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Need to find non-UF Glue for bent laminations10/16
I've been using Unibond 800 for years on bent laminations...most are gentle curves, min radius 6 - 15 meter.
-piano soundboard ribs, 8 to10 x 1/8" laminations in sitka
The UF glues have always bothered my breathing....its gotten worse, so I need to jump ship on the UF's entirely.
So, in reading through the knowledge based info, it seems low creep options might be Titebond Extend or Extend II. Any experience with spring back and length of time needed in the press on these glues?
Other options?...I use epoxy, but for this its way overkill. Readily available small shop Polyurethanes like Gorilla, have worked for me well on face laminations. Easy machining, no spring back at these radii...but spreading many laminations without the advantages of a spreader of some sort makes the gorilla type polys too hard/slow to apply. Any ways to roll gorilla type glues on face lams
My understanding is that springback is determined by number and thickness of laminations and the tensile strength of the material as well as the radius of bend. Short of glue line failure, your choice of adhesive is not a factor. I have glued many bent lams with Titebond 2 and haven't had issues. In the summer I would have preferred to have longer open time but I overcame skinning of the glue by spreading more. Messy insurance. Springback was predictable and small. I would recommend full 12-24 hour cure on the form or drying fixture but you would be doing this with any glue.
talked to both Titebond tech,and Daryl @ vacupress re Unibond 1. Titebond extend has the hardest glue line of the Titebond line, and Unibond 1 was formulated to that same hard(relatively speaking) Extend PVA glue line + a blocker for veneering.
I decided to try the Unibond 1as it has the extend glue line and also can be tinted as per the wood color.
Bent lamination clamp times have been at least 12 hr with the UF. I will give the PVA a full 24 hour, and/or set up a resting caul, where laminations can be taken out of the form after 24 hrs, and clamped very minimally (just to hold the existing shape) in the form as they cure for a few days.
You mention Unibond. Are you thinking about Unibond 800? This is a UF adhesive...urea formaldehyde. Actually Unbind makes a whole lot of adhesives, so some additional specification would be helpful.
When using any adhesive with "F", you probably want to use very good ventilation, due to the carcinogenic effect.
When you mention gorilla glue, that is one specific type of polyurethane adhesive. There are many different ones with different spread requirements, curing times, and so on. You should explore these adhesives because they are excellent and have no "F".
Even some PVA adhesives have "F" in order to help curing. Check the on-line Consumer Info Sheets and you may be surprised...a small amount of "F" but it is there.
Are there Polyurethanes available in small shop quantities...ie a couple of quarts or a gallon at a time? Last time I tried to research this, commercial Polyurethanes seem to only be available in rather large quantities.For this reason, I haven't looked too far into the other PU formulations and mostly stick with Gorilla PU glue...Gorilla PU is available in small shop, small run quantities.
Am I missing out on other small quantity PU supply options?
PUR also does not have any moisture, which be a help sometimes. However some PUR adhesives are not as rigid, which can be an issue.