Refinishing our floors, the 1st coat of semi gloss polyurethane was very shiney which we liked, but 2nd coat looks like satin that we don’t like, we were told not to stir to prevent bubbles, could the 1st coat have been high gloss and last satin since not stired? Can we put semi gloss on top of this to get some shine?? would like it to look a little shiney and not so flat, appreciate any help
Second coat probably took-on water moisture.Let it mature a month or two before making a final decision. Keep your ac on at 76 and allow time to pass.The humidity must stay around 48-55% and rarely higher. It might dry and harden to a nice look and evenness.
The stuff that makes the varnish semi-gloss rather than gloss can settle to the bottom of the can and stay there unless it’s stirred up and mixed in. It’s possible that when you put on the second coat, you used stuff from further down in the can which had more of the dulling agent in it. I’ve taken cans of polyurethane back to the store because the stuff had settled so firmly in the bottom of the can that it couldn’t be stirred up and mixed with the rest of the varnish without staying in hard lumps. Stirring is okay. It’s shaking you must avoid, like they do in those machines at the paint store. You can stir more vigorously, if you must, the day before you use the varnish, then stir it lightly on the day to make sure the dulling agent is evenly distributed. This gives any bubbles a chance to rise to the top and dissipate overnight. Read the can, it should say to stir but not shake, and always stir slowly and gently, and maybe even to stir gently during application, which makes sure the dulling agent stays suspended.
But, if you like very shiny, why are you buying semi-gloss? You should be fine putting gloss over semi, especially since you must sand between coats. Use a very fine paper for the sanding.
Semi Gloss Polyurethane