Replies

1. 
   jackiechan | Sep 27, 2003 08:25pm | #1

   Rich,

   Here is a link to Fine Woodworking's "A Working Guide to Glues" article.  This should get you started.  There are three links at the bottom of the article that open up to an excellent comparison chart of all the different types of woodworking adhesives.

   http://www.taunton.com/finewoodworking/pages/w00010.asp

   Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

2. 
   RMillard | Sep 29, 2003 02:47am | #2

   Except for making inlays, I use hide glue exclusively for my work. A Double boiler will work as long as you keep the temperature around 140-150F. Chairs present a challenge when it comes to using hide glue, as it gels so quickly there is little time to accomplish the difficult clamping . Adding urea, purchased from Homestead Finishing products or a pharmacy, will slow the gel time considerably. You must experiment with different ratios of urea to glue to arrive at a mixture that gives you enough open time. The figure I hear as a maximum is 30%, but I have never went the high. Adding the urea to the glue will leave it somewhat gummy for days, so you must give it sufficient time to cure. Salt is also supposed to slow the gel time, but I have never tried it. As for mixing the glue, I just pour on enough water to submerge the granules and let them soak for an hour or so. Heat the glue and add water until you get a nice steady stream flowing off the brush. As the glue is heated, it will loose water and thicken, so you will have to constantly add water to keep this consistency . I also add a little white vinegar to my glue, as it seems to help with the initial tack, although this may not be a desirable quality when working on chairs and other complicated assemblies. The strength of the glue does not really come from any additives, but from the gram strength of the granules, the most commonly available gram strengths are 186(?) and 256, with the higher the number the higher the strength .I use only the 256, so I can’t comment on any other strengths.

   You could also use Franklin Liquid Hide glue or Old Brown Glue sold by W. Patrick Edwards (www.pacbell.net/ebeniste/glue) I use been using the liquid hide glue far quite awhile, and as long as it is fresh and you give it sufficient time to cure you can’t go wrong with it. The Old Brown Glue has proven to be excellent , but I have only been using it for a very short time. It also takes quite awhile to cure. The advantage of these glues are that they of course don’t require heating, and they give a very long open time.

                                         Rob Millard

1. 
   trialnut | Sep 29, 2003 12:57pm | #3

   Rob

   Thank you for the info. These chairs have been rather labor intebsive so I don't want to mess something up during the glue up. Just a couple more questions. Does the urea affect the strength of the glue?  Is the liquid glue as strong as the granuals? How long do you leave the clamps on and how much clamp pressure compared to PVA? How long does the liquid glue take to cure enough for the chairs to be used? I don't think I will need to much open time as I am going to glue up sub assemblies then the whole. I suspect no more than 5min from start of glue spreading to clamps on. Will that be to much for the granules type?

   Again thanks for the help.

   RichThe Professional Termite

1. 
   RMillard | Sep 30, 2003 02:02pm | #4

   It is my experience, and I’ve also read this, that the urea does not effect the ultimate strength of the joint. I would have to say, that I think the liquid hide glue is probably weaker than the hot hide glue, but it still makes a bond stronger than the wood itself. The clamp pressure is really no different with the hide vs. PVA glue. I thinkgiven a warm shop environment, you could extend the gel time of the hide glue to 5 min. and complete your glue up. The cure time with the liquid glue before removing the clamps, should be at least 12 hours and the full strenght may take 2-3 days. Hot hide glue with the urea would require the same clamp and cure time, but it may gain its full cure in a little less time. Also, the squeeze out with both glues will feel gummy for quite some time, but the thickness in a properly fitted joint is so thin it will harden (cure) much faster in the joint.

1. 
   trialnut | Oct 01, 2003 01:12pm | #5

   Rob

   Thanks again for your help. I think I have enough info now to proceed with caution full speed ahead. Am going to experment with some scraps first to make sure of my working time and such.

   RichThe Professional Termite