Plastic Resin Vs. Gorilla Glue for Jatoba Bender Rail

[Todd Jensen]

I'm bending up a couple of Jatoba handrails in the coming week and was sold on using the Dap Weldwood plastic resin glue to reduce springback. The problem is that all the glue I'm finding locally is older than the recommended shelf life(I called Dap and have been calling them from every store with the batch numbers:rolleyes: ). Anyways, I've got a stairguy peer that recommends I just use Gorilla glue instead. I'm considering it but looking for any other input. Typically I use Titebond II for bender rail, but am really trying to minimize springback on the Jatoba. Its November in the great northwest and despite being indoors, the humidity and cold seems to still affect glue-ups. Thanks for any advice/input -

Todd

[Craig D Peltier]

Gorilla Glue came in last in strength in Finewoodworking a couple of months ago. Titebond II First.

[Jamie Buxton]

Polyurethane glue (Gorilla) foams up as it cures. If your work isn't securely clamped together everyplace, it will push the laminates apart. On top of that, the squeeze-out foams up and gets all over everything -- clamps, forms, the stairs, you name it. I'd keep looking for ureaformaldehyde. If you can't find UF, look for a good epoxy like System 3 or West System. You can get System 3 at Woodcraft. Boating-supply places like West Marine have West Systems.

[Todd Jensen]

Do you know which between UF and system 3 would leave a darker glue line? I'm also curious about open time with the system 3. I'm over the gorilla glue option; the idea of scraping off all that dried foam isn't appealing at all and something I had originally blown off as no big deal, but realistically I have no interest in it. I might try a test batch with the newest bucket of UF I found(a year old or so unopened, give or take), and go from there. Any more info on the system 3 or UF would be appreciated ; on the bucket of the UF it says to mix with 68 degree water, but I've heard it mixes better with colder water. Thanks for the info and any addt'l...

[Bob Smalser]

I've consistently found that springback has to do with the number of lams, not the glue you use. More lams=less springback.

I've tried liquid poly with success on a number of lammed boat knees in Doug Fir, but I don't recommend it because I can replace those knees if they ever fail a lot easier than your handrail. "Strength" as FWW measured it is completely moot. All glue has to be is stronger than the wood it bonds. Much more important is open time, repairability and creep, and there Titebond fails miserably compared to poly, let alone UF resin with its stiffness and easily-sanded glueline. An old heat blanket or two from Good Will solves any concerns about curing temperature.

Here's a good source for guaranteed fresh glues at good prices. They even have hide glue:

http://cpadhesives.com

[Todd Jensen]

Thanks Bob. I'm definitely going to use the UF/plastic resin this go-round, and appreciate the advice.

[Justin Bukoski]

Todd, I'd recommend slow setting epoxy. It takes the stress out of the glue up and is very strong. You still get some springback but its not as bad as other adhesives.

[Leland Berry]

Outdoor Exposure ? Good advice here,but would the same apply for
outdoor furniture ? I'd like to find something other than the Gorilla Glue
I've used on glue-lam Eastern Red Cedar due to squeeze out etc. 8 -2" x
9/16 strips x 10ft strips clamped in an arched jig for stringers for Garden
bridges. I have < 1/8' springback, and they will split before the GG gives.
At center they are displaced from straight about 14 "and I haven't had a
failure in 3 years, but the stuff is nasty and requires lots of clean-up.
Any Ideas ? -- Thankx

[Richard Wolf]

I agree with Bob Smalser about the about of lams. If you could increase the number, your chances of spring back will decrease. I use Uni Bond 800 for all my laminated rails.

Richard

[Todd Bin]

There are two major advantages of the plastic resin glue.

1. You have a long time to get the laminates glued up in your form (30 to 45 minutes) comparted to 5 to 10 minutes with yellow glue.

2. The plastic resin glue is extremely hard and once dry is not sensitive to temperature so there will not be any springback.

For laminations plastic resin glue should be your only choice.

Note: The only drawback is that it takes 24 hours to fully cure.

[Todd Jensen]

Thanks for the reply Todd; I'm looking forward to trying it for the first time. I'd always had good luck with yellow glue, so am looking forward to the advantages of the plastic resin. Thanks again for all the input and replies -

Todd (J):)

[Mike Henderson]

2. The plastic resin glue is extremely hard and once dry is not sensitive to temperature so there will not be any springback.
Plastic resin is a good glue for laminate bending but you will still get springback. Springback is not dependent on the glue but on the number of laminations - the more laminations, the less springback.

Perhaps Todd Bin meant "creep" instead of "springback".

Mike

[Todd Jensen]

well, overall, this means suckage. I've got 9 ply, a mostly straight run, and a bend that goes from a straight 35 degrees to a bend and 45 degree rake. Fun! :D

[Cliff Rohrabacher]

If you can tolerate a purple joint, Formaldehyde glues are the SHIZ at resisting cold creep.

