Polyurethane problem

[Brian Siano]

I'm refinishing some drawers, and the first coat of poly doesn't seem to be drying properly. While some surfaces are nice, hard and smooth, others are still tacky three days after application, and in other areas, the poly seems to have seeped into the wood leaving the surface, well, almost untouched. (Okay, I did dilute the stuff pretty severely with paint thinner.)

The thing is, those surfaces which are still tacky... I'd like to know what might be causing this. (It could be that my basement shop is too humid. This has been a record-breaking week for this in my area.) I'd like to know if I should just try a new coat of less-silute poly over it, or if I should strip it off and start over.

By the way, the project with photos can be seen at

It's the Chest of Drawers project.

[J. Clarke]

Why are you thinning it at all? Polyurethane generally isn't happy when thinned before brush or roller application--it won't level properly.

As to why it's not drying, it could be something in the wood--I've noticed that some species for some reason seem to inhibit the curing of polyurethane--it should get there eventually and when it does sand it smooth and put on another coat. If you strip it off, then try a coat of dewaxed shellac before the polyurethane when you recoat--it should act as a barrier coat and keep whatever in the wood is preventing cure of the polyurethane from having an effect.

[Patriarch]

"J. Clarke" wrote in news: [e-mail]:

Jumping in here, sorry... I must have missed the first post...

Sometimes, various types of 'cedar' aromatics can cause this gummy, non- drying symptom. One of my early projects, a tresure box for one of my sons, had a similar symptom. Checking your web page, it seems _possible_ that there is some cedar type wood in the project.

If you can, move the parts to a well-ventilated area, and see if the poly will cure. Otherwise, it may be a removal challenge...

Good luck!

Patriarch

[Peter Huebner]

My wife's had problems with oil based poly on stripped old drawers once or twice - presumably some left over Ancient Varnish from the 30ies or 50ies, who knows, interfering with the curing process. A moisture curing poly might do better (that *thrives* on humid conditions).

Severely thinning is not recommended. First coat of poly on chipboard flooring, ok - about 10% from memory. But other than that, I wouldn't. If I want to use a base coat under poly, I'd use a teak-oil like concoction (mix my own) but not use overly thinned poly.

f.w.i.w.

-P.

[gfretwell]

That was my question ... what is under the tacky poly? Same as good stuff?

[Brian Siano]

I'm pretty sure it's not cedar, but some kind of pine for the sides of the drawers. The drawer _bottom_ seems to be mahoghany or a veneer.

But I think I've found a solution. I did another coat of less-diluted poly over the troublesome spots, and with a fan going to circulate the air, it seems to be doing OK. I'll probably sand it down and do another coat later this week.

As far as stripping it goes, methylene chloride can probably do the job. But I'm okay with sanding it down for smoothness,