Poly won't cure - Woodworking Talk

Ken Johnson · 09-13-2008, 09:34 PM

I am in the process of finishing the exterior of a cigar humidor with Minwax oil-based quick drying Polyurethane. It has been about three days since I applied the first coat. It is completely cured on the spalted poplar top and the sapele sides. The handles however are mase of padauk and are still tacky to the touch. The sapele and spalted poplar are not as dense and soaked up the poly. The dense padauk did not allow the poly to soak in. Do I just need to wait longer or do I need to do something to fix this?

cabinetman · 09-13-2008, 11:49 PM

If it was all done with the same batch, and other parts have dried give it more time. Oil base poly will dry applied to even a non porous surface given time. If the tacky section was from a different container, it could be contaminated or just old. It might be possible the wood had some foreign material or was treated with some chemical, or something that may have reacted with the finish. If you applied an oil first it may inhibit the drying time, but it should still cure.

Tweegs · 09-14-2008, 09:09 AM

Do what Cabinetman suggests. If it still remains tacky after a few more days, you may need to remove the poly on the padauk, wipe it down with acetone and reapply the poly. As Cabinetman said, there may be a contaminate/chemical/oil on the wood that is reacting with the finish. The acetone should remove it.

For future reference, the acetone is almost a must when finishing oily woods like Teak and Rosewood.

Ken Johnson · 09-14-2008, 09:13 AM

It is definately getting less tacky as the days pass. I just never expected that it would take so long. All the pieces were done at the same time with the same batch of poly. Next tim should I wipe down with acetone before finishing it?

jerry · 09-14-2008, 11:48 AM

Next time try something other than polyurethane varnish.

Jerry
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Ken Johnson · 09-14-2008, 06:22 PM

Such as..........???

Tweegs · 09-15-2008, 08:27 AM

Quote:

Originally Posted by Ken Johnson

It is definately getting less tacky as the days pass. I just never expected that it would take so long. All the pieces were done at the same time with the same batch of poly. Next tim should I wipe down with acetone before finishing it?

You could, but it's not always necessary. Oak, walnut, maple, cherry, ash, pine, poplar and hickory (the more common woods we use) don't need it, they aren't oily. Some of the exotics like teak and rosewood are oily and it is best to use the acetone prior to the stain and/or finish. Good idea to wipe down any joints prior to gluing with these woods too.

I've never used padauk, don't know if it is oily or not, but at least in your case it has all the symtoms. Could have just been some other contaminate as well, hard telling.