Refinishing Red Oak Floors - Help with some issues after first coat

Old 08-19-08, 08:03 AM
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Refinishing Red Oak Floors - Help with some issues after first coat


We are refinishing red oak floors in three rooms. We had the floors professionally sanded, then we used filler in between cracks, sanded and cleaned up the surface (with paint thinner and lambswool after vacuuming.)

We stained with Minwax natural, which turned up quite red, but is a fairly close match to the other floors. We poly'd a small room with Minwax fast drying semi-gloss. The floor seems quite bubbled and there's not a lot of coverage. We used a paint brush to do the edges, and a lambswool applicator (dipped in poly) for the center. It has been a few days now, so I guess we can lightly sand and put another layer, but not sure how much to use.

After we did this room, I was at the store picking up more supplies and upon speaking with an expert there, decided to get the Minwax high build semi-gloss, which is supposed to go down in two coats, no sanding in btw if done within 8 hours. Used this in the kitchen. We already missed the 8 hour deadline, so will need to sand. The floor looks good in some areas, but the knotted parts of the floor are very apparent, looks like the poly seeped right in. There are also parts that look like they received no coverage at all, and then a few drips here and there. I guess those could be sanded out.

Also, in the kitchen, I did the edges with a paintbrush and we poured poly directly on the floor and spread with a lambswool applicator.

So, I suspect we are not using enough poly. If the kitchen is supposed to be done in only 2 coats, how much poly are we supposed to be putting down? What about the areas that look like they were untouched by poly? Can we just sand around those areas to try to even up the edges with the area that is poly'd and then "catch up" on our next layer? What about the drips?

Uggh. Sorry for asking so many questions, but I'm hoping someone can help us figure this out so that we don't wind up with three very messy rooms!
Old 08-19-08, 02:34 PM
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Welcome to the forums!

The label should tell how much a gallon will cover - usually around 400 sq ft but it will vary some. Some parts of the wood is more porous than others so these areas will suck up the poly and appear to not have much sheen - this will look better on the next coat. IMO it is always best to sand between coats = a smoother finish. I always like to put down a liberal wet coat. it may take longer to dry but the end result is better

You might have better luck taking a razor [or even a putty knife] and cutting off the drips and then sanding. Sanding alone will often remove all the poly from the surrounding area
Old 08-20-08, 03:36 AM
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diluting the poly with mineral spirits will elimanate most of the bubbles. I think the mixing ratio is 10 to 15% mineral spirit.
Old 09-01-08, 07:11 PM
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You don't dip the applicator into the finish.

A line of finish is poured out on the floor, and the applicator is used to "snow plow" it.
Old 09-02-08, 08:14 AM
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Different Finishing Techniques for applying OIL-BASED floor finishes are used by different finishing companies.

Some companies will pour the finish on the floor and using a "T" bar, snow plow the finish around the floor...

Other companies apply the finish with a lambs wool applicator *Rinsing the applicator first with Mineral Spirits and then squezing out the excess (dipping the applicator into a pan filled with the finish)...

Other companies will Roll their finish on, using a 3/8" nap Roller (high end rollers should be used) *rinsed out first with mineral spirits and then squezing out the excess

For the DIY'er homeowner, I suggest rolling on the finish. So with that in mind and answering your other problems/questions:

If I understand you correctly, you have (1) coat of oil based Minwax Natural Stain on the entire floor. One step that you did PRIOR to applying the Minwax Stain, was wiping the "RAW / Recently Sanded" floor down with Mineral Spirits. In doing so you did what was called "Popping the Floor", or AKA raising the grain. This is fine - IF you did it CONSISTENTLY from area to area. But, from the sounds of it, it are ok in that respect.

