Would love to discuss the using of hide glue...

[jamie shard]

I've used hot hide glue on a few projects. I feel like I need to rush and soak the joints, then clean up the mess afterwords. As others have said, the fact that it doesn't seal off finishes is really great and necessary for my remedial hide glue skills.

I would be very interested in folks describing how they have used hot hide glue for carcass dovetails. For smaller glue ups, I don't have much problem. For dovetails more than a foot wide, especially the last step when you need to glue both sides, I can't seem to get it together without slapping on the stuff -- or going so slow that the glue begins to gel up a little and some of the the squeeze out is in blobs, not liquid.

That all said, my worst hide glued carcass joint seemed to draw up tight as the glue dried, which was pretty cool.

[bob blakeborough]

All interesting points for sure! The finishing aspect seems to be one of the more attractive features by many responses on here. That wasn't something I had realized. I would still like to get an idea on open working time experience once brushed on. Is it a matter of a minute, or much more? etc...

I really think I might have to experiment a bit with this and see what kind of results I can come up with...

[Dave Anderson NH]

For hot hide glue I would use about a minute (literally) for the open time Bob. Again, its is more or less time depending on the temperature of the parts that you are bonding. Parts that are warm or heated will offer you more open time than parts at room temperature (whatever the room temperature is at the time). If the parts are really cool or cold, figure less anything from almost instant gel to about 30 seconds. You are asking a question where the grade of glue, temperatures of the parts, and the glue temp itself are all variables that make a definitive answer almost impossible to give.

As for shelf life on Old Brown Glue, I did some fooling around with a bottle that had some glue in it over 2 years old and still found it usable. I wouldn't recommend using it for anything imprtant and I did not test it against my newer bottle for comparative strength, but it did seem to hold well. Yes, the makers of the glues are conservative in their shelf life estimates. Any other approach and they are courting customer complaints and financial disaster. It's no different than allowing a decent safety factor in an engineering design.

[David Keller NC]

I've used hot hide glue on a few projects. I feel like I need to rush and soak the joints, then clean up the mess afterwords. As others have said, the fact that it doesn't seal off finishes is really great and necessary for my remedial hide glue skills.

I would be very interested in folks describing how they have used hot hide glue for carcass dovetails. For smaller glue ups, I don't have much problem. For dovetails more than a foot wide, especially the last step when you need to glue both sides, I can't seem to get it together without slapping on the stuff -- or going so slow that the glue begins to gel up a little and some of the the squeeze out is in blobs, not liquid.

That all said, my worst hide glued carcass joint seemed to draw up tight as the glue dried, which was pretty cool.

It's incorrect to think that you must get the joint together before the glue gels, but you do need to get the joint together before the glue dries or gets wicked into the wood. Animal hide glue bonds by losing moisture to the wood and surrounding air, which is why one is advised to wait 24 hours before removing the clamps (on a joint that needs clamps).

However, if you prefer to work with the joint before the glue gels, there's a relatively easy way to do it - you just have to locally heat the 2 halves of the joint before you put the glue on. This is an estimate, but you'll get roughly twice the open time assuming your shop is not below 65 degrees F. The easiest way to accomplish this that I know of is with a heat gun, which is a $30 purchase at a home depot.

[David Weaver]

George Wilson should have a much better explanation of things.

Bob and others have pretty much wrapped this thread up. I just talked to George, since he was brought up in this thread - he's out of power now, may have it back tomorrow, maybe a day or two after that, but he'll be back when he's able to get online - he wanted me to relay that.

[tico vogt]

Check out "Hide Glue: Historical and Practical Applications" by Stephen A. Shepherd (http://www.fullchisel.com/blog/?page_id=224). He's the man.

[Larry Feltner]

Try urea formaldehyde. "Plastic Resin Glue". It's made from recycling barnyard manure. No hooves, hide and and cartiledge rendered like hot hide glue. No oil consumed like in PVA, epoxy or poly.

http://www.cpadhesives.com/woodworki...-gallon-bottle

Except for round-tenon joints and chairs, I prefer it over hide glue. Longer open time and more versatile. Authentic for reproductions back to around 1900.

I have heard good things about UF glues, but I've never tried them. I have a couple of questions if you don't mind. What kind of precautions do you need to take when using UF glues since Formaldehyde is considered a harmful substance? Is UF glue repairable like hide glue, or is it more like a PVA in terms of being able to repair a failed joint down the road? Does it show up in your finish if you don't get all the glue cleaned of the joint like a PVA, or is it transparent like hide glue? I appreciate any additional information you might have on UF glues.

[george wilson]

Just about all the good points of hide glue have been covered already. [I] use it on instruments where there may be a need to remove tops,backs,or necks for repair in the future. Years ago,Fine Woodworking did a test of glues,and found that the liquid hide glue was stronger than the old hot type.

Some of the most invisible glue lines I have seen on maple are on Wurlitzer harps. Their workmen actually use Knox unflavored gelatin for hide glue. I mean,it really makes a joint that is well nigh invisible on MAPLE,which is saying something.

[Mike Henderson]

I have heard good things about UF glues, but I've never tried them. I have a couple of questions if you don't mind. What kind of precautions do you need to take when using UF glues since Formaldehyde is considered a harmful substance? Is UF glue repairable like hide glue, or is it more like a PVA in terms of being able to repair a failed joint down the road? Does it show up in your finish if you don't get all the glue cleaned of the joint like a PVA, or is it transparent like hide glue? I appreciate any additional information you might have on UF glues.

