Hot Hide Glue

[Bob Gleason]

I'm about 650 instruments into building at this point, about 2/3 ukes and 1/3 guitars, and still puzzle over the visible Titebond glue creep, or swelling, or whatever it is  on the top and or back joints. Although I don't get to see many of my instruments again once they leave my shop, I think that glue creep shows up fairly soon on some of them. It makes a visible , but not tactile noticeable, unevenness of the joint. I've always used Titebond for all joints. I have no problem with how it works on any other joint besides the top and back. Recently I was reading Romanillos's latest book , with whom I studied with 15 years ago and greatly respect. On page 34 of Making the Spanish Guitar he says that he has seen the the same thing and that he finds it" aesthetically unpleasing". Those are my sentiments exactly. I have never witnessed a glue failure on those joints using Titebond, and I trust it, but the look basically sucks! I have hesitated to try other glues, precisely being concerned about glue failure in the high heat and humidity conditions that I live in in Hawaii. My shop is dehumidified day and night, but the instruments can be subjected to a wide range of climates once they leave my shop. Actually very few of them stay here in Hawaii, but still I'm concerned about humidity elsewhere. I don't really see any other glues that I might want to try other than hot hide glue. Because I'm only considering using it on a couple of joints, I can't see having a $100.00+ glue pot sitting on my bench unless I'm pretty sure it is the answer to my problem. On the web I find scientific test results that indicate hot hide glue actually resists heat better than Titebond. That's good. However, probably just because I've used Titebond for over 40 years I'm still resistant to change. I am also wondering why I don't see more of the glue creep problem in factory made instruments. I've got finely planed glue surfaces and tight fits, so that can't be the problem, Anyway, I'm interested in responses that relate to the use of hot hide glue on the top and back joints. Thanks, Bob

[Howard Klepper]

Titebond Original Extend dries harder and has a lot better heat resistance than regular Original.

[Doc Rathwell]

Coming from the violin world, I strictly use HHG for its many know benefits, including resistance to creep compared to aliphatic resins and the clear glue line also compared to aliphatic(s). They come in different bloom strengths, which is essentially a test in its gelatinous state as to force required to puncture it's form. The higher the bloom strength, the stronger the bond and shorter the working time.

Lee Valley Tools has recently released a small glue pot and heater which is well under the $100 mark or even preparation on something like a stove top or burner is possible.

Frank has done a very good test located somewhere in the Frets.com pages comparing the effects of heat on aliphatic compared to HHG which demonstrates very well HHG's superiority in this regard. It takes a bit of time getting used to preparing it but it ain't rocket science.

Best wishes,

Doc

[Christopher Parker]

Thanks for mentioning the Lee valley glue pot. Never knew about that one. And it's cheap! 

[Christopher Parker]

I should qualify my remarks by saying that most of my experience is from doing repair work. I've been in the business since the early 90's, and like you, I have used Tittebond almost exclusively for the majority of the repairs that I've done in that time, and  AFAIK I've had no problems with creeping bridges or neck joints. I can't comment regarding top and back joints. IMO Titebond  is amazingly strong. That said, over the last couple of years, I've been experimenting with HHG, and I find to be every bit as stron (or stronger). I like it for bridges, because of its heat resistance and its resistance to creeping, even though I have no evidence that any of my repairs have ever crept.  I like it for neck joints, because titebond has a tendency at times to seize before the joint is completely closed. IME HHG is more forgiving in that regard. 

I have had decent results with HHG in a jar submerged in water in a crock pot. It's a little tricky to control the temperature, but a small candy or coffee thermometer works well for monitoring temperature. Leave the lid on the crock pot while it's heating up. It's not ideal, but it's worked well for me. Now I'm ready to invest in a glue pot. 

It seems that the trickiest aspect of building with HHG would be that it would be difficult to apply glue and clamp up a top or back within the short working time that one is restricted to when using HHG. I would love to hear how some of the builders here deal with that issue. 

 

[Doc Rathwell]

Hi Christopher,

   Heating the joints and a proper mixture of the water (distilled) & granular (or pearl...although pearl is a lower bloom not suitable for load bearing, shearing or pull force bonds) hide (the HHG should also be fresh and HOT) should allow for ample clamping time as long as dry runs are done first. With heating the joint areas, 3mins or more should be easily achievable, which should be plenty of time. Of course, a perfectly mated gluing surface is essential; HHG is not happy with gaps. In the violin world, "rubbed" glue joints are common for some makers and restorers; this is a process where plate joining is achieved simply by rubbing the plates together on the join with HHG and leaving it; no clamping necessary. The HHG will pull the joint tight as it cools.

Best wishes,

Doc

[LARRY KLOSE]

I visited Bill Bussmann, mandolin builder in New Mexico, several years ago.  We were in his shop and he was joining tops for mandolins.  His procedure was simple: put one half vertically in a vise, warm the joined surfaces with a heat gun, apply HHG, set the second half on top (no clamps), talk about whatever for about 10 minutes and remove the joined, now solid, top from the vise.  Repeat.  As Doc says, the joints pulled tight as they cooled.  Bill does have a home made joiner made from an old Stanley plane that does a great job of putting a very accurate edge on the joint edges of the tops (and presumably, backs).  Gaps are the enemy.

BTW, something to try for using HHG on repairs: a miniature heat gun used by scrap-bookers for heating their stuff.  Looks like it would do a good job on small areas involved in repairs without over heating.  I haven't tried it because the one I ordered from Amazon for about $10 was out of stock and I didn't follow up. 

