Replies

1. 
   AdamCherubini | Dec 18, 2006 05:35am | #1

   Don,

   What hour are you talking about?

   Here's how i do it. I start with dry - unaltered hide glue. I like to pre soak it overnight. I think this changes the gell time. I heat it in a cast iron doubler bioler type traditional glue pot on a single electric burner. When I'm ready to glue up a carcass, I bring the whole pot- inner and outer, to my bench. This keeps the glue in the pot usable.

   I brush the watery glue on to my pins quickly and set them in the tails. I think I have less than 5 minutes before the glue gells on the cold wood. Then I repeat for the other side of the carcass. With that on, I check it for square.

   About clamping: I don't. In general, hide glue, like epoxy needs a low pressure bond. If you squeeze it too hard, all the glue will extrude out. PVA requires the clamps and cauls and 150-250psi of bondline pressure. Now in a dovetailed carcass, the clamps (depending on how you clamp it) put pressure on the end grain joint that does very little. The joint you need to clamp with PVA is the long grain of the pins and tails. (there's actually more to this story- email me if you want to hear it).

   The hide glue will grab in 10-30 minutes, but won't achieve full strength for hours at least. But you can continue working, almost continuously and better without clamps.

   Nowadays, I find titebond inconvenient for everything except long edge joints. Otherwise, hot hide glue is simply the better glue system for cabinetry (especially joinery).

   Adam

1. 
   DonStephan | Dec 20, 2006 05:39am | #2

   Thanks for the information and your time. Perhaps I interpolated from a thread on veneering with hide glue, but for some reason I was thinking hot hide glue not only grabbed but actually set soon after it contacted room temperature wood, so much so that the joint couldn't be disturbed. I'm going to look for a user in my area and ask if I can attend the next time he is assembling a piece of furniture.One of your comments has piqued my curiosity. As I was edge gluing a table top this afternoon I started to wonder if hide glue, since it dries harder than PVA, would be a better choice for table top edges. I'm not thinking of its rub joint characteristic but rather the tendency of PVA to creep out of edge joints on flat surfaces and telegraph the joint over time. You have more woodworking experience than me, and I've never used hot hide glue - mind sharing your experience on edge joints?Thanks for all.Don

1. 
   AdamCherubini | Dec 20, 2006 06:01am | #3

   What it does is gell. In the pot, its got little viscosity. As it chills, it gells into a rubbery like material, not unlike a sticky form of dried silicone caulk. The time it takes to gell varies. On a cold surface, it might gell in minutes. But it could stay that way for up to an hour ( I'm guessing). I think I like to peel off gelled drips in maybe 20 minutes or so. Its still soft then.From gell to brittle takes a while. I don't know exactly how much you can move it during that time. A few hours later forget it. The drips are like epoxy. They will shatter. Its actually not fun to remove with either chisel or plane. If you use a chisel wear safety glasses.Without an apprentice, I really can't do long edge joints with hide glue. I generally spring my joints so clamps are a neccessity. I just never have time (with unaltered glue) to get the clamps on before it gells. Once it gells, you can't pull up a gap. With my old wooden jointer plane and Titebond II, I can make long joints that are almost undetectable.Adam

2. 
   joinerswork | Dec 20, 2006 05:41pm | #4

   Don,

   I get hide glue from Bjorn Industries, in Charlotte NC (704) 364-1186. When I first called, he wanted to know what kind of work I was planning on using it for, as he had several types with different gel times.  For mostly repair work, and re-assembly of joints on antiques,  I ended up getting  #135 grade glue, which he said would give me more time to align broken parts, than some of his other grades of hide glues.   I guess that has something to do with its "gram strength" whatever that is.  The more "potent" the glue, the higher the strength (to the point that it will pull a chip off a piece of glass as it dries), but also the faster it gels.  The amt of water added once it is mixed, will also affect gel time, but beyond a certain point, also its ultimate holding ability, obviously.

   Urea crystals are recommended as an additive to hide glue, to extend gel time.  I've read that this is what makes "liquid hide glue" not gel at all at room temp.  I can't speak to this from experience, as I've never used the crystals, and don't care for the store bought liquid hide glue.  I've read that old timers used to pi$$ in their glue pot to extend gel time.  Maybe the smell just made glue ups seem to take longer...

   Also pre- warming the surfaces to be glued, will give you a little more time to get your ducks in a row.

