hide glue, fish glue.. working time.

[PlaneSimple]

So I am getting close to gluing f5 soundboard to rib.
I have used hide glue thus far for rib and blocks. I suppose I am in research phase before I proceed.
I am curious how others glue plates to rib, as the working time is short. I AM using 192 g/strength glue.. however.
I see videos on yt of violin makers inserting a hot pallette knife to re-energize the hide glue. Do you do the same? I am also considering adding assistants for this part of the operation.. as in, ready?set.glue!clamp!
What is your experience? Are you able to glue up a plate by yourself, working quickly?
Does any of you use fish glue?
Thank you.

[ProfChris]

I use hot hide glue for my ukuleles. Because gentle heating keeps the glue workable I simply heat the plate with a hair dryer, clamp up, then heat again and tighten clamps.

If I don't get a perfect glue line at any spot I can re-heat that spot, introduce a little more glue (slightly thinned - you can usually see the glue start to bubble in the bad spot and just dab on some more glue and let it seep in) and re-clamp. Job done.

[Cush]

For a speedy and accurate way to glue up the plates I use a pair of alignment pins made from small dia. wood dowels. I drill just a very shallow hole to accept the dowel. I started doing this on archtop guitars and I liked it so well that I now do my mandolins this way also. It takes a some time to install the pins but they pay off at glue up time. Once the plate is positioned clamping is a quick process with no worries. So far I have never had any problems but don't drill to deep or they will show. Some folks glue a temporary block outside the rim for the pins but that is one extra step so I have not tried it.

[sunburst]

I use hide glue to glue plates to rims, including guitars, which obviously take a little longer than mandolins. I warm the parts, sometimes warm the room, and work under a heat lamp to keep things warm while clamping.
I use a go-bar deck, and I simply put a heat lamp bulb (one of those big, 500 watt, red bulbs, like the ones in bathroom ceilings) in a swing arm lamp (like an architects lamp) so that I can shine it on the work in progress. That gives me enough working time as long as nothing goes wrong. I don't have to hurry, but I do have to work quickly. If something happens to slow me down and it looks like I'm not going to finish before the glue starts to jell, I have no problem with cleaning the glue off and starting the process over.

BTW, my alignment dowels are pieces of round wooden tooth picks.

[David Houchens]

I clamp up everything dry. Then remove a few clamps and glue that section, then re-clamp. Then repeat. I start with the neck block and tail block, the do the sides. No rushing. I do use a heat lamp to keep things warm while I'm at it.

[j. condino]

David: Is that the neck glued on before you bind the top???

I used fish glue for a couple of instruments- very easy to work with, but it is also very sensitive to water and moisture, so it can fail much easier. After a couple of obvious fish glue fingerboard failures on necks that had the finish removed, I stopped using it.

I glue the entire top on an upright bass using hot hide glue in one session almost every week of the year. Do youuse a steam gun or hair dryer to warm up the surface first? Often I see people who are struggling with hot hide glue early on putting nice hot glue on cold parts that cause it to jell very fast. Like most of the things we do, practice, practice, practice.

J.
Condino.com

[PlaneSimple]

Great responses all, thank you !
Yes, fish glue sounded interesting for working time, however, the water/sweat (non)resistance issue scares me away from bothering with it.

[RonEllison]

I got some advice from the frets.net forum which relied on the hot hide glue characteristic of being able to be reactivated after it has dried. You paint glue on the lining or kerfing and the blocks, and also on the front or back. You let these dry separately. After the glue has dried, an hour or so perhaps, you get a couple of thin pallet type knives in a pan of boiling water. Instead of using alignment pins (I will next time) I clamped the front to the end block, dry glue against dry glue, took one of the knives out of the boiling water and reactivated the glue at the neck block and clamped that up and replaced the knife in the hot water. With the front correctly aligned I released the clamps at the end block. Then I reactivated one spool clamp's width next to the head block and clamped that. I did the same on the other side. Gluing and clamping a bit at a time, from one side to the other, I worked my way down to the end block. No drama, no fuss and no rush. All I heated was the pallet knives.

