I've got a spiral handrail to do. I've done curved okay, but I don't think I'd have enough time to do the glue-up and clamp in enough time with ole yellow. Is there a slower setting (open time) glue that is as good as yellow glue? It's only me and my partner and time would be an issue. Thanks in advance - your knowledge is always helpful.
(Architectural Woodworking Forum)
From contributor C:
This is where you show your stuff. A good dry fit, and marking all the pieces so they can be picked up and put into the glueup fast is helpful. Extend Titebond glue is also helpful, and running back and re-hitting anything that's drying too fast. Both guys should have glue rollers and plenty of tape and rags. It's a good time to hustle, and it takes a lot of clamps - the more, the better. Clamp it into place as fast as possible and then use damp rags and wipe off the excess as much as possible - it's very helpful for the sanding. Finely scrape to clean up excess dried glue, etc.
TB Extend is good if you don't waste your time and get to it. Takes about 10 minutes to get it on the rack to the point where you can start clamping in between the first and last clamp. It also helps if you dry bend the entire thing a day or two before. The wood will take a partial set, making it easier to rebend.
I glue both sides of all laminations and when stacked hold them together with nylon zip ties. Just one at each end and one in the middle. Not too tight. The wood needs to slide as it is being bent. The hardest thing about bending spiral/helical/curved rail is the twist that needs to be applied to keep the bottom of the rail flat.
There's a good reason why they don't use yellow glue for glue lam beams holding up a roof.
The following is a quote from the Titebond.com website:
"Polyvinyl Acetate (PVA) Glue: Any glue consisting primarily of polyvinyl acetate polymer. This category includes most traditional white glues and more advanced yellow aliphatic resin glues. Although PVA glues can vary in strength, flexibility, water-resistance and sandability, they offer good performance, cleanup with water and are non-toxic. Because PVA glues tend to “creep”, or slowly stretch under long-term loads, they are not recommended for structural applications."
Glue creep is not a myth. In the context of this discussion, I'll define it as the tendency for a tightly bent handrail to try to straighten out by stretching the fully cured glue. The operative word from the above quote is "slowly."
PVA glues, even when fully cured, remain relatively soft and flexible compared with plastic resin. That's what makes them tough. That's what makes them creep. Glues like plastic resin, when cured, are hard as glass.
Zip strips! Should have thought of that.
Have you ever tried four inch shrink wrap, wrapped tightly around the whole bundle before bending? Someone once told me that that was a sweet secret.
Have you ever tried to bend a rail up the stair and around 180 degrees and made it work? Have you ever discovered finger joints in your bending-rail while trying to bend it? Is there such a thing as too many clamps?
Yes, I've done at least a couple of 180 degree bends. They work fine.
Yes, about 20 years ago when some genius decided to finger joint bending rail, I ordered a bunch of 6010 16 footers without finger joints. Still have some of it if anyone's interested.
I bought enough clamps to bend two long rails at the same time. Now I have enough of them to actually bend one at a time.
We always use epoxy for projects like handrails, mostly because of extended dry times. Never used the plastic resin (Weldwood?) for anything. I don't consider a handrail in the same category as a structural beam, so I wouldn't hesitate to use regular wood glues if the dry time permits.
I'm thinking that you used white glue way back when you had your paradigm shift. That stuff creeps big time. The absolute hardness of the resin glues can give you a telegraph, as well, when painting.
So, maybe the plastic resin would be a better adhesive to use.