I just refinished some hardwood floors for the first time, and when I put on the second coat of polyurethane after screeding the first coat, there still seems to be little bubbles from when it dried. I used Parks Oil based Modified Polyurethane, which was High gloss. I used a lambs wool applicator to apply the finish. I do remember reading some where in a Wood working magazine too cut the urethane with paint thinnner or mineral spirts. I was wondering if any you had any suggestions.
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what was installation temperature?
I had this problem with an epoxy cover and it was cause by the roller nap being too tall. trapping air.
I had this same problem using lambs wool as a applicator. What I did was use a roller and tipped it off with a wide brush. Came out alot nicer.
Darkworksite4:
El americano pasado hacia fuera ase la bandera
The installation temperature was between 70- 75 degrees.
"when I put on the second coat of polyurethane after screeding the first coat, there still seems to be little bubbles from when it dried"
DANA,
You didn't state what type of wood flooring it was, but if it was a coarse grain wood, something like oak, as the finish slowly penetrates the pores, it displaces the air in the pores, causeing the air to rise to the surface of the finish. If the finish has already begun to cure, the bubbles won't break and flow out.
Jon
Edited 4/13/2004 9:54 am ET by WorkshopJon
It was oak and a very open grain flooring.
I was wondering should i screed it and apply another coat to eliminate the little bubbles.
"I was wondering should i screed it and apply another coat to eliminate the little bubbles"
Dana,
All I can tell you, since I've never used the product you have used, is that due to Federal regulations, many products have had the levels of VOC's reduced in the past few years, and they are also required by law to tell you not to thin them out.
If it where me, and the finish appeared to thick, then yes, I'd sand down the finish, and lay down another coat, after adjusting its viscosity with the appropriate solvent.
Jon
I've found by blowing across the surface of the already applied surface (after you see bubbles form) they break and smooth real fast.
But I also think you may be applying too heavy. But I'm no expert.
Poly is best stirred, not shaken. I think theres a warning on the label.
I know that on my fir floor Ditch recommended a coating of sanding sealer before I put down the first layer of polyurethane.
Are the bubbles consistently in one location, such as near a wall where the applicator was pulled off the floor? I modified my technique so that I always went back over an area where the applicator had been pulled up since that seemed to leave bubbles
The bubbles are consistently through out the floor but a little more pronounced toward the walls. i think i should of used the sanding sealer, i agree with that statement. Would a foam roller work better then the lambs wool applicator.
be carefull mixing you can trap a lot of bubbles that way never shake poly.
it helps if you cut polyuethane with a little mineral spirits it will be easier to work with and self level as it dries.if you have a bad case of bubbles you will have to let it cure up before you can sand it off and you might get lucky. sometimes bubbles disapear when the floor cures. if you dont let it cure enought before sanding it will just clog the sandpaper. so maybe just wait a couple of days and see what happens. but dont apply more over the top of the bad stuff it wont fill in and will just be more work to get off
When I've gotten bubbles, it is due to working it with the brush/roller to much, using a fuzzy roller with too much fuzzy (foam rollers sometimes work well), or working in a rising temperature.
A rising temp causes air in the wood to expand out into the finish. A falling temp causes that air to contract and avoids bubbles.
Like JetBoy said, did you use a Sanding Sealer? They sell it by the gallon in the flooring section. I had a similar experience with real unfinished local Maple on my test strips.
Real as opposed to fake maple?