Polyurethane too thick in a few areas

Q: I recently tried my hand at finishing my new floor with Fabulon finish, with lambswool. My problem is I applied the polyurethane too thick in a few areas. It took 36 hours for parts of the floor to dry to the touch. I sanded the floor heavily with 220 grit paper and noticed a few spots that are soft and can be pushed with your finger.

Will the floor ever harden completely? I am planning on sanding the floor each day to dry and cut down the amount of finish on the floor. Any other recommendations on what to do to buff down this thick poly? Thank you very much for your time.

A: You will likely have to wait at least 3 weeks before you can really buff this down. Apply fresh air and make sure it isn’t cold in the room. The only other thing you can do, provided we are only talking about a small spot, is to hand scrape most of it off and then buff it with fine sandpaper. Most finishes recommend a spread rate of 500 feet per gallon, which means putting some pressure on the applicator on the back stroke.

Similar Q: I just finished applying 3 coats of Basic Coatings Emulsion Pro Satin on my new Douglas Fir floors. There are obvious shiny, smooth spots on the floor now that it’s dry. I can tell they are thick spots where I must not have run the finish out as smooth as I should have. I used a Padco T-Bar applicator but the spots showed up after the finish leveled out. What can you suggest I do to fix the problem areas? Thanks in advance for all your help.

A: It sounds like the flattener in the finish didn’t have time to sink to the bottom of the film before it set up. I haven’t worked with Basic Coatings products in years. If I was you I would give them a call and talk to someone in tech. Unless they have changed as a company, they should be happy to help. I think you are probably going to have to buff and re-coat this.

Related Q: I applied a second coat with a paint brush and I think it was applied too thick. Now it doesn’t shine. Any way to fix this problem without starting over by sanding the floor down to bare wood again?

A: How thick the finish is applied has no effect on how shiny it is when it dries. It does however affect how soon it will dry and more importantly, how long it will take to cure. The shine of the coating is determined by the amount of silica paste added to the can to lessen how shiny it is. So there is hi gloss, gloss, semi gloss, satin, matte and super matte. If your finish is not shiny, perhaps you aren’t using gloss but maybe satin or semi? If you don’t like how it looks you can, when it is fully dry, lightly but thoroughly sand the finish surface with fine sandpaper, such as 120 grit or finer. This thorough scratching or scuffing is what the next coat will adhere to. Clean up the dust well and apply. Typically the spread rate is 500 sq feet per gallon. Thin coats are always much better than thick coats. If when doing this buffing, the finish gums the abrasive or the applied finish rolls into balls it isn’t dry enough.

Similar Q: I think we put the polyurethane on the floor too thick. Can we just wait longer before moving in furniture or should we redo it? If we need to redo, how do you suggest doing that? We put on 3 coats and waited a good long time in between.

A: If you applied the finish beyond what the spread rate recommends (generally 500 sq. feet per gallon) it means it will take longer to cure or fully harden. I don’t think I would start over just for this.

Related Q: I put oil poly on a stained wood floor and the poly kinda puddled up in places. Do I sand down or just put poly down again?

A: You have to make sure it is dry and hard enough to sand down first. If it powders when you rub with fine abrasive it should be fine to proceed. If this is a thick, noticeable ‘hump’ you may want to shave it down a bit with a razor knife and then sand it. How are you applying this finish? Most coatings have a spread rate, for example, 500 sq. feet per gallon. Thin coats are always better than thick. Apply with lambswool applicator or roller, depending on manufacturers directions. Cut in the edges with a brush. Don’t glob the finish on.

By the way, I should have mentioned that you must lightly and thoroughly sand the entire floor with fine abrasive or you won’t gain adhesion. The finish will peel off.

3 thoughts on “Polyurethane too thick in a few areas”

  1. i just tried the Satin Acrylic Polyurethane Wood Finish by beautitone wood shield its still got wet spots after 12 hours and thoughts???

  2. We recently created a ‘makeshift’ counter out of thin wood (1/3 thick) and painted the counter top with a flat paint, not stain (approx. 9 square foot counter). Then rolled on the fast-drying polyurethane with several coats – not thinking: 1 – the paint may not have been 100% dry and 2- should not have used a mini-roller. It was left over night and we’ve had a commercial fan on it all day, still sticky & tacky. How can we fix this?

  3. If the polyurethane is too thick – can you just wait longer before moving in furniture or do you have to re-do it?

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