Replies

1. 
   BG | Feb 05, 2004 11:21pm | #1

   Rats, I was kinda hoping it was just the dryness and once some moisture returned the legs would move back..

   This past summer I disassembled some plywood cabinets I had made about 2.5 years ago using yellow glue....the sides practically slid out of the dados ...the glue was useless.  I've stopped using it since last summer. 
1. 
   JohnWW | Feb 06, 2004 01:31am | #2

   I think the glue may be getting a bum rap here. 

   If the two pieces of stock you glued together were flat grained rather than quarter sawn, and the orientation of the rings was in opposite directions, then there would be a lot of unnecessary stress on the glue line when the two pieces cupped in opposing directions as the moisture content dropped.

   Yellow glue when properly used makes very sturdy joints in plywood, if your cabinets came apart that easily I doubt that the fault was primarily with the glue.

   John W.

    

   Edited 2/5/2004 6:29:38 PM ET by JohnW

1. 
   BG | Feb 06, 2004 03:26am | #3

   JohnW,

   Shouldn't I get max strength gluing long grain to long grain...and isn't  that maximized with quarter sawn?  (I'm really asking, not challanging)

   The other incident I had with yellow glue was with cauls.  I made several cauls gluing two pieces of 2" square oak together.  Again, after about two years I ripped 1.5" off each side of the caul (needed the wood for slats) leaving about a 1" piece of stock with a glue line in the middle...I pulled it apart with my hands.  Needless to say my trust with yellow glue has been shattered.  Maybe I'm doing it wrong but none of these joints were starved..

1. 
   JohnWW | Feb 06, 2004 04:18am | #4

   BG,

   Whether or not the pieces were flat sawn or quarter sawn, they would still be glued up long grain to long grain. 

   Looking at the crosscut end of a board, a flatsawn board would have it's rings running more or less parallel to the wide face of the board.  A flatsawn board will cup when it gains and loses moisture, this is not a defect of the wood, nor is it caused by how the wood was dried.  In addition to cupping, a flatsawn board will also expand and contract a fair amount across its width as its moisture content changes. 

   On a flatsawn board, the rings will appear to straighten out if the wood loses moisture and the face of the board will taken on a curve as this happens.  If the board gains moisture, the rings will become more sharply curved and the board will cup in the opposite direction from when it was drying.

   If you glue two flatsawn boards together with the rings curving in opposite directions, the boards will cup in opposite directions when the piece gains or loses moisture, creating stresses that will possibly break the glue line or crack the boards.

   A quarter sawn board will have the rings running at right angles to the wide faces.  A quarter sawn board will remain flat as it gains or loses moisture and its expansion and contraction across its width will be around half that of a flat sawn board.

   The best glue up for a leg to be turned would be to glue together two quarter sawn boards.  The second best alignment would be to glue together two flatsawn boards with the rings curved in the same direction.  Gluing two flatsawn boards together with the rings curved oppositely is the worst alignment for the reasons explained earlier.  Gluing a flat sawn board to a quarter sawn board will also create stresses and should likewise be avoided.

   Regarding the cauls, my first suspicion is that the glue was either very old or it had frozen at some point before it was used.  Other possibilities are contamination of the woods surface or the wood was burnished by being planed by very dull blades in a jointer or planer.  A last possibility is the glue up was done in a cold shop and the glue never cured properly.  I have never seen a properly made yellow glue joint that wasn't stronger than the wood itself when tested.

   Hope this helps, John W.

    

    

    

   Edited 2/5/2004 8:55:23 PM ET by JohnW

   Edited 2/5/2004 9:09:49 PM ET by JohnW

1. 
   BG | Feb 06, 2004 05:15am | #5

   JohnW,

   Thanks, I do appreciate the comments and insights.

2. 
   Badjeros | Feb 15, 2004 12:02am | #6

   What do you use instead of yellow glue and why?

   Thank you in advance for your reply.

1. 
   RMillard | Feb 15, 2004 05:12am | #7

   none,

   I use hide glue, both the liquid and hot varieties, almost exclusively. I have several reasons for favoring hide glue. First is its adaptability, it can be used for rubbed joints, veneering, gluing fabric or leather writing surfaces, making flexible glue lines with the addition of glycerin ( such as the muslin reinforcement of highboy hoods, I've personally never done this ), extended set time glue, with the addition of urea, and last but not least extremely strong rigid glue joints. Another reason, is hide glue's centuries old, proven track record, which can't be matched by any modern glue. While I'll admit this is probably not a big deal, I like to know that the glue I use will last for not only my lifetime, but many lifetimes. Last, is its easy of reparability. Hide glue will bond quite nicely to itself, so a failed joint is easy to repair. This may sound less than inspiring, but I believe this is the reason that so many antiques survive, since all joints will at some point fail, being able to easily re-glue and end up with a strong joint is a real plus. I don't believe any modern glue has all or even most of these attributes.

   Now that I have sung the praises of hide glue, here are its drawbacks. Hot hide glue gels so quickly that it can be a challenge to glue up any but the simplest project. The addition of urea will slow the gel time down, but it does have a small effect on the strength . Hot hide glue has to mixed fresh nearly every day, although I keep mine for up to 3 days in cool weather. It has a smell that isn't exactly appealing.

   Liquid hide glue has to be fresh ( bottles are marked with an expiration date) or it will produce poor bonds. It is not as strong as hot hide glue, at least not initially, because the gel depressants, cause it to remain somewhat gummy for days. I too has a characteristic odor, that isn't pleasant .

   I use white glue to make up the inlay bandings that are part of my work, simply for its easy of use and long open time. In the finished piece hide glue will be used to adhere the inlays. I would also use white glue if I were making things such as kitchen cabinets, entertainment centers and other items that probably won't have a long service life, where hide glues time tested durability wouldn't be an advantage.

   I have gotten good results with yellow glue, but I have also had poor results. In fact my only failed joint was done with yellow glue ( Tite Bond II) The poor results were most likely from using old glue, but even fresh glue seemed to be less rigid than white glue, and certainly no where near that of hide glue. The failed joint was done with a fresh bottle of glue ( free sample at a woodworking show), so that of course took Tite Bond II off my list.

   Rob Millard

1. 
   Badjeros | Feb 18, 2004 08:56pm | #9

   RMillard,

   Thank you for your informative response, I will take in under advisement for future projects.

   Once again, Thank You.

   -None

3. 
   Heatherington | Feb 15, 2004 06:04am | #8

   I have been having my doubts about yellow, or white glue, lately. I just got two jugs of epoxy. What are you using? 

   After I read on down, I see that as always I'm here late. Have you used any epoxys? If you have, which do you like, and why?

   I'm going to go to them because I'm going to start making signs as a way of making money to finance making pretty stuff, and signs get put up out in the weather

   
   

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   Edited 2/14/2004 10:20:02 PM ET by sparks