I stained this pine board 24 hours ago with some Sherwin Williams stain and it looked great. I wiped it on, and then wiped it clean. Now, I have wiped on some minwax wipe on poly and noticed that the the rag kept getting darker and darker. After about an hour, as the poly drys, it looks like I have wiped some of the stain off (it actually looks really bad). The thin spots almost look like there is sap in it. It that possible in a high grade of pine

Can I sand the spots where the stain looks thin, reapply the stain, then put another coat of poly on without the entire board's stain looking uneven?

Do I have to sand the entire 10' board clean?

Should I just reapply the stain on the thin spots?

Any advice would be greatly appreciated.

 

I would throw the board away and start over. Or sand and finish the opposite side, if you can.

Your polyurethane will act as a sealer, preventing the wood from accepting stain. Your wipe on poly is basically like rubbing paint thinner on the board, so the more you rub it, it will basically scrub some of the pigment off of the wood. Not sure why you would be having this problem, unless you didn't really wipe the stain off as well as you think you did, and the stain wasn't really dry. For instance, were you rubbing it dry with a stain saturated rag, or a clean dry rag? And I'm wondering what stain you used? Was it SW wood classics interior oil stain?

If you are going to use the same product to stain and finish the 2nd time, I might recommend that once your initial application of stain is dry, you get a spray can of polyurethane and spray on a light coat over the stain to "seal" it. Once that spray on finish is dry, give it a light sanding with 220 grit, and then you should be good to go with your wipe on poly. Personally I have never saw the need to use wipe on poly, I don't have a problem using a brush.

 

I agree with XSleeper on all points