Glue Failure with Cedar

Troubleshooting a set and bond failure when gluing up a laminated Cedar decorative beam. October 20, 2013

I took on a small project of straight-lining and gluing up some KD vertical grain 12/4 western red cedar beams. Other than getting the straight line on up to 18 foot lengths I figured this to be a routine operation. I bought a fresh gallon of Type II and clamped up the first set. After five hours (at 60degrees) the glue still wasn't set. On the next set I draped some tarps over and put in a small heater which raised the temp to 70 plus. It still seems like the glue is really slow to bite. I have used Titebond for 30 plus years in warm and cold environments and it's always been a quick bond/tack and usually I can pull clamps in a one hour max. Did I get a bad batch (old stock from the box store)? At this rate I could be at this for over a week!

Forum Responses
(Adhesive Forum)
From contributor P:
I suspect that your moisture content was abnormally high. Titebond II cures by losing moisture (as well as chemically). If the moisture of the cedar is too high it will drastically affect the cure rate. Also, I would question the use of this kind of glue in manufacturing beams.

From the original questioner:
The beams are at 6-10% - almost too dry for my taste. I think the 18 footers weigh less than 60lbs! They are not for industrial use and are going arranged as a display climate controlled room in a museum. All they need to do is stand there and look pretty.

From the original questioner:
Today I glued two more pieces, draped tarps over it, and put a small heater underneath. By 8:30 it was 80 inside, at noon it was 82, and the temp help steady. I just pulled the clamps at 5 P.M. and saw the joint move. All it took to completely separate the two pieces was a door shim tapped in at each end, then three more along the 18 foot line and "pop" - not one area was bonded good enough to pull even the slightest sliver Heck I remember once cussing type II because it tacked in about ten minutes! Now I don't trust the few that I have I already set aside. I will have to separate them and start over with a new batch of glue. I am tempted to go with Resorcinol but I had a bad batch of that before too. Maybe Type III?

From the original questioner:
I found this below and it answers the questions.

“Years ago, I did some testing with Titebond and Titebond II on cedar. Both failed and I was advised by Franklin Adhesives to wash the surfaces with acetone prior to glue up. The acetone test also failed. Since then, I've used polyurethane glue on cedar and had no failures. When Titebond 3 came out I did a test with that and the joint held as the wood split apart. So TB3 is probably a good alternative. However, I will stay with the polyurethane. We do cedar jamb laminations with it on a regular basis.”

From contributor E:
TB 2 has a chalking temp of 55degrees. That mean everything has to be above 55 degrees. If your stock is below that temp and you glue it up then you will likely have a failure.

From Contributor M:
Do you have some small sacrificial pieces available for a test? Try Gorilla glue and don't forget to dampen the faces before applying the glue.