Wood Refinishing Question

Cindy in NY · #1 07/27/12, 07:02 PM

Here's a question from DH:

We're refinishing some 100 yr old wood stairs that had stain and shellac. After sanding the stairs to bare wood, 2- 3 coats of natural stain was applied. When we applied the 1st coat of polyurethane -- within minutes a white film appeared on the wood as the polyurethane began to dry. The film dries hard and must be sanded to be removed. Scuffing with scotchbrite, or applying more polyurethane doesn't help.

Any ideas?

bignugly · #2 07/27/12, 08:07 PM

Quote:

Originally Posted by Cindy in NY

Here's a question from DH:

We're refinishing some 100 yr old wood stairs that had stain and shellac. After sanding the stairs to bare wood, 2- 3 coats of natural stain was applied. When we applied the 1st coat of polyurethane -- within minutes a white film appeared on the wood as the polyurethane began to dry. The film dries hard and must be sanded to be removed. Scuffing with scotchbrite, or applying more polyurethane doesn't help.

Any ideas?

Sounds like you night have used an oil based stain and a water based polyurethane. That may have caused the problem. Only solution I know of is to re-sand and start over

nc_mtn · #3 07/27/12, 08:19 PM

Yep. No real need to apply natural stain IMO. If you want to use H2O finish, just use a de-natured alcohol based finish. Get a "Universal Sealer" (Bulls Eye brand) and then in about 30 min or less you can coat over with another finish Water or Oil. Get a good quality finish since you have to resand anyway. That stuff you get at Lowes won't hold up as good as others. If you go a big box store, get the Parks brand OMU. I think for the cheap stuff thats about as good as you can get. You'd be best to find a flooring store and buy a gallon. Well worth it. Much better stuff. Both H2O and OMU. I wouldn't put the cheap H2O stuff on my dog house floor if you gave it to me. It won't hold up worth anything, much less the abuse a stair gets

VinnyP · #4 07/27/12, 10:04 PM

Sounds like a moisture issue. Stain may not have dried completely or the relative humidity may be too high.

nc_mtn · #5 07/27/12, 10:12 PM

You're probably partly right Vinny but, if it was both oil based stain (like most any commonly used stain) and Oil based (OMU) poly then it wouldn't turn white. The same applies to H2O stain/finish combo. I'm betting on oil stain and H2O finish. Oil Stain takes at LEAST 24 hours to properly dry before H2O put on.
BTW, if you ever wanted to put H2O finish over an OMU then you should wait 21 days. Most are still technically offgassing for that long.

nc_mtn · #6 07/27/12, 10:23 PM

I just was thinking about shellac being used. It could have the same affect at the H2O because the base (possibly de-natured alcohol).
The key, is still the same, if in a hurry use the same based products.
But I also know that "shellac" "varnish" and "polyurethane" are all different products BUT the names are often used interchangeably among "common" people.

VinnyP · #7 07/27/12, 10:32 PM

In NY you can't buy oil based stain in containers larger than a quart (due to VOCs). I guess I assumed (you know what happens when you do that) that the stain was water-based.

Would probably be beneficial if we knew what products were used.

nc_mtn · #8 07/29/12, 04:44 PM

I had forgotten the VOC deal with NY. Guess it's working it's way around the US. I think it's crap myself. I haven't had any luck with Water Based Stain. It looks too "milky" to me. Which could be part of the problem. Just like I said with H2O over OMU, you gotta wait (according to most manufactures) like 7 days I think to put Oil over H2O