Amateur wrote:
A floor refinishing company has told me they can stain our pine floors by
mixing one or two small cans of minwax stain with the Ace polyurethane
they use and apply both things together at once. I was under the
impression that you'd have to stain the floor first and then later apply
the polyurethane to seal it... Is the method they are proposing to do
really viable? Also, how many coats of polyurethane would be recommended
for pine floors?

RL

There may be method to their madness, as pine is soft and can absorb
stain in inconsistent manner. Is this a new floor, never finished? Old
floor with old finish on it? Old floor, stripped?

The prettiest finish I have ever seen on pine was woodwork with only
sanding sealer used on it. When I finished some new pine furniture, I
made my own stain; artist oil colors in very dilute ms, oil and varnish
mixture. Let it dry and put clear varnish over it. Chose color that
would help counteract natural yellowing of pine as it ages. It worked.

If on bare wood, some of the finish would undoubtedly sink. I would get
more particulars from your floor company and ask to see their work.