Hide glue joint and repairing
#9
I typically use liquid hide glue (Titebond). It is easy to use and seems to hold well. And I've always heard that hide glue bonds can be repaired, etc. But everything is I've ever seen talks about getting the joint apart (heat and water). I haven't ever seen anything talking about getting the joint back together. Is it simply get the joint to release, do any necessary repairs, and then use hide glue to put it back together? Or are you supposed to do anything to the joint after you get it apart? Kept up with heat and humidity till you get most of the glue off?

No planned repairs right now, just curious.

Mark

Reply
#10
I use obg (the liquid hide glue should be the same). If the glue is relatively fresh ---- days or weeks old, I unglue parts, fix whatever needed, and reglue joint with more obg.

If hide glue is years or even decades old, remove the glue with a scraper first to expose new wood fibers before applying fresh glue. If vintage pieces I come across have been fixed by someone using modern glue over hide glue residue. I scrape joints down to the bone before using hide glue.

Simon
Reply
#11
(09-27-2021, 02:41 PM)msweig Wrote: I typically use liquid hide glue (Titebond). It is easy to use and seems to hold well. And I've always heard that hide glue bonds can be repaired, etc.  But everything is I've ever seen talks about getting the joint apart (heat and water). I haven't ever seen anything talking about getting the joint back together.  Is it simply get the joint to release, do any necessary repairs, and then use hide glue to put it back together?  Or are you supposed to do anything to the joint after you get it apart? Kept up with heat and humidity till you get most of the glue off?

No planned repairs right now, just curious.

Mark

I've done that exactly once, using Titebond liquid hide glue. Hit it with a heat gun until it came apart, threw away the piece I didn't care for (with mortise), reglued with new end piece. I believe I heated the LHG, applied it, and clamped it up. That's it. Granted, I threw away half of the joint and replaced it with a new one. But I didn't have to do anything special. I'm sure I dry fitted it, as we always do. I might have knocked off of a little of the previous layer with a card scraper or old file.

Refitting was easy. The hard part was not scorching the wood with the heat gun.
Best,
Aram, always learning

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Antoine de Saint-Exupery


Web: My woodworking photo site
Reply
#12
Mark ,  I only work with hot hide glue, but assuming the liquid works the same, you do not need to remove any glue from the joint.  Hide glue will stick it itself, that is one of the benefits over some modern glues.
Reply
#13
Scrape the old glue off before re-assembly you should be fine.

Hide glue is a gap filler to a degree.
Reply
#14
I've taken to scraping off old hide glue out of an abundance of caution. But I also don't go nuts about it. In the past I've done nothing more than remove any "chunks". 

PVA and any other kind I can' identify, scrape to bare wood if possible/
Don't sweat the petty things and don't pet the sweaty things. -- G. Carlin
Reply
#15
(09-27-2021, 02:41 PM)msweig Wrote: I typically use liquid hide glue (Titebond). It is easy to use and seems to hold well. And I've always heard that hide glue bonds can be repaired, etc.  But everything is I've ever seen talks about getting the joint apart (heat and water). I haven't ever seen anything talking about getting the joint back together.  Is it simply get the joint to release, do any necessary repairs, and then use hide glue to put it back together?  Or are you supposed to do anything to the joint after you get it apart? Kept up with heat and humidity till you get most of the glue off?

No planned repairs right now, just curious.

Mark

  I own a woodwork and furniture repair shop, probably 1/3 of the furniture I repair was originally assembled with hide glue. I've used the Titebond hide glue before but I don't any more. I read a couple of articles on using hide glue and they've said that liquid hide glue has urea or other chemicals added to keep it in the liquid form. This was reported to weaken it to some degree and I don't want to risk any repair I make failing. I use hide glue often but I use a glue pot to melt it. I keep some in the refrigerator mixed with water in a gelled state and I cut it into blocks and toss them into the pot 15 or so minutes before I need to use it. When I'm done I just pour what's left into the container and back in the fridge it goes. While the convenience of the liquid hide glue appeals to me, a little more work and a little wait while it melts for stronger joint is worth it to me. Lee Valley has a small glue pot set up that works great for repairs, so you don't have to make or melt a whole pint or so.
   The ability to get a joint apart in the future makes hide glue a great choice, hide glue does as someone else said have some gap filling qualities due to the body it has and it absorbs stain fairly well too. I believe it it was in one of Bob Flexner's books or articles I read, that injecting the joints with denatured alcohol will help crystalize the hide glue and weaken it for disassembling old pieces. I have done this and it does help in certain cases. If I can't get warm water to get it apart, I will inject DA into the joint and it has helped on many occasions. 

Paul
Reply
#16
(09-30-2021, 11:59 PM)PaulM85 Wrote:   I own a woodwork and furniture repair shop, probably 1/3 of the furniture I repair was originally assembled with hide glue. I've used the Titebond hide glue before but I don't any more. I read a couple of articles on using hide glue and they've said that liquid hide glue has urea or other chemicals added to keep it in the liquid form. This was reported to weaken it to some degree and I don't want to risk any repair I make failing. I use hide glue often but I use a glue pot to melt it. I keep some in the refrigerator mixed with water in a gelled state and I cut it into blocks and toss them into the pot 15 or so minutes before I need to use it. When I'm done I just pour what's left into the container and back in the fridge it goes. While the convenience of the liquid hide glue appeals to me, a little more work and a little wait while it melts for stronger joint is worth it to me. Lee Valley has a small glue pot set up that works great for repairs, so you don't have to make or melt a whole pint or so.
   The ability to get a joint apart in the future makes hide glue a great choice, hide glue does as someone else said have some gap filling qualities due to the body it has and it absorbs stain fairly well too. I believe it it was in one of Bob Flexner's books or articles I read, that injecting the joints with denatured alcohol will help crystalize the hide glue and weaken it for disassembling old pieces. I have done this and it does help in certain cases. If I can't get warm water to get it apart, I will inject DA into the joint and it has helped on many occasions. 

Paul

Paul, next time you need to disassemble a hide glue joint, try Everclear. It works way better than denatured, and it's what we luthiers use. Totally agree with your thoughts on hot vs. liquid hide glue. The liquid stuff fails when exposed to a high RH/ high temperature environment.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)

Product Recommendations

Here are some supplies and tools we find essential in our everyday work around the shop. We may receive a commission from sales referred by our links; however, we have carefully selected these products for their usefulness and quality.