Well, after doing some thorough research on this forum I think I've got it figured out. I’m finishing my hardwood floors which are red oak with a oil based dura seal ebony stain and finishing with a water based urethane. Here is my process:

1. Sand 36, 60, 100 grit, edges & field with drum sander and edger..
2. Screen to 100 grit. Palm sand edges with 100 grit to get edger marks out.
3. Water pop floor, let dry overnight.
4. QUESTION….do I need to screen or sand at this point or can I just start staining? I’ve heard it’s necessary to knock down the raised grain in the wood. Keep in mind we really are going for a nice rich dark ebony color.
5. Apply stain, let set a few minutes and rub off. Let dry overnight or longer if needed. Must be completely dry.
6. Pole sand with 180 grit and clean with tack cloth. (I’m not sure about this step. I’ve read differing schools of thought on this. Some say buff some say it’s not necessary) Also, I’ve read that it is not necessary to apply another coat of stain, since the stain is already in the pores of the wood and another coat would just sit on top of the wood possibly causing problems.
7. Apply two coats of gloss water based floor finish, pole sanding with 180 grit between coats.
8. Apply final coat of semi gloss water based floor finish.

I think I’m on the right track but the only concerns I have are when to screen and when not to screen. I’ve read about maroon pads etc. but I don’t know when to use them. In the above plan, am I missing any buffing/screening steps? Am I sanding when I don't need to? From what I understand I know it’s good to screen before staining to make sure all the marks are gone since the dark stains will show imperfections, but I don’t want to close the grain too much, so screening to 100 grit and water popping the wood is the plan. Am I correct?

And am I missing any other steps such as application of sanding sealer etc? I've read about using glazes etc. I will take all steps necessary to make these floors look awesome. Thank you for your help. It’s been so informative reading all the expert opinions on floor finishing.

1) Do not edge with 36 UNLESS you are refinishing a old floor with a waxy finish. If this is new wood, 36 drum, 60 edge, 60 drum, 100 edge, 100 drum
2) OK
3) OK . Make sure to not miss any areas. Just dampen. Do not soak.
4) I wouldn't. The purpose of water pop is to open the grain to receive more stain.
5) The harder you rub, the more stain you remove. To be uniform, the stain needs to removed the same throughout the job. Don't scrub too hard or it will not be dark.
6) Absolutely not. Do not sand the stain unless you plan on re-sanding the entire floor and starting over. Do not apply a second coat of stain. It can interfere with the adhesion of the seal coat sometimes. If you didn't get it right the first time, OH WELL! 72 hours dry time for stain.
7) If you want to use a water based finish, I do not think they look they good over real dark colors unless you use a solvent sealer first. I'd use a de-waxed shellac sealer, or BONA DriFast Poly Sealer first. LIGHTY sand when dry. Then apply the waterbased finish of your choice, 2 or 3 coats, lightly abrading between coats.

You do NOT want to over screen the floor after drum sanding. It can cause dishing in the spring grain. Removing circular edger sanding scratches is to be done prior to screening. If, after all this, it looks horrid, then hire a pro. Floor finishing can't be learned in a book or on the internet. It's a very hands on skill that takes years to master.

Don't skip up grits so fast. 60-100 will cause faster wear to the finish, and be harder for the 100 to take out the 60 grits scratches. A better schedule would be 40-60-80 and then stain. Going to 100 and then staining will not take the stain as well. When staining, 80 grit is all you want to go to.

Perry, As you know, I have been sanding floors for over 25 years. The rule of thumb is to skip the next up grit in the sanding sequence. So, starting with either 36 or 40 ( there is not much of a difference really ), one would skip 50 and go to 60. Then one skips 80 and goes to 100. There isn't a 70 or 90 grit. The typical sanding sequence is as I wrote. This assumes the person sanding KNOWS how to sand and walks at a moderate pace ( 2 to 3 mph ) and only moves over about three inches per pass ( for an 8" drum machine ), with the walk back going back over the forward pas before moving over to the next pass on the machine. The problem with finishing at 80 then water popping is the floor will be too rough. Now, if the finisher is NOT going to water pop, then yes, one could use 80 as the final cut. It doesn't matter that much if the finisher/sander is going to screen to 100 anyway. IF the finisher/sander will NOT be screening, some prefer to final cut with 80, while others prefer 100. Myself, I prefer 100. It still leaves the floor pretty rough. And keep in mind, Drum sanding with 100 is much different than edging with 100. The edging will leave the floor much smoother but still with some moderate circular scratch. This is the whole reason screening was developed in the first place, to uniformly sand the entire floor. Prior to screening, sander/finishers needed to scrape and hand sand the perimeter to make the edges blend into the field. One had to use 60 grit paper to hand sand the perimeter to allow it to match the same as what the drum sander did with 100. If one final cuts to 80, doesn't screen and then water pops, the floor will be so rough that one will never get it smooth. I would not recommend doing it that way. The best results I got using very dark and white stains, was to final cut to 100, screen with 100 to even out the sanding, being careful not to over screen, then water pop prior to staining. This will open the grain enough to absorb the stain nicely but not have the floor so rough that it makes finishing a problem. Keep in mind, the the OP wants to use a water based finish, which also effects the sanding sequence and procedures used.

I'm in LA and I can't get oil in LA county, but since you said that you think it looks better with the oil base over a dark stain, I'm considering changing plans. How would that change my sanding schedule?

Great information here. Thank you.

With newer machinery available like a Trio or the use of a hard plate, how does that change your approach (when staining), or does it at all?

Gary, Whoa!! I didn't mention 70 or 90 grit!!
All I was referring to was, jumping up in grits to many, too fast, makes it harder and take longer to remove the teeth/scratch made by the coarser grit.