As far as the bubbles in the finish (First coat of Minwax Fast Dry Semi-Gloss Oil Based Urethane) - it sounds as though it flash dried (did you have all the windows open or fans going)? I know that that Oil Based finishes can have a strong odor to them (you should have been wearing a properly fit charcoal filtered mask)... but you can NOT have air flowing over the floor while you are applying the finish - this will flash dry the finish and not allow it to self level / flatten out and will sometimes create bubbles in the finish as it is drying. The other possibility is that you were applying TOO MUCH pressure to the applicator when applying the finish - Not sure as I was not there!! But your problem now, in this room that you applied the finish is to remove the bubbles. You can simply hand sand the entire room with 220 grit (lightly) on a vibrating sander. The best thing to do would be to lightly buff the floor with a floor buffer and a slightly dulled 220 grit screen, but that is going to a totally different level of expertise and best left to a professional floor sander/finisher.

After you sand the entire room that has poly on it (make sure you sand evenly and do not take allot of the poly off, you are just scuffing the surface LIGHTLY! Check you paper often as it MAY gum up). Vacuum the floor (and ALL of the other floors that have just stain on them) *use a felt wand attachment on a canister vac, NOT a household rotary brush vac!). Wipe the POLY'ed Floor down with a slighlty dampened rag (mineral spirits). Keep a small buck of clean mineral spirits handy to keep rinsing out the rag(s) in. Dispose of rags properly! Rags that have mineral spirits in them WILL spontaneously combust if not disposed of properly. I through them into a bucket of water when I was done.

The coat of stain that you applied will look splotchy (no coverage in some areas and more surface coverage in other areas) This splotchy look will disappear with each consectutive coat of poly that you apply! ie The stain sealed most of the red oak floor, the first coat of Poly continued to seal the floor and also ride on top of the areas that were completely sealed by the stain. The next coat (coat #2 of poly) will (well, should) give you complete surface coverage. The first coat (stain) you should have got about 450 sq ft to the gallon or maybe even 400. The first coat of polyurethane you should get about 450-500 sq ft and the second coat of poly you should get about 500-550, if you apply a third coat you will get about 550-600 sq ft of coverage. With each coat you apply - the more coverage you will get out of the gallon. The manufacture will tell you on the label approxiamately what the coverage rate should be. This is hard to gauge while you applying but if you use the method of NO PUDDLES, NO DRY SPOTS, NO RIDGES... you will be applying at a proper rate per gallon! Consistency in application is the KEY!

Now for the finish selection - I do NOT recommend the Minwax High Build Poly for homeowner (or professional) use. It is extremely hard to apply evenly and you do not get allot of coverage out of it. Stick with the Minwax Quick Dry Poly that you already started with.

Cut in the edges (as you did) with a 4" foam brush. Do not get too far ahead of an area. Do about 6-8 boards out from the wall at a time. You do not want the edges to dry before you get to them with the roller application! You WILL see the ridge left behind!

I suggest two (2) coats of Minwax Quick Dry on top of the stained floors with the final coat being SATIN, unless you want semi-gloss (semi-gloss will show more imperfections than satin, and Gloss will show even more!). The kitchen area should get (3) coats of Polyurethane (High Traffic areas should get (3) coats of Oil Based Poly- but you did apply stain on the first coat, so it is going to be up to you to decide. It is better to apply more coats now, then it is to have to do it a few years down the road when you are completely re-settled into the house the last thing you want to do is prep and coat a floor again!!!).

Another finish that is user friendly is Parks ProFinish (available at HDepo's, or online) here is their link...
I have used their oil based polyurethane on many floors that I have done, with no "call-backs*! Don't get me wrong, the MinWax Quick Dry Poly is equally as good, but in my professional opinion the Parks goes on easier and you are less likely to get any bubbles (from foam back).

Hope I helped you out, but I also hope that you and other DIY'ers see why PROFESSIONAL floor refinishing companies get paid what they do! It may have been worth the extra money to have the company that sanded your floor, apply the finish coats as well! The hard part (for the professional) was done already, it could not have been that much more for them to apply the Oil Based Finish coats.

Retired Hardwood Floor Installer/Refinisher

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