Minwax Satin Clear Oil-Based Fast-Drying Polyurethane 2.5 gal

I don't write reviews but in this case I thought this may be beneficial for others. My project was 200 board feet of bookcase, six bookcases each with four shelves and side supports all made from sassafras planed and sanded down to 220 grit. The penetrating stain worked as stated on instructions on can and looked beautiful. I used provincial wiped off after 10 - 15 minutes with paper towels and applied gunstock as second color because customer liked the idea of a red/orange tint to the rich brown color of provincial. My challenge was the polyurethane application. I live in. Eastern PA and stained and poly starting beginning of December, outside temperature was variable from 30-50F days, 25-30F at night. Work area was detached three car garage so controlling temperature was the issue. The first application was perfect just as stated on can and met my expectation. The second application was not as expected. In order to speed up project I pinned front and back of each shelf so I can apply polyurethane to the front and back and sides of each shelf and set with bottom side down to dry on garage floor. The next day the back of all shelves looked great just as expected, but the top of all shelves which was faced up in the garage had uneven drying (satin and flat areas intermingle showing brush marks). Perplexed, the day of second application was misty rainy day and I thought it may be due to moisture made its way into garage. Upon review of how to cure moisture problems with polyurethane (difficult and risky) I decided it may have been due to cold temperatures the night after second application. I applied third application using new gallon can of polyurethane (in case first can had moisture contamination) and new 4" chinese bristle brush made for this type application. I also added kerosene heater and fan to boost heat and ventilation to enhance drying more along the lines of what stated as best case on can 77F, I was able to achieve 65F and 55 humidity. I am 9 hous into dry time and things are looking betterd -smooth surface even drying . The look is still flat but starting to turn satin. I hope this helps others. My challenge seems to be controlling all the variables to achieve the desired outcome.

I used this twice - once without stirring every 15 minutes and once stirring that often.  It came out flat (satin) when I stirred as directed.