Is it right that first poly clear coat is being put on only 2 hrs after sealant?

Q: We think our floor guy walked out on us today. We had dark oak engineered floors that were badly scratched, but our floor guy said he could sand them down and make them look better. We decided to go with clear coats/no stain.

He said he would put a sealant on and then 3 coats of polyurethane. I was led to believe for some reason that he would buff or sand between coats.

2 Hours after he put the Bona HD sealant on, he had already started putting on the first poly clear coat. 2 Questions – Was he supposed to buff or sand between? And second, is two hours enough time before applying the first clear coat?

I don’t think he is coming back! Will we be okay if it takes us some time to get the last 2 coats on?

A: While Bona Kemi does have one oil modified sealer and polyurethane to offer, they mostly manufacture water borne coatings and sealers. It does sound like your floor guy was applying the latter. These types of finishes set up and dry quite rapidly in time frames of anywhere from 1-3 hours. When they are dry they can be recoated. The best way for a floor mechanic to know if his coating is dry is by using a moisture meter taking an average reading before finish application and then checking after the finish can be walked on to make sure readings are back down to where they were initially.

Now, that little bit of trivia aside to answer your questions: yes they can apply the coatings that soon with a water borne coating. No sanding between coats is necessary provided the next coat is applied within a specified number of hours, thus achieving a chemical bond. The main reason sanding or buffing would be done would be because of grain raise with the initial coat of finish or sealer. This buffing would only need to be done if there was grain raise or if the allowed time for chemical bond had been exceeded. And yes, on an unstained floor, they do recommend a sealer application followed by 2 or 3 coats of a product such as Traffic. It sounds to me he still owes you two coats. And now he will likely need to buff once for the two coats.

Personally I would be afraid to apply more than two coats of water borne in one day. Don’t forget, there is a small amount of water in the coating. Water is an enemy of wood. Applying too man coats in one day could cause excessive stress and cupping of the floor boards. He may have applied two and intends to come back tomorrow. One on one communication is a good thing.

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