UF glues are good but have some drawbacks. All the UF glues that I'm familiar with are two part glues which means you have to mix up the amount of glue you need before you start. So you have to mix more than you need because you don't want to have to go back and mix a new batch during the glue-up process. The powdered UF glue that you mix with water takes some skill to mix so that it's not lumpy.
Second, the glue gives off formaldehyde, not only when you are doing the glue-up but for quite a while afterwards, although the amount is not large. You probably shouldn't use a lot of UF glue in a closed environment.
Third, the glue deteriorates in moist environments. This is probably not a problem for furniture. I have a desk I made in about 1958 with UF glue and it doesn't show any sign of glue failure.
UF glue is not repairable, meaning you can't easily reverse it (take the joint apart). It shows up in your finish, similar to PVA.
On the plus side, UF dries hard so some people prefer it for bent laminations. It has a longer open time than PVA. Some people claim it has gap filling capability but I wonder if it does.

In my opinion, except for certain special applications, I prefer PVA to UF.

Mike

[You can try UF at low cost. Buy a small container of plastic resin glue - DAP Weldwood makes it. You mix it with water and it's dark brown after mixing. It has a shelf life so check the date on the container. It's not used a lot so sometimes the stuff on the shelf is old.]

[Brian Kent]

Matt,

I have seen the words "rubbed joint" but I do not know what that means. Also, by acoustic translucency, does that mean that it does not change the tone of instruments made with hide glue.

Brian

[Pam Niedermayer]

...I have seen the words "rubbed joint" but I do not know what that means....

You plane two edges to mate, slop some glue on both, put them together and rub back and forth until they stick.

Pam

[Chris Fournier]

It's a bit of a misrepresentation to say that hide glue is stronger than... because hide glue can be formulated to any strength. You lose some of the glues other properties when you go for all out strength. Unless you're an instrument maker - particularly of violin family instruments the reversability of hide glue is pretty much just a overhyped selling feature that rarely if ever gets used by the builder.

If you like the idea of hide glue you can easily make rice glue and try that out in your shop - it's pretty fun to stick stuff together with rice.

In the end gluing should follow the KISS principle.

[jamie shard]

This is such a great thread... I wanted to add on just in case someone wanted to chime in on some investigations I'm doing.

One thing that has confused me is all the different recipes for hide glue. One of the challenges in making sense of them is figuring out if the ratios being described are by volume or weight.

Water is about 236 grams per cup.
Depending on the size/density of the crystals, dry hide glue tends to be about 160g per cup.
In recipes that use salt (for glue that is liquid-ish at room temperature), salt is about 273 g per cup.
Here's my notes on different recipes...

Hot Hide Glue (2:1 by weight)

• 200g water
• 100g glue

Soak water and glue overnight, cook, chill overnight. Cut or heat and pour into cubes, wrap in aluminum foil and store in freezer for individual use.

3-2-1 Liquid Hide Glue by volume (pretty close to 2:1:1 by weight)

• 236 g water (3/3 cups * 236g per cups)
• 106 g glue (2/3 cups*160g per cup)
• 91g salt (1/3 *273 g per cup

This version always has un-dissolved salt at the bottom.

3-2-1 liquid by weight (exactly 3:2:1 of course)

• 150g water
• 100g glue
• 50g table salt

Soak water and glue overnight, cook and add salt, chill overnight, cook again – ready for use.

This one also always has undissolved salt at the bottom.

VanEdwards liquid version (about 5:5:1 by volume or pretty dang close to 3:2:1 by weight)

• 1 cup water (236 grams)
• 1 cup glue (160 grams)
• 3 teaspoons tablespoons salt (60 grams)

Or, equivalently:

• 155g water
• 100g glue
• 38g salt

Jamie’s experimental 2:1:10% liquid version

• 200g water
• 100g glue
• 10g salt

NOTE: if salt to glue ration was 10% of total weight (not 10% of glue weight), then it would be 30g which is pretty close to the formula above. The big question is: will 10% keep the glue liquid at room temperature? Answer: no it won't! Next test: try 30g.

It looks like I'm zeroing in on 2:1 by weight for hot hide glue and 200g water, 100g glue, and 30 g salt for liquid.

[Daniel Hartmann]

I've had to reverse a hide glued joint before and let me tell you, it's no easy task. It took an hour with a damp rag and an iron to get the mortise and tenon to the point I could just barely wiggle it apart. That also gave me a ton of confidence in the performance of the glue. Another huge plus for me is hide glues' ability to bond to its self. I had a drawer divider pop loose in its dado on a finished piece. Had it been glued with pva I would have had to remove the old glue but since it was hide glue I was able to just add more glue.

[Anthony Moumar]

I use hot hide glue most of the time simply because I find it more fun to use. I don't really see the point of comparing the strength of hot hide glue, liquid hide glue, modern PVAs ect. They're all going to provided ample strength. I got a old cast iron glue pot of ebay for about $20 and use an electric hot plate to heat it which was also about $20. Preparing the glue hasn't been a huge issue for me. I mix the dry glue with water when I start working. It takes about an hour to let it aborb the water and heat up and it's ready to go. I only really have to make up the glue once or twice a week. If I have glue left over at the end of the day I cover it and put it in the fridge. I find it lasts about 5-7days before it starts to lose its tackiness.

Ive only ever had to reverse the glue once and it's not something I would want to do again. I don't think most people making furnature would have to reverse glue that often for it to be a big advantage. The short open time can be annoying sometimes but I generally not an issue. Sometimes I use a heat gun to heat up the workpieces if I'm doing a more complex glue up. I use 192GS hide glue and I usually have about a minute of open time or two minutes if I heat the wood. The two main reason why I like it better is that it's easier to spread than PVA and it won't ruin the finish if I neglect to clean up some squeeze out.