It's interesting to read all the different methods that others have described. I'll definitely try the locating pins in future.

[RonEllison]

I've just seen the dates of the other posts. I guess the job's been done by now. How did it go?

[Wes Brandt]

I got some advice from the frets.net forum which relied on the hot hide glue characteristic of being able to be reactivated after it has dried. You paint glue on the lining or kerfing and the blocks, and also on the front or back. You let these dry separately. After the glue has dried, an hour or so perhaps, you get a couple of thin pallet type knives in a pan of boiling water. Instead of using alignment pins (I will next time) I clamped the front to the end block, dry glue against dry glue, took one of the knives out of the boiling water and reactivated the glue at the neck block and clamped that up and replaced the knife in the hot water. With the front correctly aligned I released the clamps at the end block. Then I reactivated one spool clamp's width next to the head block and clamped that. I did the same on the other side. Gluing and clamping a bit at a time, from one side to the other, I worked my way down to the end block. No drama, no fuss and no rush. All I heated was the pallet knives.

It's interesting to read all the different methods that others have described. I'll definitely try the locating pins in future.

You can do the same thing but using the glue, med/thin, itself ...I've been using this method for viols for a long time and I think it is typical in the violin world… more like 3 or 4 spool clamps at a time for me and alternating sides from the tail ending up at the neck block. But doing it dry is an interesting angle.

Another possibility is to add urea to the glue to slow down gelling… any one doing this? ...if you do a Google it's quite common and there are recommendations up to 15% by dry weight… I use 10% and it slows it down considerably… given the right room temperature …it's no problem gluing up mandolin plates in one shot especially if you use pins and have done a dry run.

Urea is at least a large part of what is used to liquid hide glues.

[sunburst]

Another possibility is to add urea to the glue to slow down gelling… any one doing this?

I've added urea a few times when re-gluing the backs of guitars that had to be opened for repair. Alignment can be tedious in that situation, and a little extra working time can be a help. As I understand it, urea, freshly added, does not affect strength of the joint up to about 10% by weight. I add a little urea to the already-dissolved glue right before gluing the joint, then discard the glue after the job is done because I understand that the urea degrades the liquid glue over time. I'm only operating on what I've read and been told, and I don't know for sure that urea degrades the glue, but it's a chance I prefer not to take, considering the price of hide glue.
(I've also read that using urine instead of water to dissolve the glue was the traditional method of adding urea to glue. Apparently, human urine has about 9.3 g/L urea, so from that, I suppose we could do the math to figure out the percentage by weight, but it's not that important to me! I'll stick with using store-bought urea if I want to slow down my glue.)

[Wes Brandt]

Yes…I've read that historically that urine was what was used… no problem finding a source for it ...though I wonder how long before it fermented. Probably not that long.

I do notice the made up glue gets moldy faster if I don't refrigerate…

I also read that an historical source for yellow pigment was to keep peeing in a container over time ...that would quickly evaporate. What was left was …yellow.

[RonEllison]

That's all a wee bit too detailed for me.

[Cush]

If you add some liquid hide glue to hot hide glue it will extend the open time of the hot hide glue. It is almost the same as adding urea as that is what keeps the liquid hide glue liquid in the bottle. I did a few tests and just a little does the trick.

[sliebers]

Anyone recommend a good source to buy urea? I probably shouldn't admit this, but I used my own urine instead of water to mix HHG on my first mandolin. The mandolin is about 14 years old and it's still going strong. It extended the open time of the HHG enough to get everything clamped up without heating any parts.
Now I use water to mix and heat parts before and during clamp up with an electronics heat shrink gun.
I have also used fish glue for guitar bridges with no problems. It does take forever to dry. I leave things clamped up for a minimum of 12 hours when using fish glue.

