Best glue for bent laminating

Best glue for bent laminating · 03-23-2006, 09:03 AM

After reading several articles on glues, and what each one is best used for, I am still confused as to which is best for bent laminating. I have used the yellow stuff for years, usually Titebond II, with good success. But not for any bent stuff.
I am making a bookcase with curving front posts; the arc will not be a tight bend; more of a gentle curve.
If it helps, I am using straight grained fir, resawn into 1/8" strips.
Thanks guys (and gals) if you respond.

DavidF · 03-23-2006, 09:42 AM

http://woodworker.com/cgi-bin/FULLPR...ARTNUM=132-032

This is what I use - highly recomended, but does have a dark glue line. I used to be able to get a white version in the UK called "cascamite" used in the boat building industry. Yellow or white glues will work but there will be more "creep" and therefore springback

woodguy1975 · 03-23-2006, 09:53 AM

I agree with DavidF. PRG is the only way to go. You get water activated ones from DAP or Woodworkers supply or there are a few systems out there with resin/powder combos that have different colors for lighter woods. The PRG from WWS or DAP is great for mahogony, walnut, oak, but too dark for maple and even cherry to me.

Good Luck,

John

DaveO · 03-23-2006, 11:18 AM

There is a good article in the new American Woodworker that just came out on bent wood lamination. They recommended Unibond 800, and a tinting agent can be added to match the glue line to the wood color (lighter or darker)
Dave

woodguy1975 · 03-23-2006, 11:21 AM

Originally Posted by DaveO

There is a good article in the new American Woodworker that just came out on bent wood lamination. They recommended Unibond 800, and a tinting agent can be added to match the glue line to the wood color (lighter or darker)
Dave

Thanks Dave, couldn't remember the name at the time.

John

ChrisMathes · 03-23-2006, 11:23 AM

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Chris

DavidF · 03-23-2006, 11:29 AM

http://www.vacupress.com/veneerglue.htm#prices

jtdums · 03-23-2006, 11:53 AM

Could you use a two part epoxy? Or is this not cost effective and difficult to clean up? I only ask because I have some sitting on the shelf begging me to be used. Plus I get to feel like a mad chemist while mixing the stuff.

DavidF · 03-23-2006, 12:03 PM

It certainly wouldn't be cost effective and I would be worried about the thickness of the glue line that would probably result; it's very difficult to get epoxy to coat well.

woodguy1975 · 03-23-2006, 12:08 PM

I second the vote for not using epoxy. Not a good laminating glue. It is a good gap filling glue though.

michaelgarner · 03-23-2006, 05:45 PM

i agree with davidF and woodguy, epoxy is awsome for filling stuff, like knots that are missing, just put some painters coloring in it and fill the hole to blend it in and make it smooth, I have used unibond and its a great gluing system, if your on time restraints use titebond 3, be blessed.

SkintKnuckle · 03-23-2006, 07:41 PM

It depends on where the bent laminates will be used. If you're planning to use it for interior, any good wood working PVA glue like the Titebonds or other brands will be fine. I recomend that you apply to both surfaces, to minimize dryout and to work as quickly as possible so that the glueline will be wet when clamped. Properly fitted joints, proper clamping pressure and a goodly amount of squeeze-out will give you 100% wood failure if you attempt to rip the glue joints apart after set. Remember that you do not want any significantly wide joints, the glue thickness should be only a few mils to properly bond, so you'll also need to pay particular attention to the jigs you will use to minimize gaps in the glueline.

Generally, in commercial curved plywood laminating applications, catalyzed UF resins are used, but these systems are not available to comsumers, they are slighly more forgiving in a manufacturing environment and much less expensive, present some chemical hazard, and for the most part have extremely short shelf life. If you're interested in this typ system, you can contact CustomPak Adhesives (google it on the net, they have a website), they'll have a product named Cascamite 12S, with is a precatalyzed spray dry UF resin powder which only needs water added, and will cure at room temp in about 12 hours, although I'd give it a little more time. Performance will be as good as those systems used commercially. Note, that I don't have any interest in their business, I only know the folks there and know what they sell.

If your laminated curves are intended for outdoor use, you'll need to either go with the moisture cured polyurethanes (like gorrilla glue and others) or you can go with the top of the line PRF resins which will require catatalyst, these however are expensive and difficult to find in consumer packages. CustomPak mentioned above also carries PRF and the associated catalst, but they are expensive. Both of these systems will give you a dark glue line, with the PRF almost black.

Epoxy is also another option, but most likely will be even more expensive.

Hope this helps.

NCPete · 03-23-2006, 10:48 PM

Martin, that is some great info. thanks!

Mike Wilkins · 03-24-2006, 08:48 AM

Thanks for the replies and info. I did flip through the American Woodworker magazine and saw the article on laminating. I may have to go back and really buy it. Sounds like the Unibond 800 is the way to go. Hopefully one of the Raleigh WW stores carry it.
It will be for an interior application, and this type of project is a first for me. You don't learn anything if you don't try. Wish me luck.

DavidF · 03-24-2006, 10:29 AM

Another problem with using titebond type glues is the short open time. It's amazing how long it takes to spread glue an both sides of a 10 strip laminate, by this time the glue has started to tack and when clamped it will look and feel ok but will not have the strength of a "wet" bond.

Thanks for the info on the unibond and cascamite, that will be my next purchase -come 2020 when my 5Lbs of resin is used! it only takes 3 oz to cover 10sq ft!! why don't the sell "hobby" packs of the stuff, especially as it has about a one year shelf life.

BTW - did you know that - spring back=bent distance/ number of plys (squared) so if you laminate a 10" high arch with 10 plys then the spring back will be 0.1" per side a total of 0.2"
The moral is: the more plys the better