Polyurethane finish pitted and streaky

[smannixs]

Hey there,

Newbie here. I'm trying to refinish a water stained coffee table. I removed the old varnish, sanded and restained the top using miniwax. I was very happy with it until I went to put on polyurethane. I applied Varathane oil-based semi-gloss with a white china bristle brush. After 9 hours, the first coat came out a bit clumpy and pitted but I wasn't sure if that was normal for a first coat. I sanded it down (220) and applied a second coat with similar results.

A few questions:

1) Is this fixable with mineral spirits? Should I just keep sanding and reapplying more coats?
2) Any ideas what I might be doing wrong?
3) Can I still salvage this project without completely stripping and starting again?

I've attached some photos of the pitting. Any help would be appreciated.

THanks!

[spectre]

Erm well... I'm guessing.... minwax lives up to its name and contains wax... and you've put a solvent based poly over it, meaning the wax is interfereing with the poly, and as its still cissing on the surface, looks like its floating throught successive coats.

I don't know about the long term viability of your surface. It would have been best to seal your minwax with something like shellac prior to the poly. I'd probably be inclined to sand the living daylights out of it just to get it flat, still put a coat of shellac on it, and refinish with the poly.

[Honorary Bloke]

Sorry Spectre, me old China, no wax in that stain, although it sounds as though it might have it. One can apply oil-based poly over Minwax stain with impunity. But there might be more than stain involved, like silica or the old finish.

What appears to me to be the most likely culprit here is that the poly has been applied too thickly or has been applied before the stain has dried sufficiently (at least 24 hours). It is also possible that, although you believe you removed the old varnish, you really did not quite get it all. Spectre's shellac sealer idea is quite sound.

Poly problems can never be cured with mineral spirits once dry. But thinning the poly with spirits may help it lay down more evenly (and think thin coats, it isn't paint).

Can you salvage the project? No, sorry. Sand back and go again. :(