieces of waste mahogany together and tried to see how long it took to set. I played with it a couple of times (say five minutes and 15 min.) but it still was easy to pull apart. I tried it again this a.m. and while it did dry it was still fairly easy to pull apart. I suspect that playing with it before it set caused the glue to not do it's job, and i'll retry tonight. I also may have not mixed it correctly as i mixed it by volume (by eye), and not by weight. I can't tell you the strength of the glue as i don't have it with me. Also, I may have heated it a bit too high as i don't have an adjustable crock pot (i'll go get one ASAP), but still i expected the joint to be a bit stronger than what i saw.

I did make it a bit more watery than i would like, but i'm not certain it wasn't because i warmed it too much, but it was not as thick as a carpenter's white glue.

Thoughts?

Thanks!
Rob

I am currently playing with HHG myself. I do have a submersible thermometer and advise you to get one too.
Yes, it will be more watery than white or fish glue.
I had some samples glued well, some were not good at all.

Did you add fresh hot glue to the parts after pulling apart in 10 minutes?

The glue does set fast, but that doesn't mean you can force the joint in 10 minutes. From what I read, you need to wait 2hours with the clamps on, and then preferably wait a day for full cure before forcing the joint.

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Build log

I've just started using HHG and really like it although it isn't as easy to use as Titebond. It is thinner but after 3 or 4 heat/cool cycles it thickens up some; unfortunately that's about when I throw it out. I'll second the need for a decent thermometer, a small dial meat thermometer that reads 140F is pretty cheap. You can also get a Rival "little Dipper" crock pot for about $15 which holds right at 140F without a thermostat http://www.bedbathandbeyond.com/product.asp?order_num=-1&SKU=12977727.

I mix mine using a cheap digital scale now but the first time I just put some granules in a bottle and added water to just cover them. I let it sit overnight in the fridge before I try to use it although I think it may only need a few hours. My first test blocks I left clamped for 24hr then broke them. Both of them split apart in the wood and not the glue joint.

I use a heat gun to warm up the wood parts before I glue them which allows me more time to move things around.

I clamp overnight and basically wait 18-24hr before stressing the joint. I have no idea if this is the right amount of time but it seems to be working for me.

Good luck!

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Steve Smith
"Music is what feelings sound like"

I have a thermometer but i didn't use it the second test. My first test it went as high as 155 which is why i know i need to get a controllable pot. Even so, i wouldn't think that would have made that much difference.

No, i didn't reapply fresh glue because it was still wet and i thought it would still work. I suspect this was the biggest no-no. Again, i would have thought it would have held somewhat better than it did.

From what i've seen on a couple of tutorials, there's all sorts of preference as far as viscosity goes. I'm going to shoot for something thicker than what i used.

Good luck guys...

Oh, then it's clear: it has to be hot too, not just wet.

155 is high. At that temp you are losing about 10% strength with every hour, so I've read. It's not the end of the world if you overheat a couple minutes now and then, but do it for a longer while and it is toasted.

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Build log

Ideal temp is 140F I get several re-cooks before it is too thick and un-trust worthy. I like mine the consistency of honey or just a tad thicker. It helps to heat the surface of what you are gluing to add a few more seconds in workable time. I do not use it for top and back to rim joints just because I like Fish glue for this joint due to its open time. I love HHG for plate seams, braces and blocks. I use Norland Fish glue for any joint I need to fiddle with to insure alignment. Mike Collins turned me on to Norland Fish glue about a year ago. More open time and the same ease in clean up as HHG. Like HHG Fish glue requires much more clamp time than PVA but is a stronger joint. Fish glue is more susceptible to warm moisture than PVA but how many take a hot shower with their instruments in hand.

Todd I have yet to have a Fish glue joint fail I always leave them clamped up over night and of course do not expose to high humidity or high heat. but I like the stuff and have tested un bathroom shower humidiity on scrap and had no failures.

Rob buddy this toot may be helpful to you - at least I hope so: http://luthiersforum.3element.com/forum/forum_posts.asp?TID=12088

Steve I bought a little dipper to use as a glue pot and mine ran too hot. With two different thermometers it ran in the 155F range which was not a good thing...... I never investigated if it could be taken apart and adjusted which may be possible. But I would double check yours perhaps using a couple thermometers and be sure that it is working substantially as described.

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Ann Arbor Guitars

Thanks for the warning Hesh. I did double check mine and always run it with a thermometer in it. With the lid off and the shop at 65F it runs right at 140F. If I put the lid on it runs too hot. I took mine apart once to see if it can be adjusted and it can't. The only thing in there is the cord, an overtemp shutoff and the heating element. Sorry to hear yours didn't work, I'll be more careful about recommending them in the future.

