Trick for Using Hot Hide Glue

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jread
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Re: Trick for Using Hot Hide Glue

Post by jread »

good timing for me as my kit bridge is going on soon. I used fish glue for the box and haven't started learning HHG. In my case, I got advice from Diane offline and will be going with Titebond (original) for my 1st go. Just posting that to "fish" for more opinions. har har.
JLT
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Re: Trick for Using Hot Hide Glue

Post by JLT »

Yes, I know it's an old thread, but...

I've added one of those infrared non-contact thermometers to my workshop, and have found many uses for it. This might be another one, because you can shine it on the joint and see exactly how warm it is. It might help preventing you from not heating the joint enough, or from heating it too much.

This is the type of thermometer. The URL is for the Harbor Freight one, but I've seen it at other places for about the same price.

https://www.harborfreight.com/121-infra ... 63985.html
jread
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Re: Trick for Using Hot Hide Glue

Post by jread »

I've always wanted an accurate surface thermometer. I think this would be more accurate than the infrared type but haven't really found the need to invest in it. I still use fish glue for gluing the box closed and HHG everywhere else. I've certainly had my share of bridges that don't want to stay on but seem to be doing better these days.


Here's one from Stew:
https://www.stewmac.com/luthier-tools-a ... AYQAvD_BwE
JLT
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Re: Trick for Using Hot Hide Glue

Post by JLT »

jread wrote: Sat Jul 15, 2023 8:39 am I've always wanted an accurate surface thermometer. I think this would be more accurate than the infrared type but haven't really found the need to invest in it. YQAvD_BwE
I have the Stew-Mac one also, and the problem with it is that it takes a while to reach the indicated temperature, by which time the joint has cooled a bit. The laser one, on the other hand, is instantaneous, which is why it's now my go-to tool for this sort of job. And it's about half the price.
banjopicks
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Re: Trick for Using Hot Hide Glue

Post by banjopicks »

Diane Kauffmds wrote: Mon Nov 13, 2017 4:02 pm I love not hide glue, but hate the fast working time. I've had problems closing the box and getting it clamped within the working time. I know that the pieces being glued can be heated, but the the entire rim of the guitar won't stay hot enough for this to work. The glue can be diluted a bit to increase working time (which can affect the strength of the hold), but i still had problems.

I had to "unglue" a couple of pieces, so I used a small hairdryer. It dawned on me that I could heat the already glued pieces, after all of the clamps were in place, to reactivate the glue. So, using the hairdryer, I heated the entire rim of the back/sides.

It worked like a charm. The entire rim is strong.

PicsArt_11-13-02.34.35.jpg
I have used this method a few times and it really does work great. I'm glad to see others doing it as it doesn't get talked about much and it should. This whole thing of heating your shop and racing the clamping is just wrong and unnecessary.
jread
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Re: Trick for Using Hot Hide Glue

Post by jread »

I seem to have far less problems with bridges staying down these days since I've started ensuring my glue is good and hot. I remember being worried about it being too hot (read that glue breaks down or something?) and applied it at the prescribed 130 to 130 degrees F. I'd say about half of the bridges started to lift after a few weeks more more. But ever since I started ensuring that the glue rises to 150 degrees F and pre-warming my bridge and gluing surface with a lamp ( i use infrared lamp but just make sure it's warm to the touch ), I haven't had a single bridge fail. I store the glue in the fridge between uses and have re-used it for several months like this without any new issues. It's only at 150 degrees for a short time before use, I don't let it sit in the boiler for very long. Just heat, use, cool and store.

I shake or stir the glue at 150F and ensure it's all evenly hot. Too hot to touch with your fingers when poured. Very hot.

This thread of course is about rims but I use John's fish glue on the rims to avoid having to rush through that step. I've had no trouble reversing fish glue and it seems to harden as well as HHG.
banjopicks
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Re: Trick for Using Hot Hide Glue

Post by banjopicks »

I don't know where you got those numbers but I have always used 145 degrees F. I'm not sure where I got that number from but it always works.
MaineGeezer
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Re: Trick for Using Hot Hide Glue

Post by MaineGeezer »

I use HHG for bridges and neck sets -- not because it's necessarily the strongest or easiest, but because it's known. 50 years from now when somebody has to do a neck reset on one of my guitars (assuming they're still around then), the person doing it will hope it's HHG, try removing the neck based on that assumption, and not get surprised.

I did have a couple of bridges lift using 192 gran HHG. I switched to 250G, or whatever the next step up from 192G is, and had no more problems. Maybe my HHG gluing technique just got better.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
JLT
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Re: Trick for Using Hot Hide Glue

Post by JLT »

While we're on the subject of hide glue, I'm wondering if I'm doing something wrong...

I cooked up a batch of it as per Frank Ford's web site but instead of refrigerating it, I froze the little packets so I could have just enough to do a build or repair down the road.

A month later, I thawed out one of the packets and used it to glue the braces on the back of a guitar I"m building. I had a little left over, so I stuck it in the refrigerator.

The next day, I thawed out another packet and used it to glue all the flat (un-contoured) braces of the top of the guitar. Again, I had a little left over, and added it to the stuff in the refrigerator.

Tomorrow, I'll glue on the contoured braces (X-brace, etc.) but then I got to wondering if the glue degrades at all with the repeated heating and cooling. I read somewhere that as long as the glue isn't cooked, it should hold up to a few cycles of heating and cooling without ill effect. But I'd like some confirmation of that from somebody who uses it a lot.
jread
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Re: Trick for Using Hot Hide Glue

Post by jread »

I store it in the fridge between uses and have had no issues even after several cycles over a few months. I only mix up about 6oz at once and build a lot so it runs out eventually. I don’t add to used batch though and start with a fresh one when empty. I read that as long as it’s not moldy, it’s fine. Perhaps others have more experience. If I doubt the quality or consistency, I test it on scrap and try to break apart the joint. I tend to be more cautious with bridges and have never had a failure elsewhere. The stuff is hard as a rock when it dries and willingly gives way under heat and moisture when needed to be reversed.
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