[sunburst]

Urea is used as a mordant for dyes. Look for tie dye supplies. Perhaps Hobby Lobby, Michael's,...

[Wes Brandt]

This may sound a little funny but... Dick Blick art supplies is where I got mine…

http://www.dickblick.com/products/ja...fabric-dyeing/

The idea of adding liquid hide glue is interesting.

[sliebers]

Thanks John and Wes. I would have never thought to look in a hobby or art supply store.

Scott

[Bernie Daniel]

I've added urea a few times when re-gluing the backs of guitars that had to be opened for repair. Alignment can be tedious in that situation, and a little extra working time can be a help. As I understand it, urea, freshly added, does not affect strength of the joint up to about 10% by weight. I add a little urea to the already-dissolved glue right before gluing the joint, then discard the glue after the job is done because I understand that the urea degrades the liquid glue over time. I'm only operating on what I've read and been told, and I don't know for sure that urea degrades the glue, but it's a chance I prefer not to take, considering the price of hide glue.
(I've also read that using urine instead of water to dissolve the glue was the traditional method of adding urea to glue. Apparently, human urine has about 9.3 g/L urea, so from that, I suppose we could do the math to figure out the percentage by weight, but it's not that important to me! I'll stick with using store-bought urea if I want to slow down my glue.)

By adding urea to hot hide glue (HHG) one is essentially making fresh liquid hide glue. Since it seems to be concerns about LHG shelf life that are the source of most of the objection for using it this would eliminate that issue.

If there are no serious concerns about urea weakening the bond strength of HHG I could see that routinely adding urea to your pot might be a handy thing to do as it would make any gluing operations less time sensitive?

I took the time to look into LHG shelf life some time ago and found the the two major commercial suppliers of LHG both have a one-year shelf lives listed on their product. So that is something to check out before you buy it.

I have read that there is a good test that you can use on LHG if you are uncertain about its condition. Squeeze a small bead of the glue on the bench top overnight -- if it turns in to a clear, amber, crystalline ball that shatters under a hammer the glue is still good.

[sunburst]

By adding urea to hot hide glue (HHG) one is essentially making fresh liquid hide glue. Since it seems to be concerns about LHG shelf life that are the source of most of the objection for using it this would eliminate that issue.

If there are no serious concerns about urea weakening the bond strength of HHG I could see that routinely adding urea to your pot might be a handy thing to do as it would make any gluing operations less time sensitive?

First of all, The hide glue that I've added urea to has jelled in the glue pot when cool very nearly like pure hide glue, so that would indicate that I'm not adding nearly as much urea as the makers of liquid hide glue add, and if there is anything else they add, I'm not adding that at all, so I don't consider the glue I've added urea to to be equivalent to LHG, fresh or otherwise.

The main drawback of LHG, from what I've been able to gather but not confirm, is that is tends to be more hygroscopic than pure HHG, and that joints are more likely to fail in high humidity. If that's true, it is an incentive to me to avoid LHG, and to avoid routinely adding urea to my HHG. I find the working time to be adequate with HHG as long as I prepare properly and work quickly and efficiently, so extended open time is only an advantage occasionally.
Since I don't fully understand the chemistry of and/or the mechanism by which urea slows down the gel time of HHG, I like to er on the side of caution. I've been told that some kind of reaction happens, with time, in the hot glue, or gelled glue that is still in the pot, that changes the glue and makes it less affective. If that is true, I prefer to avoid the situation, so I treat HHG/urea mix as though it is a ticking time bomb, and consider each small mixed batch to be for a single use.

[Bernie Daniel]

First of all, The hide glue that I've added urea to has jelled in the glue pot when cool very nearly like pure hide glue, so that would indicate that I'm not adding nearly as much urea as the makers of liquid hide glue add, and if there is anything else they add, I'm not adding that at all, so I don't consider the glue I've added urea to to be equivalent to LHG, fresh or otherwise.