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Steve Smith
"Music is what feelings sound like"

Thanks for the warning Hesh. I did double check mine and always run it with a thermometer in it. With the lid off and the shop at 65F it runs right at 140F. If I put the lid on it runs too hot. I took mine apart once to see if it can be adjusted and it can't. The only thing in there is the cord, an overtemp shutoff and the heating element. Sorry to hear yours didn't work, I'll be more careful about recommending them in the future.

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Steve Smith
"Music is what feelings sound like"

Steve thanks for that and I am very glad to hear that your's works fine. 140F is perfect!

I might have just had a bad one.

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Ann Arbor Guitars

Michael,

Where do you get the Norland Fish glue? Is it different from other fish glues and if so, how?

I've no experience, but I've read (and seen on Robbie's glue video) that fish glue is about as stiff as hide glue but has the bonus of longer working time plus it doesn't need to be heated. I was thinking of using it on my first build......should I reconsider?

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Formerly known as Adaboy.......

Another addition to your arsenal of hide glue equipmment would be a Salton warming tray (or similar from other manufactures). It was designed to keep food warm at the table or in a buffet setting. I use it to warm up my braces prior to applying the hide glue. If I remember correctly, it gets to the 130-140 degree range. Not too hot to handle the wood, but sufficient to keep heat on the glue spread until well after you have it in place and clamped. That should eliminate any skinning over of the hide glue from cooling and provide for a very well glued joint.
I use is winter, spring, summer and fall.

You can probably find one in a local thrift store for not much $$.

I also used it to warm up lacquer in the spray gun pot when the weather got cold.

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Hank Mauel

Thanks for the replies!

Hesh, yes - I have seen that tutorial. If i missed any part about set times i apologize for reasking the question.

I am surprised at the longer set time for HHG... seems i had somehow gotten the impression that it was much quicker than PVA! My first trial i had only made a small (very small!) amount and set it in an open tub floating in a too hot crock pot. When i tried to pick some up, it had gelled almost imediately and i couldn't get it to spread. UGH! Ovviously it lost moisture very quickly in the open tub and was useless. Now i am using a small squeeze bottle at it works much better to apply. I'll need to play with consitency and heating.

Thanks again.

Rob

norlandprod.com/

Hide is a bit weird. I keep my heater in the 140-145 range and the glue itself ends up being in the 135-140 range (glue in baby food jar, applied with a brush sized appropriately to the job or occasionally poured on and spread with a credit card). It does take a sort of set in a short time.

If glued and clamped right, you can carve braces 45 minutes after you stick them on to the top. When putting veneers on a big batch of necks (they were either 1/32" or 1/16", it's been awhile) I spread the hide on thin, held for 30 seconds against a flat surface, and then set them aside. 50 necks, no peels or lifts, and the veneers were machined through later (headstock shape and slots were cut after gluing them on).

On the other hand, hide dries poorly if the moisture can't get out of the joint. If vacuum clamping, I leave hide under vacuum for at least an hour on small surfaces and two on large ones where I might only clamp for half those times or less if it was open air. If the glue had been too wet, too cold, or there was too much in the joint (either due to a poor fitting joint or insufficient clamping force) then the joints above wouldn't have gelled/dried as quickly and they would have failed. In really poor 'drying' conditions (ie: gluing something completely nonporous to something which doesn't soak up water well) some joints need to be left up to 48 hours to dry, and some need to be heated up to dry at all in those conditions!

If I have the luxury, I will leave stuff clamped under as much pressure as I can for as long as I can. I'll do every piece of other work I can find before taking a glue joint out of clamps.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

FYI to the assembled hide glue aficianados...I just did another back brace glue up with hide glue, using the Salton hot tray to warm the braces. I did test the temp on the hot tray with my digital thermometer and it was 138 degrees. I left the four back braces on there while the Rival soup pot came up to temp and the hide glue reached 140 degrees in that improvised double boiler. Everything worked as usual...no problems...so I decided to test the time it took for the glue to form a skin, which would basically be the "open" time for getting a joint together. Used two scraps of brace stock and warmed them up. An even glue spread took almost 2 minutes to skin over on the sample brace (shop temp was 62 degrees). The wood is a heat sink and, once warmed, it's mass is slow to cool down. That should give anyone adequate time to get the brace in place and clamped. Next I did a test glue up of two pieces of the same brace stock, warmed, glued together and clamped. The joint was solid after two hours, but the squeeze out was still pliable. Left overnight and the squeeze out was now crystaline and the joint would take my twisting and turning with no problem. I did not attempt to reach the "failure" state, but I'm pretty sure the braces would have splintered before the joint failed.
So, from that data, I'd suggest leaving a glue joint over noght and at least two hours under clamp pressure...and longer if you can plan for it.

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Hank Mauel

I bought a Little Dipper and it ran between 155F and 160F with the lid on. I didn't get a lot of time to try and get the temp down because the next day it walked off to a Halloween party filled with cheese.

John, mine also runs too hot with the lid on but runs right at 140F with the lid off. Maybe you can check it again if it ever comes back home.

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Steve Smith
"Music is what feelings sound like"