I first ran across it on an electronic forum where some of the members used it for setting heat-shrink tubing on soldered wire joints.

Larry

[Andrew]

Ive noticed this effect as well, building electric guitars where the glue joints have a whole lot of surface area. I think it has more to do with swelling and contraction than creep. I say this because the effect is always most noticeable where two different wood types are joined (i.e. Where the body wings of a neck through guitar are attached to the body area of the neck laminations) and is usually minimal between similar pieces of wood. With the amount of surface area available, knowing how I prepared/glued/clamped the mating surfaces, and the fact that these joints are under very little stress, I just can't see it being any kind of creep or slippage. I have also wondered if my nitro was attacking the joint a little bit, but then it didnt show up in other items Ive sprayed where it probably should have if this was the case. So Im pretty sure it is most likely to do with the water based titebond, the way it penetrates different woods, and the way two pieces of wood change in the joint region as the moisture content equalizes. Thats my non sciency opinion. In short, Im just as puzzled as Bob by this, and would also like to know how manufacturers resolve this - especially since Im not about to use hide glue on many joints with electrics (maybe fingerboards) despite that Im getting pretty good with it doing repairs with acoustic bridges, broken headstocks and such. Im hoping Mr Vance pipes in here.

Regarding glue pots for hide glue, I personally am glad I got the dedicated electric glue pot. Yes it was a bit pricey, but some tools are pricey. It keeps the temperature right on the mark and lets you focus on putting the joint together. It just works, no screwing around.

[Bob Gleason]

Thanks for all the replies on this so far. Andrew, I'm just using the term creep for lack of anything else to use. I also don't intend to use HHG on other joints on the guitar, but those large flat glossy surfaces of the top and back really bother me when they are broken up by the visible line. I don't think it shows as much in other places because it is probably largely visible due to refraction differences of some kind. If HHG will stop this phenom on the top and back, I would be willing to go there. What kind of glue pot did you get? I've read a lot on this topic, and so many people think that accurate temp control is very important, so I think I'd go in that direction just to be on the safe side. If the use of HHG will fix this, I would be a very happy camper. This has plagued me for many, many years!

[Doc Rathwell]

Hi Bob,

   Creep is the correct term. I imagine you are joining same species woods...for the soundboard anyways and more often than not the back as well. We are discussing acoustic instruments, correct? Even manufacturers of aliphatic warn of this movement in their bonds. The only other options are a poor joint in the first place, unproperly dried/seasoned woods or humidity issues. 

   The HHG pot from Lee Valley will suffice fine but if you want to spend more money, Stew Mac sells the Hold-Heet, which is essentially the same thing (a single temp heater designed to maintain a roughly 150° temp ) but bulkier and maybe 6 time the price. I tossed that for the Herdim, which has a temperature control, slightly smaller than the Hold-Heet and about 10 times the price of the Lee Valley. It's available from Howard Core. I now use the Lee Valley for work from my home because of its small size and the fact it works perfectly fine. It's not hard to understand how to judge the glue as its in its prepared state; recall that this was done for hundreds of years, at times by candle light by makes of bowed and plucked instruments before electricity with the glue warmed by flame...

Best wishes,

Doc

[Bob Gleason]

Doc

Yes, we're talking acoustic instruments on my part anyway. Again, I don't consider Titebond to be a structural problem at all. It's just the visual that I want to avoid. I guess I'll just have to try the HHG. I have asked a lot of folks and tried the web a few times, but nobody ever says that they specifically had the same problem with Titebond and then solved it by switching to HHG. So, you are saying the Lee Valley one will work fine, and the extra ability to do temp control is not needed right? With that one would you get the glue up to 140 degrees with a double boiler and then put it in the Lee Valley unit, or will the Lee Valley unit get up to that temp on it's own? Thanks again for the info.--Bob

[Doc Rathwell]

Hi Bob,

   The temp control isn't necessary. My guess is the Hold-Heet (which is just a plug in and go double boiler like the LV one) is likely more in use than the temp controlled offerings as its been around longer. I got the Herdim because I wanted to try it and my Hold-Heet I got second hand in quite a messy state. It still worked but I just wanted to spend money I guess. And again, before that, this was all done with flame. In fact, Herdim makes a flame double boiler that I've been after for a while but it's not available in North America any longer. But I'll get it some day. Piano technicians have something similar I understand.

   The Lee Valley one will get there in time, but the recommended process for it is to add boiling water to both the inner and outer pots to warm them. Then remove the water from the inner pot and add the prepared HHG. Remove the boiled water from the outer pot and add another supply of boiled water. At this point, they considers 2-3mins for the HHG to come to a workable temperature and stay this way for roughly 20mins. This is without using the warmer, which will maintain the heat for some time longer. Always best to have a thermometer on hand if you're worried about the temp...I actually don't know of any glue pot that indicates the temp of the glue itself...or the outer boiler pot for that matter.

Best wishes,

Doc

[Andrew]

Bob, I use the Hold Heet that Doc describes. He has some other suggestions too that are worth considering for sure. I got the Hold Heet from Stew Mac because that was convenient for me and have been happy enough with it that I never bothered to see what else there is.

I did consider that you would be joining two similar woods. They're also much thinner than what I work with usually and probably subject to more stress, so creep could likely be more of a factor for your situation, as well as swelling and contraction from the introduction of moisture via water based glue. Thinner pieces of wood react more drastically to this than thick ones obviously. Hopefully the totally rigid state of hide glue resolves this issue for you.