Hide glue and urea

[Randy Klein]

I'm going to start experimenting with hot hide glue and have some questions. I've read in several places that adding urea will extend the open time.

Now is this pure urea or just short hand writing of urea-formaldehyde? 'Cause that's a big difference.

And where do you buy urea?

[Sam Yerardi]

Pure urea. It can be obtained from chemical supply stores. The problem with urea (15-15% by dry weight is typically what gets added to the glue) is that while it does lengthen working time, it may allow creep or increased flexibility which is why luthiers (musical instrument builders) usually won't use it.

I also want to add that the human body produces urea in waste, and pure urea can be irritating to skin and eyes, and harmful in large amounts.

[Alan Schwabacher]

Some young apprentice probably discovered how to make foul smelling extended time hide glue when he didn't take the time to step outside for a moment.

I'm pretty sure that "old brown glue" is simply a decent grade of hide glue with urea in it. If you want less urea, you could mix it with ordinary hide glue.
http://www.wpatrickedwards.com/gluepage.htm

Urea is certainly available from chemical suppliers, but probably also from agricultural places as it's sometimes used in fertilizer as a nitrogen source. The challenge would probably be in finding a small enough quantity for sale.

[Randy Klein]

I also want to add that the human body produces urea in waste

I knew that tidbit, but I figured my wife would disapprove if she saw me adding it to the glue in that form.

[Rob Millard]

Randy,

We are in the same neck of the woods. I got my first batch of urea from Ken’s Pharmacy in Vandalia ( they had to special order it and I knew Ken’s wife). Now I get it from Jeff Jewitt at Homestead Finishing.
Rob Millard

[Randy Klein]

Randy,

We are in the same neck of the woods. I got my first batch of urea from Ken’s Pharmacy in Vandalia ( they had to special order it and I knew Ken’s wife). Now I get it from Jeff Jewitt at Homestead Finishing.
Rob Millard

Rob,

I was hoping you'd chime in. Thanks for the tip on Homestead, I never thought about them.

As a follow-up question, I read in the PW article on your shop that it is unheated. How do you manage to use hide glue during the cold winter months as everything I've read says it will gel too quickly?

[Rob Millard]

Rob,

I was hoping you'd chime in. Thanks for the tip on Homestead, I never thought about them.

As a follow-up question, I read in the PW article on your shop that it is unheated. How do you manage to use hide glue during the cold winter months as everything I've read says it will gel too quickly?

Randy,

I have a small (very small) room at the back of the shop that is heated 24/7, so I store the project in there. Durning the day I have a overhead quartz heater and now a piece of baseboard heat. On very cold days I get out a kerosene heater, but I dislike it so I don't use it often.
I break the glue ups down into many steps; for example a small side table is glued up in 3 steps. I once glued up a sideboard in early Decmeber, but I won't do that again, as they are hard enough to do in July.
Rob Millard

[Randy Klein]

Now I get it from Jeff Jewitt at Homestead Finishing.
Rob Millard

I also found it at Pianoteksupply.com for a whole lot less $$. I've emailed both parties and they seem to be the exact same product. I'm not sure why there is a huge discrepancy between the two prices though.

Unfortunately due to minimum order at pianotek, I have to order 3lbs of Urea. Guess that'll last the rest of my life...

[David DeCristoforo]

Could I make a suggestion here? Since you are just starting to experiment with hot glue, forget the urea for the time being. If you start out using "modified" glue, you will not have a good "frame of reference" to make any comparisons. If you use the glue "straight" for a while, you will develop an understanding of how it works and what its properties, advantages and limitations are. Then, if you do decide to start playing with additives, you will be in a much better position to evaluate the effects.

[Eddie Darby]

How much time are you looking for?