Restained in stages, resulting in various shades?

Q: Several years ago I refinished our oak floors and restained in stages, resulting in various shades of walnut. I used both water borne polyurethane and oil-based clear coat in other areas. Would a commercial upright random orbital sander used with the intent of removing the surface finish suffice as a restaining base?

I did use filler on all floors.

I would appreciate and advice or comments. The intent, of course, is to have a continuously consistent surface. Also, are there any particular final finishes that you recommend?

A: To re-stain you would need to remove all the existing finish, so I think you should just take the entire floor back to bare wood. Make sure all the floor areas are prepared in the same way, using the same techniques and abrasive grits in all areas. It should be noted that most (but not all) water borne urethanes tend not to amber like solvent (oil based) finishes do. So, to use different finish types in different areas will cause a different colour over time.

I love Poloplaz Primero. It rolls beautifully and is quite tough when cured. It is solvent based but doesn’t amber as much as some similar products. If you want a finish that stays clear, doesn’t smell and dries fast then Poloplaz 202 is a really good option. While it is a 2 component finish, the hardener is actually pre-added to the gallon jug. This means little to no finish waste. Other high end water borne coatings have a separate cross linker (often iso-cyanate) and has a very limited pot life of hours to a day or so.