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Plastic resin glue11/21
Looking for an alternative to using plastic resin glue
I've got a job where it is specified, laminating two approximately 42" x 48" advantec (basically OSB subfloor) together, they need to stay flat so we are using a vacuum frame press.
I'm just wondering if there is an alternative adhesive that has similar properties but is a little more "user friendly" . Mixing the plastic resin glue, dealing with lumps, keeping the shop above 70, clamping for 10-13 hours, etc is becoming a pain especially when trying to 12 units at a time.
Thanks in advance
What's wrong with regular aliphatic resin which only requires 30 minutes of clamp time and 55 degrees? if you need more open time, then try the "extend" product or the weatherproof or waterproof varieties.
To my knowledge, only Recorcinal is rated as both structural and waterproof. It is easy to mix since there is no dry powder but does require a room temperature of 70 degrees.
Thanks for the response
For me it would be fine but I'm trying to satisfy and engineer that specd out the plastic resin. I don't think the water proof part is a big concern but the "stiffness" once it is set is a bigger concern
Just a thought: Get the shop up to temperature, Put a sheet of melamine cover sheet on a flat spot. Mix enough glue for the entire batch. If you don't have a glue roller just use 9" roller frames and get three guys to go like hell. Stack & pin all the parts and take the forklift and set a unit of any sort of board on it. Next morning it's done, saw to size, then you can lower the furnace. Just one other thought, OSB subfloor is sometimes treated with wax to resist moisture. Will that affect the glue line???
I would ask the engineer to specify the adhesive, prep work, and schedule, incase something goes wrong later on. From my experience trying to glue OSB with anything short of construction adhesive is sketchy at best due to the waxy coating. I have worked with advantech as well. Watch out for the slivers that like to come off of it into your hands while handling it.
Wax is indeed commonly added to the outside of the OSB fibers or strands. If you sand the surface just before gluing, you will expose wood that does not have wax, as the was is only on the outside of the strands. This sanding just before gluing will also increase the joint strength substantially compared to using an old surface.
I am assuming that by plastic resin glue, you are referring to urea formaldehyde (UF) adhesive, such as Weldwood by DAP. Are you certain that you want an adhesive with the "F" word? There are some good alternatives...ask your favorite adhesive manufacturer for a replacement formulation.
The construction adhesives will not develop the strength that is apparently needed. Has your engineer considered a our adhesive. Some oif these provide excellent strength. But, overall, I would consider an advanced formula PVA (such as TB II). Many adhesives will provide a joint stronger than the OSB itself.
The advantech does not seem to have any wax on the surface. I am planning on making up a panel with the Titebond 2 and have the engineer test it to compare it to the ones we have made so far with plastic resin glue
Thanks for the responses
A quick test to check on the glue-ability of a surface is to put a water droplet on the surface and then note if the droplet disperses in a minute or two or just sits there like a drop of water on a newly waxed car. The lack of dispersal can be from wax or from other causes.
Since you've mentioned that "stiffness" was a factor while "waterproof" was not, you might consider two test samples, one with T2 and the other with original Titebond.
The original stuff dries brittle, while T2 remains a bit gummy. Neither of these adhesives are structurally approved but both are stronger than the wood substrate.
epoxy, cold temp. hardener, stack full 4x8 sheets, 6 pairs of sheets at a time on top of each other. Cut the panels in half after the cure. Keep the resin and hardener in a warming box to accelerate the cure.
Engineers all love epoxy.
Be careful with epoxy. It requires a thick joint, so do not use too much pressure. On OSB your spread rate would be high so it would be very expensive.
In my past tests of various glues, epoxy had more creep under continuous stress that any other.
PVAs like TB will creep much more than epoxy.
I wonder where our tests went wrong. Here's what we did: Material hard maple, 1/4" thick, laminated and clamped over a form for rocking chair rockers. Legs were mortised in. The rockers had a slight re-curve designed into the back as a stop.
Disclaimer, this was done w/o scientific controls for actual glue thickness and times. Clamping was manual so it varied some. Glued wide enough to be ripped into two rockers. Times were all about the same. The same M/F form was used for all. By the time 6 layers were pulled in all at the same time there was a lot of pressure.
Conclusion: make the rockers a little deeper to offset the short grain issue and saw/route from solid stock. If rockers aren't exactly the same curve the chair will walk sideways.
My first guess is that the epoxy glue line was too thin.
I do believe that we may have a different definition of creep. Creep is the long term (months and years) of deformation (or slipping) of a glue joint. It is not short term unless the glue itself never hardens such as with construction adhesives or rubber glues.
Perhaps you can define your use of the word...as you seem to relate it to machining failure, perhaps you are thinking of strength. Strength of an epoxy glue line is quite low if the pressure is too high resulting in a thin glue line...thin (0.002 to 0.006") is fine for pva adhesives like TB or white glue.
Our time frame was a month or so to compare the parts to the original form. My comment about machining related to the failure of the urea F. glue. It was the only one that had a problem. Like I said it was probably the result of poor gluing practice. The moisture wicked away quicker than we got it fully clamped would be my guess. By then the glue wouldn't have squeezed down the appropriate thickness. Parts were hand glued as opposed to a glue spreader. A Maka mortiser was used and they are pretty "violent" in their operation. You are also probably right about too thin of a glue line on the epoxy since all glues were taken to about the same pressure. When the strips were forced down into the mold there would have been a wiping action at either end. At any rate the test was still valid for this particular application.
Are you seriously questioning the structural properties of epoxy resin? Apparently any boat(or airplane) built in the last 40 years is dangerous.
The bond/shear strength is a non issue. I proposed it for your "other" reasons.
If you Google "epoxy boat failure" you will find many times when an epoxy joint failed under load. When properly made, an epoxy joint is very strong--stronger than the wood. However, it is easy to make a poor joint by using too much pressure (if a tight clamp is good, a tighter clamp is even better) and getting a thin joint with not enough epoxy to do the job. Epoxy needs a thick glue line, compared to most other adhesives, if a strong joint is desired.
The only reason a woodworker should ever have for using epoxy as an adhesive is when adequate clamping is not possible. This is the only reason why boat and airplane builders use this stuff. Epoxy resin is the only glue to use for cold-molded construction. It also excels as a sheathing substance when applied over fiberglass or Kevlar mat.
Epoxy is neither approved or rated as a "structural wood adhesive" for any kind of building construction. To my knowledge, only resorcinal is structurally approved for glue-lam beams and plywood fabrication. Clamping requirements are also specified.
The price of epoxy should be reason enough to discourage any woodworker from its' casual usage. A properly prepared and clamped joint using almost any kind of traditional woodworking glue, is still the way to go. Epoxy should generally be left on the shelf (but not for to long).
Well said Jim. I agree with your comments. Also, the procedure mentioned earlier for using the UF resin should work fine. It's likely that a PVA would be just fine for this application but the UF would certainly provide more rigidity.