The main drawback of LHG, from what I've been able to gather but not confirm, is that is tends to be more hygroscopic than pure HHG, and that joints are more likely to fail in high humidity. If that's true, it is an incentive to me to avoid LHG, and to avoid routinely adding urea to my HHG. I find the working time to be adequate with HHG as long as I prepare properly and work quickly and efficiently, so extended open time is only an advantage occasionally.
Since I don't fully understand the chemistry of and/or the mechanism by which urea slows down the gel time of HHG, I like to er on the side of caution. I've been told that some kind of reaction happens, with time, in the hot glue, or gelled glue that is still in the pot, that changes the glue and makes it less affective. If that is true, I prefer to avoid the situation, so I treat HHG/urea mix as though it is a ticking time bomb, and consider each small mixed batch to be for a single use.

Thanks for the information. I am going to do some research on the role of urea from a chemistry perspective.

Meanwhile, a few minutes ago I came across this blog on Titebond LHG. The presentation is interesting and has some ideas that I do not recall being expressed on this site before.

But more interesting to me were the comments from other builders and furniture makers including one guy from the Gold Coast, Queensland Australia (a very humid place) and his adventures with hide glues.

[sunburst]

Meanwhile, a few minutes ago I came across this blog on Titebond LHG. The presentation is interesting and has some ideas that I do not recall being expressed on this site before.

I felt a rant coming on as soon as I came to this part, in the comments section of the blog:

"Instrument makers like animal glues also for its brittle hardness as this transmits vibrations from one component to another more affectively [sic] than a rubbery glue such as pva dose."

I'm so tired of that!! Where's his evidence? A good glue joint is very thin, no more than a few glue molecules thick, ideally. How can a few molecules of one substance "transmits vibrations from one component to another" any better than a few molecules of another? Furthermore, there just isn't a whole lot of vibration being transmitted from one component to another in an instrument anyway. We're mostly dealing with standing waves and normal modes of motion, not so much waves of sound traveling through the components of an instrument, crossing glue joints.
Set up a double blind test with expert players and listeners and show me results indicating that a significant majority of those experts actually can tell which guitars/mandolins/whatevers are made with HHG and which are made with PVA, and then I'll believe there is a sonic difference in what those few molecules of glue sound like in a finished instrument! If, on the other hand, results are similar to the expert violinists and listeners who couldn't tell a Stradivari violin from a new violin, I'll continue to believe there is no significant difference in sound between well made instruments with good glue joints regardless of what glue is used.
OK, rant over (or at least laid to rest).

Then there's this:

"PVA on the other hand boasts that the glue is stronger than the wood and the wood always seems to split and not the glue."

Yes, we hear that boast all the time from glue manufacturers, but they don't give you a temperature range. All we have to do is heat a PVA joint and the adhesive becomes much less strong than the wood itself. Taking apart a guitar made with PVA is no problem.


This all may seem strange, coming from someone like me, someone who uses and recommends HHG for most joints in instrument work, but I like it much better when the arguments in favor of HHG are correct arguments.

[Bernie Daniel]

I wondered about those very statements as well!

Of course the problem is that most testing is done at or under ideal conditions whereas in the real world those conditions are most likely not be what is always found. A laboratory is generally kept at "room temperature" but the inside of your car in the summer or winter sure isn't.

Likewise, on the rumors of glue characteristics -- specifically those that lack proof.

Like you note, these probably originate as much from wood workers themselves as from the glue manufactures? For example (not to pick on Gibson) has anyone ever done a double-blind test to prove that using HHG in the master models produces a better tone (yes there are other differences the species of spruce and the finish)?

I think it is true that one generally wants to be able to non-destructively disassemble most wood instruments -- I'll go out on a limb and say that more or less the opposite is true for furniture makers? Maybe not always.

