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Most everything you're doing sounds fine with one exception ... using an orbital sander.
When you sand polyurethane in preparation for another coat, your 220-grit paper should always go in the direction of the wood grain.
The paper in an orbital sander rotates in irregular semi-circles. So even though you may move the tool up and down the board in the direction of the grain, the circular motion from your power tool is actually cross-cutting the grain and making the surface coarse.
Try hand sanding with 220-grit sandpaper wrapped around a sanding block ... and move only in the direction of the grain.
Your results should improve dramatically!
NOTE: In the recent past, another Community Member asked "How to Produce a Glass-like Polyurethane Finish?"
Click the link and you'll see step-by-step instructions, tips about brush selection, and even what type brush stroke to use.
When you complete your project, come back to post photos and discuss your tips for success.
I got the water based minwax product that I've applied (3 coats) on the Brazilian pine wood shelf. During application I was fighting with wood grain but so far unsuccessfully. So after third coats I still have some areas that are not pleasant to touch. Is there way to fight with raised wood grain problem ? So far I'm trying my best with random orbit sander (220 grit) and apply next coat. Any other suggestions are welcome.
Some stores carry the Minwax waterbased polyurethane in jug form - but not all stores do. I was able to pull a Q and A section directly from the Minwax site offering you the comparison you were looking for. It is very similar to the PRO product PatNPaint mentioned in his post.
Q. How durable is Minwax® Water Based Polyurethane for Floors?
Water Based Polyurethane for Floors provides durability that is comparable to oil-based polyurethanes. It is significantly more durable than most water-based finishes available to consumers.
Q. What is the difference between Minwax® Water Based Polyurethane for Floors andMinwax® Super Fast-Drying Polyurethane for Floors?
While both products provide superior durability for protecting hardwood floors, Water Based Polyurethane for Floors has little odor, dries in 2-3 hours and application tools clean up with warm water.
Q. Can I Sand and Recoat a floor that was previously finished with an oil-based polyurethane?
Yes, as long as the floor is prepared following the label directions.
Q. How many coats do I need to apply to protect my floor?
Three coats of Water Based Polyurethane for Floors are recommended. Additional coats may be applied for added durability.
Q. Is sanding required between coats?
Water Based Polyurethane for Floors should be sanded between the last two coats only. This process is common with water-based floor finishes, especially those available to professional contractors. Water-based finishes, such as Minwax® Water Based Polyurethane for Floors, are applied in very thin coats. And, each time you sand, you remove some of the finish. So, sanding is not recommended except before the final coat.
Q. Can Minwax® Water Based Polyurethane for Floors be used over oil-based Minwax stains?
Yes. Water Based Polyurethane for Floors has been formulated to work within the Minwax®system. For best results, we recommend staining with Minwax® Wood Finish™ stain. Make sure that the stain has cured completely before applying Water Based Polyurethane for Floors.
Q. Can Minwax® Water Based Polyurethane for Floors be applied over Minwax® Water Based Stains?
Technically yes, but it is not recommended because water-based stains are not well suited for use on floors. Water-based stains dry very quickly, making them difficult to apply evenly, without lap marks, over large surfaces. For very large surface areas, such as floors, we recommend using an oil-based product such as Minwax® Wood Finish™ stain.
Hope this helps.
NOTE: MinWax has several water-based polyurethanes ... Polycrylic (in the blue can) is not for flooring.
So, I want to make certain which product you are suggesting.
This water-based polyurethane is currently sold at The Paint Pit.
Click the link to go to MinWax Professional Water-based Polyurethane.
After you jump to the linked page, click the orange tab labeled "Specification" and you'll see the details.
On the manufacturer's site, application instructions for Pro Finisher (pictured above) says, "Allow to dry 2-hours and recoat before 24-hours. After 24-hours, lightly sand with 220-grit sandpaper before applying the next coat."
In addition, I spoke to MinWax on your behalf and their representative said, "After cured, there is no difference in durability between their water-based polyurethanes designed for application to floors."
NOTE: I was not able to identify the other product (in the can) you mention ... so, should you choose it, be cautious to review the label and follow application instructions carefully.