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I've been doing a lot of reading lately on hot hide glue and its proper use. It seems that there are a lot of different opinions on the handling of HHG. I've been reading stuff from instrument builders, fine woodworkers, and retailers who sell the stuff. I also read through a number of old threads on the forum in regards to HHG and fish glue. I'd like to get some opinions from you who regularly use HHG.

The two question I have are in regards to handling and clamping.

As far as handling goes, how long should you use a batch of glue before you replace it? I've read some sources that say use it for no more than a day and never reheat more than 4 times. I know of other who will keep the same batch going for a week+. I also saw a video clip from a guy who I think did restoration and furniture work. I got the impressions he just kept adding to the same batch of glue as he used it up fairly quickly, if I remember right he also said the idea that you damage the glue by reheating it over and over is a myth. (as a side note, I am well aware that the glue is damaged when heated over 150, and I know many people use the practice of keeping glue cubes in the fridge).

As for clamping, again their seems to be a pretty wide range of opinions. I read of several Violin and Mandolin builders who use a rub joint for jointing their tops. The other extreme says it should be clamped for at least 6 hours. The middle of the road view seems to be 1-3 hours of clamp time.

Any information in regards to these subjects would be helpful, I'll gladly add your input to the mountain of stuff I've already gone through.

Thanks

Josh

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Josh...I mix about 50 grams of crystals at a time at the start of each guitar. I use this within 1-3 months. I fill a 2 oz working squeeze bottle and heat to 140* - 150*F numerous times within that period. I frequently refill the 2 oz bottle from the refrigerated remainder until it's used up or I throw it out at 3 months approx.

My clamping time is 2-4 hours for braces, 6-8 hours for joining plates and 24 hours for bridges. I've removed clamps as soon as 1 hour for certain items where there are no stresses impinging on the joint. I've used HHG for 8 years with no problems...it's extremely consistent and predictable.

Lately I've been gluing plates with Fish Glue and I like the results.

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

I'm planing on using HHG for #2 as it will be interesting to try new glues & methods. My main concern was how long I can keep one pot for before having to throw it away. I can't do many processes in one day due to the lack of clamps and time etc.

Also, I don't want a commercial glue pot (can't justify paying for one) but what is an easy & simple way to heat up and maintain heat of HHG? Someone told me a microwave but that sounds very iffy to me. If I read what JJ said properly, then keeping glue for 3 months or so would be perfect for me.

Josh I have been more careful lately to not keep reheating the same batch of HHG.

"Excess heat or repeated reheating as well as microbial degradation will affect the bond strength by reducing the places where hydrogen bonding can take place."

The above is an excerpt from Hide Glue - Historical & Practical Applications by Stephen A. Shepherd page 11 under Chapter 2 Chemistry and Physics.

The granules keep indefinitely so I am now just mixing small quantities as I need them.

Alan from the Aussie forum posted this some time ago. I found it refreshingly practical.http://woodtreks.com/animal-protein-hide-glues-how-to-make-select-history/1549/

HHG isn't rocket science. I've found NO difference in joint strength when comparing joints made with 3 month old re-heated and refrigerated glue compared to freshly mixed glue. I have a feeling that I'd get similar results at 4+ months as well but some say that mold growth can be a problem. Nonetheless, I have never had a mold problem...I attribute that to boiling my containers prior to filling them with fresh glue. But I still use distilled water instead of tap water. Old chemist habit I suppose.

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

I've been filling two or three little squeeze bottles when I make a batch. I try to plan so I'll use a bottle for several things with one heating like glue braces and join a top or back and/or maybe glue a bridge. They don't get reheated more than 2 or 3 times. I like to glue bridges with a fresh bottle. I've kept them in the fridge a long time. If there's no mold I use them. I have no idea what the right answer is. Something tells me we are over thinking this whole thing.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I couldn't agree more…

I haven't had to throw out any HHG yet, it seems there's always something to glue. I keep it both in small jars and Elmer's bottles, it fits nicely in the Hold-Heet, but put them in the fridge at the end of the day. If it goes bad, I can bet it will smell, and not nicely… In any case things seem to hold together fine, and I don't count how many times I reheat a batch, nor do I care to. It's in the water bath all day long at about 145º…
Re-clamping time: HHG has a fair ammount of water in it that needs to evaporate, so to glue peghead veneers, fretboards, bridges and the like I tend to leave things clamped overnight in order to avoid possible warping.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I've only recently started to use HHG regularly. I've used in on and off for years, mainly in repair work. My HHG setup consists of a coffee mug in a soup pot on a hot plate. I generally turn the heat on when I come into the shop in the morning and leave it on all day (with the exception of a 1hr lunch when I turn it off). I just leave my glue in the pot over night and when I come in the next day turn it on again. I've been using really small batches of glue so that it never goes more than 3-4 days before it is used up. Now that I plan to use it more regularly I'll mix up a batch for the fridge. I've also got a bottle of fish glue on the way and plan to use that for rims and some other parts where the additional working time is helpful.