   Regards,

   Ray Pine

1. 
   Yogi | Dec 22, 2006 08:14am | #10

   Ray-  Noted your dislike of liquid hide glue and am wondering in what way you find it unsatisfactory-  I've used it quite a lot, but I'm always ready for a better mouse trap-  You've had a lot of experience with hot hide glue and I've had none, so you're a guy who could compare the merits of the two-  How do they compare, in your experience, and how do you find the hot variety superior?  Thanks-  Yogi

1. 
   joinerswork | Dec 22, 2006 08:11pm | #12

   Yogi,

   My experience with liquid hide glue was that it took longer to dry than I liked, compared to hot hide glue.  Plus the film spread around the rub-jointed glue block seemed to remain a bit tacky, even after it was "dry".  Maybe the glue was a little past its prime.  I remember an instance in a shop where I worked where the "Peter Cooper" brand liquid hide glue went south and refused to harden at all.

   Regards,

   Ray

3. 
   DonStephan | Dec 21, 2006 03:47am | #5

   Thanks to both of you for taking the time to respond and educate me. Now I'm confident hot hide glue can be used without sacrificing more than perhaps a little efficiency. After the first of the year I'll browse some articles, books and the internet on gram strength and urea crystals, get a glue pot and start experimenting.

   Have a good week and holiday weekend.

1. 
   SteveSchoene | Dec 21, 2006 06:49am | #6

   Don't buy an expensive glue pot.  A crock pot--slow cooker, will likely work just as well at 1/5th the price if you buy one new, and at 1/20th of the price if you pick up one at a "Goodwill" store or tag sale. 

4. 
   RMillard | Dec 21, 2006 08:04am | #7

    

   Hide glue takes some getting use to, but I wouldn't trade it for any other glue.

   As long as the glue is still liquid when the parts mate, you'll get a good bond. The problem is,  even in relatively warm weather, the glue can gel quickly. I have done everything from warming the wood by a heat source ( baseboard heater, heat lamp etc) to placing small pieces in the oven ( which makes me decidedly unpopular in certain domestic circles)

   For more complex assemblies I add a little urea. I believe I've read that you can add up to 30% urea, but I've never even approached this ratio. The urea will make the glue seem to remain rubbery for an extended period, but in the thickness you'd find in a well fitted joint, it will cure to a strength similar to, if not identical to unaltered glue. I've never tried to use lower gram strength glue as a way to gain more assembly time, because the urea works well, and even if the urea did weaken the bond a bit, I'd still be ahead of, or equal to starting with a lower strength glue.

   The only time, I've really worried about using hide glue for an assembly, is when building a sideboard. The first one I made, I used white glue. The next two, I used liquid hide glue. The last one I made I used hot hide glue with urea added, and the assembly was hectic to say the least; mostly because I did not want to over do the urea additive.

   Rob Millard

   
   

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   Edited 12/22/2006 9:03 pm ET by RMillard

1. 
   jackplane | Dec 21, 2006 07:32pm | #8

   hello Rob,

   i haven't found urea from any local supplier- can you tell me where you get yours?

   cheers,

   jp 

1. 
   RMillard | Dec 22, 2006 02:21am | #9

   I got mine from a local pharmacist, but Homestead Finishing Products, sells it too.

   Rob Millard

    

2. 
   AdamCherubini | Dec 22, 2006 04:49pm | #11

   You can substitute any salt for urea, even table salt. But the easiest thing to do is probably just used franklin's liquid hide glue as the additive. Liquid hide glue is nothing but regular hot hide glue and urea.I gotta tell ya, I don't do this (I have- but I don't typically). I don't find the need to diminish the properties that I like about hide glue- the quick grab, the stiff bond line, which urea does. etc.One thing tho that improves is reversability. Salts make hide glue easier to (absorb water) reverse. So...One more thing- gram weight is an expression of molecular weight. So higher gram strength glues have higher molecular weights. But repeated cooks or cooking at too high a temperature, breaks down those long chains and results in weaker glue that sets up slower.The part I don't fully understand is the degree of cross linking between those molecules. Obviously, hide glue exhibits a high degree of cross linking (which produces stiffness- long polymer chains without cross linking causes elasticity). So in addition to reducing the molecular weight (shorter chains), repeated cooks also seems to reduce stiffness, so is it reducing cross linking too? I think so.Adam