Water based poly on water based simply white stain turned yellow, where do I go from here?

[Mkuckie]

We are doing our own refinishing of oak hardwood floors. We did sanding, we applied water based simply white minwax stain and it was looking good.
After drying over a day we applied water based minwax poly first coat. Came back after 4-6 hours as we worried the humidity of the day would make it take longer to dry. Walked into lots of yellow spots. Now, we had a feeling in living room space it may happen as when we were finishing up poly, the poly was turning color, so we figured the applicator got dirty.
But even in other rooms we had yellow spots. I understand it can be from spots that are too heavy.
What is honestly best approach to fix this and to apply poly to floors and not have this continue to happen. Attached photos of before poly and after. I love the color of stain as it was before poly. We also did satin finish of poly using brush on edges and water based paint/stain applicator for large areas.

 

[Mark Brown]

Perhaps contaminates left over from not sanding them out?
In that photo of the unfinished floor in what looks like the same location as photo 753 it would appear that it was not sanded out super well?

 

[C.J.]

How thick did you put the water based poly on. Putting on too much will have a yellowing effect. Regardless of what happened the solution is to sand it off and start over. You don’t necessarily have to sand all the way back down to bare wood but just enough to get past the yellow poly so maybe screening is a better word than sanding. Multiple thin coats is the trick with water based poly as opposed to oil based poly where you actually want to leave a fair amount on the floor.

You can get sanding screens for your palm sander. I would use that to get at the yellowing spots then use a floor buffer to screen the entire floor if necessary to blend it all back in. You may get lucky and just the palm sander will do the trick. Come to think of it a floor buffer may be a bit aggressive if you’re not familiar with using them. You can hand screen the floor to abrade the surface but not get too deep into the stain. Let the poly thoroughly dry otherwise it will gum up your screens. Tack the floor between standing and coatings. This will help to reduce/ eliminate junk n gunk from getting in your finish.

Take your time and best of luck. Your floor will be beautiful when it’s done

 

[highup]

I was thinking at one time one of the local paint stores had a square, vibrating sander I think maybe 12x18 inches? It would be a lot easier to control than a standard buffer but I don't know if these things are commonplace. I would assume they make screens for them.

 

[C.J.]

I was thinking at one time one of the local paint stores had a square, vibrating sander I think maybe 12x18 inches? It would be a lot easier to control than a standard buffer but I don't know if these things are commonplace. I would assume they make screens for them.

Darn fine idea, High. HD usually rents those and they’re not nearly as aggressive as a 17” orbital buffer which would prolly make them ideal for this situation.

 

[MikeAntonetti]

In my line of work, you need fine tuning equipment and beast heavy duty stuff, everything in between and beyond whatever is practical to purchase. Square Scrub comes to mind for the orbitals, I use to get emails all the time for the cleaning industry.

 

[highup]

In my line of work, you need fine tuning equipment and beast heavy duty stuff, everything in between and beyond whatever is practical to purchase. Square Scrub comes to mind for the orbitals, I use to get emails all the time for the cleaning industry.

Are those square scrubs orbitals?
I've never known what kind of motion they have.

 

[MikeAntonetti]

Orbital, oscillating, vibrating. I haven’t distinguished the differences. Their Website seems interesting.