JJ, thanks for posting that video. I did come across it as I was searching for info. I guess as long as you do the "sticky finger test" and the glue checks out you're okay.

Thanks everyone for the tips.

Josh

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Just to see what would happen, I left a closed bottle of HHG on my bench for months, un refrigerated, and after having been heated several times. I just wanted to see how long it would take it to go bad. After about 4 months it started to mold on the top of the glue in the bottle, and was covered within a couple of weeks after it started.
So, it happens fast when it starts. During the time it was there, I opened and smelled it a number of times, and it never smelled bad, even when it got moldy. It did smell moldy!

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

...one more related question, what strength of glue are you guys using. I can't even rember what mine is, but I think it might be the 192. I noticed that LMI sells 192 and StewMac sells 256 gram strength. What are you guys using?

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

192 gram strength. I buy it directly from Milligan & Higgins in bulk.

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

I have 150, and 260 from Lee Valley when I was there last month. I have 192 from a great vendor on ebay. And I have Knox Gelatin, which is rated at 340, and I found out why.

Bob

While we're on the subject, I've been keeping 2 bottles in the fridge each having a different viscosity. I use the thicker to lay a bead down on the brace outline or on the brace itself and the thinner stuff for general purpose...and I always use that hair dryer to keep the surfaces warm before applying. Anybody else doing this...or other useful methods.

Nice to have a HHG thread that hasn't gotten too controversial...yet!

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

I keep mine in the freezer in 2-4 oz bottles and find I use it all before it goes bad. Never get to 3 months.

I've got a heat lamp which I can position around my go-deck or hang from the ceiling if I'm gluing plates. I've found it is helpful for delaying the gel time of the glue. Another tip I've found with the go-deck is to preload my go pars. If I'm gluing braces, I'll load all the go-bars into the deck and position the ends so they are right next to where the brace will go. Then after applying glue to the brace I can quickly position it and just lift the ends of the go-bars onto the brace. It saves a lot of time and is much easier than trying to load a bunch of go-bars while quickly positioning the brace before the glue jells.

A word of caution if using a heat lamp, I was using it the other day and had it a little to close to my finber-glass go bars. I was bracing a back and got the first brace glued up fine. As I was gluing the second brace I noticed that one of the bars on the first brace was starting to bend. I was in the middle of gluing the second brace and before I could reach the plug for the heat lamp it went. Braces and go bars were flying left and right! I managed to get the bars back on the first brace and after putting some fresh glue on the second brace everything was fine. The only damaged the back received was a bit of a dent in the centre strip, which will be replaced. I usually wear safty glasses when doing work on the go-bar deck but that day I wasn't. I'll be sure to put them on next time...

Josh

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Hi Josh

I also use the IR heat lamps and pre place the gobars next to where the brace will be glued. I have never had a lamp related accident like you described but I did melt the plastic tips on a couple gobar ends with my heat gun when reheating a brace that I felt the glue was jelling too fast before I started the heat lamp thing. I put a couple brace stock scraps held with a gobar in position to to aid quick alignment of the brace I clamp my lamps on the deck top and have got close to the lamps a few times with my head but have not yet been burned though had a couple close calls.

Fred

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

I usually lay my heat blanket out on the counter top and get it to around 150 degrees and set the braces/bridgeplate etc. on it while I'm getting ready to glue. I use a heat gun to warm the top. I know a lot of folks use a food warming plate to preheat the parts. I usually use a hair dryer to heat the bridge footprint area when doing a bridge. I had one bad experience with a heat gun there. If you use one turn it way down around lacquer!
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

One of the advantages to using a hot plate and soup pot to keep the glue warm is that I can put smaller parts like a bridge plate on the hot plate to warm it up. That works well. I've got a number of different sizes of heating blankets so maybe I'll give those a try at some point.

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com