[Todd Bin]

It is my understanding that what people refer to as plastic resin glue is in fact urea formaldehyde glue. Plastic resin is just the generic term.

I was actually referring to spring back and cold creep in the same sentence. I have seen a demo where a person pours out some yellow glue onto glass and plastic resin glue onto glass and let both dry. He then held both dried pieces of glue in his hands for approximately 5 min and the yellow glue was very plyable. You could twist it into a pretzel but the plastic resin (urea formaldehyde) was very hard and brittle. So no creek with the plastic resin glue even if your furniture is placed in direct sunlight.

The laminations I have done have had 20 or so laminations and I had 0 detectable springback. I am not sure what whould happen with 9. But I can say that you will get less springback with a harder glue. So the plastic resin glue is still the best.

Here is a link to an article David Marks recently published on Plastic resin glues. Hope this helps.

http://www.djmarks.com/pdf/ureaglue.pdf

Thanks,

Todd

[Todd Jensen]

A new question... I cannot find any 'fresh' UF glue locally nor a local Unibond dealer. I am beginning to consider System 3 epoxy for this project because I would like to bend it this week and don't have time to wait for shipping of the above glues. I am looking for any advice/info from anyone(Justin?) that has used the System 3 for laminating handrail(or something similar). Thanks again for all the replies, and thanks for any more help.

[Jamie Buxton]

A new question... I cannot find any 'fresh' UF glue locally nor a local Unibond dealer. I am beginning to consider System 3 epoxy for this project because I would like to bend it this week and don't have time to wait for shipping of the above glues. I am looking for any advice/info from anyone(Justin?) that has used the System 3 for laminating handrail(or something similar). Thanks again for all the replies, and thanks for any more help.

Epoxy like System 3 is pretty straightforward. You measure the two components according to the mfg's instructions, mix them together, and away you go. Cleaning the resin off the measuring gear is nearly impossible. Use something disposable, like paper cups. Don't leave unused mixed epoxy in a styrofoam cup; it heats as it cures, and can melt the cup. DAMHIKT. For spreading over large areas, a disposable foam roller from a paint store is good.

[Todd Jensen]

Thanks Jamie. Will it dry as rigid as the plastic resin glues or unibond?

[Jamie Buxton]

Thanks Jamie. Will it dry as rigid as the plastic resin glues or unibond?


Yes. Epoxy and ureaformaldehyde are glues which don't have the creep which PVA is sometimes accused of having.

(Unibond 800 and DAP's Plastic Resin Glue are both ureaformaldehyde glues. PVA stands for polyvinylacetate, and is the common woodworker's glue. Elmers and Titebond are the common brands.)

[Todd Jensen]

Thanks Jamie. I'm going to give the epoxy a try and will update with how it works out for me.

[Todd Jensen]

Well, an update sort've. I talked to the rep from System Three Epoxies today, discussed my project, and he recommended T-88. He said use glue for gluing... ???:confused: I told him, well I'm laminating more than gluing and told him my specific purpose, but he still acted like I was foolish for considering their general purpose epoxy for such a purpose. Anyways, here is a link to their recommendations which contradicts what their tech-support guy told me(it says T-88 is not recommended for laminating)..: http://www.systemthree.com/members/literature/End_Use_Chart.pdf

Which supports what you told me Jamie and what I've read about guys using epoxies for laminations; I'm just surprised the System 3 tech guy acted the way he did about this application for their gp epoxy.
Rather than spend $125 on their products, I'm now going to just try some of this older plastic resin powder I've found, and will order some fresh stuff(unibond) for the next project.

[Todd Jensen]

Thought I'd post an update to my first Plastic Resin experience; thanks to all for your advice as it went better than I could have expected.

Here's a picture of the rail on the right which I re-clamped while it waits for the left rail to get finished(it is hanging out for a day or two getting comfy with its new positioning before laminating)

http://i191.photobucket.com/albums/z66/grizzified/OuterRailUplandProjectPreLam.jpg

And a close-up of the rail on the right to show its very limited springback:
http://i191.photobucket.com/albums/z66/grizzified/CloseupUplandProjectRightRailSpring.jpg

Its the least amount of springback I've had with a straight to curve type bend, and was the hardest wood I've bent with this type of bend. The plastic resin powder I used(Dap Weldwood) was well past its recommended one year shelf life but it mixed up lump-free, had great open time, and I'm very impressed with its adhesive qualities. It has to rival the epoxies for this type of usage at a fraction of the price. I literally had zero voids and practically invisible glue lines.

http://i191.photobucket.com/albums/z66/grizzified/UplandRightRailUtilityBladeScraperS.jpg

[John Lucas]

Todd,
real nice work. Just one thing for your info in future times: epoxy can clean up with white vinegar. Great for hands and things...not for other stuff...use disposable there.
Unbond 800 can be purchased directly from Vacuum Pressing Systems http://www.vacupress.com/vacuumveneering.htm. they are the importers of the stuff and it is great.