Strip Laminating Teak

Advice on adhesives and techniques for gluing up Teak strips to make rough stock for a curved moulding profile. June 26, 2009

Question
Does anyone have any direct experience strip laminating Teak? The first question would be what to expect regarding springback. Something like hard maple?

Second question would be what glue types were used. I've had success in the past with Titebond for interior applications, but this was with more normal straight line gluing applications where there was no springback pressure. I'd like to plan this with West Systems but haven't called their tech dept. yet to inquire on the suitability.

Forum Responses
(Architectural Woodworking Forum)
From contributor A:
I am actually doing that exact thing right now. I did not even bother with titebond and am using only West System. So far everything is fine. The teak quickly dulled my HSS planer knives and left a hammered finish on the wood which I felt was unacceptable for gluing lams. A 60 grit on my wide belt works as long as you run the boards skewed, they do not load up. Spring back has not been an issue and the thickness of the layers seem to fall in line with maple like you said. The only issue I am having is cutting the profile on the final glued up laminate. The springback and twist that results after I cut the profile is more pronounced than anything I have ever seen, probably due to uneven release of stresses. More laminates would help, but as you know, teak eats up tooling so the less machining the better.



From the original questioner:
Thank you, thank you, thank you! This will be a 1" x 3-1/2" S4S glue up at large radius. I'll be bringing in the strips resawn at 1/4" and taking them through the Timesaver with 60 grit to bring them down to 6 strips per 1" glue. Thanks for the tip on running them through at an angle.


From contributor B:
I question the use of Epoxy with teak for bent laminating. Epoxy does not cure brittle hard but remains someone flexible. This is good for adhesion but maybe not so good for resisting spring-back or unwind. Teak is another problem because of the natural oils within the wood (even after the acetone wipe). These two factors may be combining and working against your best laid plans. There's already an endless amount of discussion on this topic but I still think it's worth mentioning. I like the excess glue beads to break like glass when I scrape the top. If it's rubbery or a bit soft, common sense tells me I should expect some give along the glue lines.



From contributor C:
Epoxy would be my choice for this. I use it for all of my bent laminating. While there is nothing wrong with the West brand, I gave it up a long time ago because of price. When I use it for an adhesive, I usually thicken it with colloidal silica to about the consistency of latex paint. This makes it less brittle, and helps bridge better. Epoxy likes a fatter glue line than most other glue, so less pressure is better than squeezing it all out of the joint with too much for the slow setting time. If you are using it for some of your trim work, I use some of the packaging tube, made to be cut to length and heat sealed for long slender bags, with a vacuum, and only enough clamps to hold it to the form.


From the original questioner:
To contributor C: It sounds like you are making your own polytubing. This stuff is available ready made on rolls and is rather inexpensive. We keep widths from 4" to 16" on take off reels here in the shop. It's available from a number of sources such as McMaster-Carr and U-Line. We use 4 mil to wrap our mouldings for delivery and 6 mil for vacuum pressing just as you described.


From contributor D:
While I don't have experience laminating teak, I've always liked Weldwood plastic resin for bent lams. It dries hard as glass(I've cut myself on the squeeze out) and has the least spring back of anything I've tried. I'd call the manufacturer and ask about using it on teak.

From contributor E:
Use epoxy, West is good. If you are using alot, you can buy it generic from boat supplies or a skateboard maker supplier for less. There is very little spring back, in fact, it does dry hard. It works.


From contributor F:
I'm not sure which brand of epoxy resin you have used which has remained flexible, but the vast majority are very brittle (hard). I would not trust any other glue for teak except resorcinal.


From contributor G:
If your epoxy is not curing hard, I'd suspect you're not getting the ratio correct. Some brands are slightly more forgiving than others, but some require exact ratios. I had some inconsistent results with West until I discovered the culprit. I leave the pumps in the can, and found the stuff dripped out and made a gooey mess on the shelf. I didn't think much of it until I had a couple batches not set hard, and then reasoned out the problem. When my shop temperature went above the temperature I last used the epoxy, which it invariably would at some point, the expansion in the can pushed out a little of the product. Then when the temp went down, contraction caused it to suck a little air back into the pump. The result was that one pump stroke did not deliver the correct volume of resin/hardener. Since then I always give the pump a little half-stroke to "burp" it. A little more expensive to waste that bit, but perfect mixes ever since.


The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor P:
We always use epoxy here in the tropics for all of our exterior joinery. Itís a little more expensive but less so than comebacks. Laminations work out just fine in teak and we have not had problems with springback after molding laminated blanks. Just be sure your resin/hardener proportions are spot on as contributor G said and don't squeeze the joints dry.