options to replace urea glue for bent lamination?
eskay57
| Posted in General Discussion on
I’m building some chairs that have bow arms and I need to laminate to create the bow. Is there an alternative to urea-formaldehyde glues for this? I’m in northern Wisconsin and any kind of heavy ventilation is impossible this time of year (for me). 1/4″ red oak, four layers over a form. Not a severe curve, approx. 2″ over 3′.
Replies
I am not an expert in UF glues. So. This is just my experience. I have used the Weldwood UF product numerous times and have not found it to be particularly offensive or to give off much noticeable formaldehyde gas. Unless you are particularly sensitive to it, I don't think you will need "heavy" ventilation. Just enough to pull through a little air while you are are in there. The Weldwood label states that if you can't detect any odor, your ventilation is adequate. After you leave, it won't matter. Reading the label, it appears to be most important to avoid breathing the powder during mixing. So. Work carefully and wear a dust mask during that time.
I don't know about the other brands but, the Weldwood product says not to use it below 70 deg. So, your heater will need to keep up with the ventilation. You should read the safety specs for the product you are using. However, they will probably just say to provide ventilation; not how much.
You might also consider using epoxy. Because of their lack of creep, I don't think you can beat either for bent form laminating. Others might know of some other product.
I have used Unibond UF in a small shop with the door open and a small fan pushing in air from the next room. As bilyo says, good mask on for weighing & mixing. I applied with a small roller to speed it up and took out the trash after clamping. There was no odor at all in the AM. You can choose different color powders to match your project.
I just use exterior PVA left overnight, the creep doesn't bother me too much and often isn't even noticeable. You could compensate for springback with a smaller radius.
Well, I wouldn't laminate arms like that, I would steam bend them. Make the bending form a little tighter radius to account for some springback. If you use air dried lumber, it's not too bad.
There's just something so satisfying about not seeing those glue lines in the armrests.
If you're set on glued laminations, just use yellow PVA glue. I use TBII on rockers for rocking chairs. Very minimal springback with 8 layers of 1/8" oak. Works great.
I have used both PVA and polyurethane glues for bent laminations. On jobs where a long working time is needed, I have found this glue to be the best - now used a lot by boat builders and I get mine from a chandler's store here in the UK.
https://www.collano.com/en
I just bent laminated some walnut for the beams of a bed. I used Ultra Cat from Joe Woodworker. Sets hard, easy to use.
I'll second the ultra cat. Though it still is urea based, they claim it's less than most (including Unibond 800, which works really well, also). Easy to use and I've done some tight bends with great results.
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