sanding sealer under polyurethane (oil based) on floor?

[dicktill]

Hi,

I may have been led down a bad path by an overzealous guy at Home Depot. He told me I had to use sanding sealer on my new oak floor before I finished it with oil based polyurethane. He sold me some water based sanding sealer. Just after I got it down (with too many bubbles that I have to sand out now  [crying]), I read another chapter in Bob Flexner's great "Understanding Wood Finishing" (I can only get through one chapter every evening or two [eek]). He specifically says not to use sanding sealer under polyurethane! [tongue] Should I sand it all off, knowing that I probably won't get it out of the pores?

Thanks, Dick

 

[tjbnwi]

Screen the floor (floor buffer with fine sanding screen). Return the oil poly (it may be fine, why chance it), use water poly. HD here has Parks. Be better if you got some water Bona.

I use sealers under poly all the time.

Tom

 

[Scott B.]

Flexner's book is good. Unfortunately, it was published in 2010, which in the constant state of change in the finish world, it was outdated just about as soon as it hit the shelves. Technologies are changing daily. I use Zinsser Bullseye shellac base with Zar Ultramax satin oil modified all the time.

 

[JPF Woodworking]

If you are going with a water based poly I would strongly recommend General's Enduro Poly (not sure of the spelling). I was doing an oak stair case recently and couldn't use oil poly because of the fumes. Tried this product and was very, very impressed. Four coats went down very quickly- day and a half- dries in a very short time depending on humidity. I couldn't be happier with the final finish. No odor at all, very easy clean-up- almost everything you could ask for in a finish. The only downside is the price- $91 per gallon (Rockler).

 

[Brice Burrell]

Screen the floor (floor buffer with fine sanding screen). Return the oil poly (it may be fine, why chance it), use water poly. HD here has Parks. Be better if you got some water Bona.

I use sealers under poly all the time.

Tom

We have Bona at HD in my area, you might want to check in your area.

 

[RDMuller]

I have been experimenting on a few "semi-hidden" areas of a cherry kitchen floor to test out General Finishes Enduro polyurethane which is water based.  Here is where we are at:

3 coats of Enduro gloss on raw sanded cherry wood (Festool 150 with 180 Granat paper).  Went down easily in a 1/2 day.    Just for "giggles", I sanded the last coat with 1200 granat in a Festool 150/3, threw down some auto polishing compound (3 M's  Finesse It) and polished that with a Rotex 150 in gear driven rotary mode with a sheepskin and then the orange foam pad. 

Result:  Very impressed with ease of putting Enduro material on.  I used a CAT Jaguar HVLP conversion spray gun.  Wear a respirator.  Even though these water-based products don't stink and they dry fast, that does not mean they are good for your LUNGS.    Think about that --- just because it doesn't smell doesn't mean its good for you!  Lungs can't be replaced.

Polishing out with the rubbing compound was very easy.  The test area has a wonderful shine and the labor to do this would be nothing overwhelming to think about rebuffing periodically.  This was EASY to do.  Is it a good idea???    I don't know.  I called GF tech support (they are great by the way) --- first thought they had was if the floor would be too slippery.  I wondered that at first also.  After mopping this a few times with water, I don't think that will be an issue.    Will I do the whole floor this way?  I don't have any idea yet.

Next issue on GF Enduro -- this product is supposed to amber up the wood a little.  It did, but not as much as I want.  (Enduro is much better on this cherry than the acrylics from other manufacturers I have tested).  GF tech support suggested I try up to 5% of their water based dyes as a toner in the first coat of finish.  I had not thought of this even though I have shot a lot of solvent based lacquers with added dye in them to get the color correct.  I have used a lot of ML Campbell product for this lacquer work on furniture and cabinets.  I have bought 3 of the GF dyes and will experiment (Rockler does have the dyes in the store.  They are premixed).

Alternative to amber it up from GF tech support ---  use GF "Seal-A-Cell"  not sure on spelling.  Use this only as a first coat.  This is an oil-urethane mixture.  Followup with Enduro.

I did not get a response to ambering up with amber colored Shellac.  I will also give that a try.  I have used shellac as a barrier coat in other finishing systems and it hasn't let me down yet.

By the time I get done with my experimenting, I will be out of "semi-hidden" areas to test on.  I will make my best pick based on color and appearance.  Then I'll have to sand them all off.  I am not sure if I want this finish to be "easy sand off" or "hard sand off".  Hard would most likely be an indication of long-term durability.

Incidentally, the Rotex 150 with grant 80 to 180 is great for sanding a small area of factory finish off for testing, but would be way to small a unit for the whole floor.  I will rent the random orbit floor model that Menards has the I believe has Varathane stickers all over it. 

Any inputs from other FOG-ers on what I am trying are welcome.

 

[tjbnwi]

Screen the floor (floor buffer with fine sanding screen). Return the oil poly (it may be fine, why chance it), use water poly. HD here has Parks. Be better if you got some water Bona.

I use sealers under poly all the time.

Tom

We have Bona at HD in my area, you might want to check in your area.

An email about this was in my inbox this morning.

Tom

 

[Brice Burrell]

I have been experimenting on a few "semi-hidden" areas of a cherry kitchen floor to test out General Finishes Enduro polyurethane which is water based.  Here is where we are at:.........


Any inputs from other FOG-ers on what I am trying are welcome.

I have a thought, why bother?  There are so many great products made specifically for floors that are readily available.  Also, polishing a floor, crazy.  You want a gloss finish, put down a gloss finish and be done with it.  HVLP spraying a floor, not what I would do.  Pour the finish on the floor, brush, roll or mop it out, done.  These things are the convention for a reason.   

 

[mouppe]

Why do you need to use a sealer? Because the oak is open-grained? Maybe you want that look, in which case go straight to the poly, whichever delivery method you choose to use.

 

[TinyTiger]

I use sanding sealers under oil based poly frequently without any problems at all.  My favorite is also the Bullseye Shellac thinned 50% with denatured alcohol so it flows better.

 

[tjbnwi]

Using oil poly sanding sealers is not necessary. Using water poly the tannins can cause the finish to yellow. Sanding sealer prevents the reaction.

Tom

 

[dicktill]

Thanks for all the suggestions.

I did a test by taking three pieces of scrap flooring. I applied sanding sealer to two of them. When thoroughly dry, I just lightly sanded one to roughen it slightly. The other I sanded heavily to remove as much of the sanding sealer as I could. Then I applied the polyurethane ("oil modified", Fabulon) to all three. The one with no sanding sealer and the one that I had sanded it all off of looked much like my existing floors (also done with Fabulon, almost two decades ago by pros [just two coats], and still looking great), while the one with the sanding sealer intact looked much paler/whiter, a look I personally (and my wife) didn't care for nearly as much (YMMV). And since the new flooring in this small office meets/butts-against the existing hallway flooring, this was the look we wanted. So I sanded off the sanding sealer on the new floor, and applied the first coat of the Fabulon today. It looks great, and should look even better with a second/top coat. And I did so much better than I did with the water based sanding sealer: i.e., no bubbles, even though both were applied with the same lambswool applicator.

Regards, Dick