I'm getting ready to take apart and re-glue a walnut rocking chair that I made when number one son was born and pass the re-glued chair on. Back in 1982 I used Franklin hide glue for the joints even though the chair kit was supplied with some kind of dry powdered (casein-based?)glue -- or maybe a white glue?. But I used hide glue because by then I knew some instrument repair guys and they all told me hide glue was the best for wood. I'm not sure I even knew that there was more than one kind of hide glue. To do the reassemble I'm going to use Titebond III -- naturally. One never wants a chair joint to fail!

Meanwhile I have found several more wood working blogs that talk about glues. All of them have the same kind of statements about strongly-held beliefs in glue capabilities with no science-based proof offered.

One thing about LHG in addition to urea, plain table salt (sodium chloride) is also used to increase the working time so I am thinking the chemistry explaination as to why the LHG sets up more slowly than HHG is not going to be very exciting.

[sunburst]

...For example (not to pick on Gibson) has anyone ever done a double-blind test to prove that using HHG in the master models produces a better tone (yes there are other differences the species of spruce and the finish)?

Of course not.
I've been using red spruce for mandolin tops since 1990 or so. Probably one of the first makers of mandolins to start using red spruce this time around. (Red spruce was simply not available commercially until Ted Davis started it's resurgence about that time.) I started using HHG before I started making mandolins, back when I rebuilt a 1927 player piano in my 20s. So, I've been using red spruce and hide glue longer than most makers, and I've never charged extra for it because I never saw a reason to. Suddenly, companies started using the materials I've been using for years (wood and glue), claiming it sounds better, and charging extra!
(I do charge extra for varnish, but that is because of the extra work, not because I can claim that it sound better, I cannot. I don't know the "special sauce" secret varnish that Gibson used (uses?) for the MMs, but I've used at least 3 different varnishes and associated finish schedules and I can't assign any difference in sound to them or to lacquer, so I suspect I would hear no difference if I had the "secret sauce" varnish.)
Tell me why it sounds better if you want me to pay extra for it, and show me evidence to confirm that it sounds better. Not anecdotes, hard evidence.

Sorry for the further rant, but I get really tired of it all sometimes.

[Bernie Daniel]

Of course not.
I've been using red spruce for mandolin tops since 1990 or so. Probably one of the first makers of mandolins to start using red spruce this time around. (Red spruce was simply not available commercially until Ted Davis started it's resurgence about that time.) I started using HHG before I started making mandolins, back when I rebuilt a 1927 player piano in my 20s. So, I've been using red spruce and hide glue longer than most makers, and I've never charged extra for it because I never saw a reason to. Suddenly, companies started using the materials I've been using for years (wood and glue), claiming it sounds better, and charging extra!
(I do charge extra for varnish, but that is because of the extra work, not because I can claim that it sound better, I cannot. I don't know the "special sauce" secret varnish that Gibson used (uses?) for the MMs, but I've used at least 3 different varnishes and associated finish schedules and I can't assign any difference in sound to them or to lacquer, so I suspect I would hear no difference if I had the "secret sauce" varnish.)
Tell me why it sounds better if you want me to pay extra for it, and show me evidence to confirm that it sounds better. Not anecdotes, hard evidence.

Sorry for the further rant, but I get really tired of it all sometimes.

I agree. I've always thought that the "charm" of the Gibson "master model" series, the new ones with the "V" designation, was that they were more faithful copies of their 1920's Loar-signed models than anything else. Personally I would actually pay something for that, but not 2-3 fold for it, so I'll keep my humble Sam Bush model.

Back to glues. I imagine many have seen this but here is a Woodworking magazine article from 2011 on LHG that discusses the ease of use and bonding differences in the most popular Titebond and Old Brown formulations. Titebond adds a lot more to their stew than Old Brown -- for better or worse.
They even compare how the two glues smell! More significant they also found some differences in the viscosity, bonding properties and release characteristics of the two glues -- but the differences were relatively small IMO

The also discuss the idea you raised at adding and ingredient to slow down the gelling process in HHG -- they use salt instead of urea though.

Interesting article. However I imagine many may have already seen it?