36-50-80 will have more peaks and valleys, then a 40-60-80 cut, same with a 60-80-100 cut compared to a 36-60-100 schedule. More peaks and valleys, make finish wear through faster.

Do you think on the same board, one side you sand to 80 and the other side you sand to 100 and then stain the board. Which side will be darker in color?

Water popping 100 grit final and final cutting with 80 before staining, seems to achieve the same dye sites.

What is wrong with 36-50-80??

I did not even know that you could go straight from sanding with the big machine and edger to staining, i was always under the impression that it would be a good idea to buff the floor before stain or finish. And in any case, after the final buffing, you could always bring it back down to 80 grit by screening again so that it could take the stain more.

However, it all comes down to preference. Every thing else is just a guildine.

If it is working for you, nothing is wrong with it.

A 36 ( or 40 ), 60, 100 IS the correct sequence and is NOT jumping up in grits too fast. It skips a grit between each and this IS the correct way to do it. Keep in mind, when using waterbased finishes, the manufacturers require you screen the floors. If you do not, it will be so rough you will nearly have to re-sand them. So, if you have to screen anyway, it does not matter whether you final with 80 or 100, because the screening will make the flooring the same smoothness. Don't get caught up in the NWFA's and 3M's hype about ridges and valleys. I could sand a floor with 50 and go to 100 and produce a flawless sanding job. I've done it many times. One just needs to KNOW how to operate the equipment ( sander ) well and be very experienced. Your suggested sequence of 40, 60, 80 does NOT skip a grit between 60 and 80, as suggested by NOFMA, 3M and the NWFA. Now you could do the 36, 50, 80 routine, and that would correctly skip a grit between each pass. I do NOT like floors final sanded with 80. It is too rough, even if staining and coating with a solvent finish. I did refinish just last year where the customer wanted a darker, uniform color. I final sanded to 100 with the big machine, then scraped and hand sanded the edges with 60 grit floor paper. I did not screen or hardplate prior to staining. I did it very old school. The stain took nicely, penetrated well, did not bleed back, and achieved the desired appearance. After drying, I applied a coat of 550 voc OMU at 500 ft. per gal. After that dried, the floor was quite rough. I needed to thoroughly screen and then pad it to make it smooth enough for another coat. I was concerned I would cut through the finish and remove some color. I think I did in a few small spots. The lesson behind this is; had I used 80 to final the floor with, it would have been even rougher and more difficult to achieve a smooth finish. No, the correct procedure to make a floor dark using waterbased finishes IS the one I outlined above. But as you know, there are many ways to skin a cat. And what works for one, may not work for someone else. The other factors involved are the equipment ( sanders ) and the quality of the sandpaper. Regardless of what manufacturers say, I find different companies grits are not the same. Virginia Abrasives 100 is different than 3M's 100, which is different than Norton's 100. Shouldn't be, but they are. So, with my tools and my abrasive brand choice; 40, 60, 100 works best in almost every situation. Then I do what is needed from there to achieve the appearance I'm shooting for and the products I'm using.

"The lesson behind this is; had I used 80 to final the floor with, it would have been even rougher and more difficult to achieve a smooth finish."

What it's really telling you is since you didn't buff the floor with a 1oo grit screen prior to staining,the floor would be excessively rough. Because that roughness is torn wood fiber from the drum sander..Buffing would have gotten rid of that

Gary you are awesome.

I think you are one of the best at using the written word to articulate the complexities of our business.

Floorguy with all you experience you should know that "there are many ways to skin a cat", as Gary put it.

DUH, ya think so? I suggest you go back and carefully re-read the entire post. With the dark floor I was doing, I specifically chose NOT to screen the floor, which was the way it was done for many years prior to screens being introduced. Floorguy's assertion was that one should stop at 80, then stain ( with no screening ). My assertion is that even after a final cut of 100, it still leaves the floor a little rough. I am completely aware that I could have screened the floor ( and I often do if going natural or light to medium colored stain ). However, since I needed to go DARK, there are two possible ways to achieve a nice dark uniform stain job. One way promoted by Bill Price and many other old schoolers, is to NOT screen and final cut to 100. This leaves the surface still rough enough to absorb well, the heavily pigmented dark stain. This is the procedure I chose on this job. The other option is to sand to either 80 or 100 ( it does NOT matter which one if you're going to screen after ). Then screen the floor properly and vacuum. After that, one needs to water-pop to "open up the floor" again to be able to stain the floor a deep color. Both procedures can and do leave the floor a little rough after the 1st coat. One could burnish the stain a little with steel wool or a maroon pad prior to the 1st coat. But then you risk removing a little color as well. We used to do this way back when prior to waterbased finishes and screening. Either way will produce a nice, deep colored floor. I would not recommend using a waterbased finish or sealer over this dark, slightly rough stained floor. I used full strength BONA Woodline OMU because I wanted a "fat" 1st coat that would dry well and sand easily. BONA Woodline fits this need. After the first coat dried, buffing to achieve a smooth finish consisted of lightly screening and using a maroon pad.

So, I am completely aware of the whys and hows of all these various approaches to sanding and staining a floor. There is usually not a "one size fits all" approach. Every floor requires the finisher to properly assess the job and use the proper procedure that will satisfy the customer's desires.

Thanks! I swear, one day I will write that book I've been talking about. Just that with the internet, a book on floors seems redundant. Maybe I write a international spy story instead

Gary,
I guess I didn't see where you were coming from....I've done the same type of thing by hand with 60 grit to get the floor to take the stain darker (tends to not tear the wood fiber as much)after applying the first coat of poly I go over the floor by hand with 220 grit....Comes out pretty good....

By the way Gary I already know how good your work is,I know a craftsman when I see one