bobcat,

What stain did you use on this floor? How long did the stain dry before your first coat of finish?

There are several things that can cause bubbles in the finish. Stain that has not dried before the first coat of finish can cause bubbles. The stain may feel dry on the surface but still be wet below the surface causing the finish to bubble.

Some brands of finish are known to bubble more than other brands. It could even be your application method causing the problem.

Edgerboy,
Thanks. I suspect that the stain was not completely dry...that was my first thought when I saw this. You verified my suspicion. We were told to use rollers on the application by a local floor guy, however, we paint-brushed the edges and corners. What is the best way to apply poly? Is our only solution to strip, resand and restain?

Did you shake the can of poly to mix it up good

Hi floorguy:
Yes, we shook up the can of poly well. All I can think is that the bubbles and grainy effect are the result of not waiting long enough for the stain to thoroughly dry before applying the poly and, perhaps, the poly application technique. I hate to go any further on the floor, as I'm afraid we're just adding to the cost of correcting our mistakes. Fortunately, we've only done the living room. We have over 1400 sq ft on the 1st floor alone to refinish. I have a "professional refinisher" coming in next week to look at what we've done. He's already told me via phone that he'll definitely have to start completely over...meaning resanding down to the bare wood. Yikes. But the pecan floors are gorgeous so it's worth the cost, assuming it's done correctly. I keep reading horror stories on this forum about so-called "pros" really messing up a refinish job.

Next time, don't shake the can!!!!!!!!!!!!

See how I tricked you into telling me that little piece of information!!! It is the CSI inspector in me!!

Never shake the can of poly! Always stir really good by hand.

Shaking suspends air in the poly.

Floorguy:
Yes your joke was certainly entertaining. We did shake the can I suspect, which probably did contribute to this issue. We are DIY'ers so we certainly don't claim to be experts. Anyway, for any true experts out there, is there anything that can be done to bubbles in the poly other than starting over by sanding down to the wood again? We talked to HD folks and saw a Mimwax rep there. Explained the issue with the over-glossy look and he said that could be changed by applying a "toner" which roughs up the existing poly layer and then apply a satin layer. Don't think that would alleviate the bubbles and grainy effect???

Hi, I have no advice for you, unfortunately, but I'm in a similar situation except that I paid someone to refinish my floors and they were covered in pits from air bubbles and grit. My refinisher came in and put another coat of poly down without sanding it down to the wood. It looks better, but still not the way it should. I hope you get your answer.

Thanks, scramla. When we saw the bubbles after we applied our 1st coat, I was hoping a second coat might alleviate the problem. It didn't. A professional refinisher is coming in next week to look at things. Without seeing the floors, he's already told me he'll have to resand down to the bare wood and start completely over. Of course, he also wants the business and my $$. Are you going to do anthing else to your floors? Thanks again.

Floorguy did trick you and i realize you are a DIY'er but every can has instructions - do not shake, stir slowly to keep from forming air bubbles. I don't thing high gloss even needs stirring, just the satins or semi-glosses. It's going to have to be sanded off now.

You did do right by applying the first coats in a gloss, you then cut the final wear coat to whatever sheen you desire.

Was the stain thoroughly dry before applying the poly?

"Without seeing the floors, he's already told me he'll have to resand down to the bare wood and start completely over. Of course, he also wants the business and my $$."

He wants your business, but he also needs to be able to warranty his work. In order to warranty your floor and his work, he has got to go back to bare wood. What would happen if he comes and screens it and recoats over your work and then the finish you applied peels, causing his work to be messed up?

Would you hold him responsible to fix it on his dime??

Hi , More info from a contractor,i have seen this before, and sometimes the cause is fron usin g a roller,and it impregnates the urethane by lifting the liquid and mixing air to the mix then laying it back down, once it is rolled or foam pad applied it should be brushed slowly to smear,spread, and omiting the suspended air trapped in the poly coat ( Usually ) then washing it letting it dry lightly wipe with paint thinner,never use tac clothes

J R

Hey there , I'm having the same problem with my floors this is the second attempt of refinishing our wood floors, we went straight to bare wood twice since the first time we sanded they did a horrible job and the stain showed all the imperfections, now we have all these bubbles and rough spots on the floor after applying the clear semi gloss. How did you end up fixing you floors? msubobcat did u have to go back to bare wood or was something else done?

