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Thinning Titebond II for slower set5/24
I read that Titebond can be thinned 5% without diminishing it's holding strength. With 100+ temperatures coming and 8% humidity we need a longer open time for large table top glue-ups. I have considered the Titebond Extend but it's a little more expensive.
Consider wetting the wood surfaces that will be glued with a damp (not soaking wet) rag just prior to spreading the adhesive. Also consider keeping the adhesive in a refrigerator kept at 70 F. These both should give you extended time.
Are you seriously concerned about spending an extra $5 or so per gallon for slower setting glue?. If so, then follow the Dr's advice, but you might want to rethink your pricing strategy to allow for using the optimal materials for the jobs at hand. Epoxy and plastic resin glues will give you far more assembly time at greater but scarcely prohibitive cost.
The adhesiveness of the glue is not really the issue. It is probably good enough. It is common to water down PVA for glue sizing.
The bigger concern would be increasing the potential for starved joints. The thinner glue may squeeze out of the joint or the wood fibers may absorb the excess water. No one knows.
Why risk it when you can simply buy the Extend version and sleep at night.
Pay the extra few $ per gallon and get a pva with extended open time. Adhesives are not a place to be "cheap" and handyman tricks have no place in professional work.
I would not take any chances. Diluting the glue with water may not even have the desired effect. It could even speed up the dry time. You would certainly change the viscosity.
Diluting PVA as glue size certainly works, however we do not use glue size to "glue parts together" so this does not provide a reliable indication on affects this dilution may have on adhesion.
If you add water you are effectively changing the formulation of the adhesive. Without a background as chemical engineer with experience developing adhesives, and knowledge
As a professional woodworker you should 1. choose an adhesive that has the desired working properties, and open time. 2 use this product within recommended application following the manufactures prescribed guidelines for use.
"Most of our wood glues can be thinned with water up to 5% by weight or volume. Adding more than 5% water to our glues could negatively affect the bond strength. Titebond Polyurethane and Titebond Liquid Hide Glues can be thinned by carefully heating the bottle in a pan of warm water."
The manufacturer does NOT state that thinning will change the open time or change the curing time however.
As Adam states, a warm adhesive which thins it and a water thinned adhesive lead easily to a starved joint.
I have thinned titebond for years when making bending rails, so that the material can be brushed on easier. I have never had a problem with the bond and if you were going to have a problem it would certainly be there being that rails with a tighter radius are under extreme pressure.
Elmer's white wood glue has decent open time. I used it for several years and it's cheap. Just like all modern PVA glues, it's stronger than the wood.
Now I'm using Titebond 2 Extend because it can be cured with a hot press. Its open time for normal work is ok but I think the Elmer's was longer.
You might try a little bottle of Elmer's.
Though I've often dampened wood to increase open time on a joint, I've been told it's not a good idea.
The theory is that the glue relies on penetration, even if it's only a few thousandths' worth. If the wood has been wetted, the cells are fuller, leading to less penetration.
I'm not saying I buy it, but a glue supplier told me so I keep wondering if it's true.
Let me explain...wetting a joint does increase the surface MC (but not so much that the cells are full). The wetter surface with PVA adhesives (but not pur) means that the moisture in the glue will leave the adhesive more slowly. The adhesive joint cures by moisture loss, so this means slower curing.
But the real issue is that with very dry wood without wetting, the moisture will be "sucked out of the adhesive really fast and then the adhesive will be thick and will also start curing before the pressure is applied and will not flow well into the nooks and crannies, etc.
Thanks, Gene. That makes a lot more sense.