It's not uncommon to get bubbles in your first coat. You can sometimes thin the first coat a bit. But often it's simply easier to expect there will be bubbles, and accept them.

When you scuff or screen after the first coat has cured, the second will go on better than the first as the first coat will have sealed the bare wood and smoothed the surface a bit. Less texture, fewer open wood pores, means less entrained air.

Operator error. It's been mentioned already, but overworking the poly can lead to you entraining air as you roll back and forth. I'd ditch the roller. Use a brush to cut in and a pad for the open floor. You'll stand a better chance with a wool applicator pad (wool for oil, synthetic wool for water-based). Brushes, use a china bristle for oil, synthetic brush for water).

Get it on the floor, use the pad to gently spread it, then move on. Again, don't overwork it.

Oil has a longer working time. But again, get it down and leave it to settle.

You can always use a 4" brush and do the entire floor by hand. Again, don't overwork the poly in the can, or on the floor. By "in the can" I mean dip the brush and to remove excess, touch the brush to the side of the can instead of wiping it on the lip of the can. Wiping can entrain air.

Sand lightly between coats, vacuum and tack to get the dust up.

Your last coat if satin will look "satin".

PS: I'm not primarily a floor guy. I've done them, but it's not my specialty. If they haven't already, I'm sure more experienced folk will post.

I also have refinished an oak floor by staining, then applying oil based poly. The initial dry finish was fairly good; however after a couple of weeks/months, beads of poly began to form on the cracks between the floor boards. Some pin-head sized, others larger. I can remove most with an angled razor blade with no marring. The larger beads leave a noticeable blemish. Would this have been from the stain not being fully cured/dried prior to applying the poly?

Also, can I get a good finish by screening this floor and applying another top coat? (I may try the method of warming the poly before applying). Thanks for you advice.

I just polyed my new oak door skin using a sanding sealer first, then a pretty wet coat by roller. I noticed a few bubbles where the oak was grainy, easily fixed by sanding down with 400. Next coat I really laid it on heavy, result is lots of bubbles in those grainy areas again. Maybe too heavy of a coat, or is it the cheap Menards piece of oak veneer plywood that you can almost see through? Never had this happen before.

I sealed first, then my first coat looked pretty good, but my 2nd coat of poly bubbled. I put it on after 4 hours (per instructions on the can.. if you do it between 3 to 12 hours you don't sand between coats). However, I'm thinking maybe it wasn't dry enough. Anyway, my question is ... when sanding out the bubbles, do I have to sand down till there's no evidence of them, or just sand the tops off, and there will still be tiny white circles where the bubbles were, and the next coat will fill in.
Also, it seemed impossible to sand them with 220 or even 120. I had to use a 60 or 80. So now I'm afraid I've sanded too much, unless I sand the whole floor down to bare again. How smooth does this bumpy stuff I sanded the bubble off of have to be before I can spread another layer successfully? (This time I will avoid air, use less strokes, thin the stuff a little, and use a thinner layer.)

Great question. My refinisher rolled the poly on with a paint roller for 2 coats, and there are gritty bits in the surface. Can I buff these out? If @Lionhouse007 couldn't get them out with 220 or 120, I doubt buffing will help... I'll try the 400 sandpaper that @Deanjanhauser mentioned...

Not all polyurethanes can be "rolled" on. The reason: air bubbles = bubbles in the finish. The HIGH END products (ahem....$150+ per gallon stuff) will have "anti-frothing" additives used to prevent this from happening. The rest....not so much.

The finish itself will tell you how to apply. They will LIST rollers as options. If they are NOT LISTED...they are not allowed. Once bubbles are in the finish, you need to sand down PAST the bubble layer and start again.

Sorry but this is an issue with failure to read the installation instructions. Not all finishes are allowed to use rollers. In fact most do NOT allow rollers (lambs wool applicators or T-bar applicators being the most common "requirements" for finishes).

Example: Loba ($150+ per gallon for most products) = anti-frothing properties = allows rollers (in fact they PREFER rollers).

Varathane: $60 - $80/gallon = no anti-frothing properties (no expensive additives) = rollers guarantee bubbles will occur.

NEVER EVER shake stains as it creates bubbles. Not fatal but an enormous painful and time consuming pain to rectify. Paints you shake, stains you don't!