Question:
The floor guys used shiny polyurethane on our newly-refinished floors, even though we had asked for satin. They put down only one coat and don’t plan to come back — and I don’t want them back. My question: Can we sand ourselves and put down a second, satin coat, and get rid of the brightness? Thank you.
Answer:
Dear Pat
I got both of your emails, and I am sorry to hear that you won’t allow the floor guys back. It’s just that they could have done the screen and recoat a whole lot easier than you can. But don’t worry, I will explain exactly how it is done. There is however a cheaper and simpler option, but it has its drawbacks. And that is to paste wax the floor. Wait for the poly to cure for at least 30 days. And here is a little exert from the second part of the cleaning article about this method of “dressing up a floor finish”.
There are two available; Lite n Natural by Bruce at www.bruce.com, or try Dura Seal’s Liquid Floor Wax at 800-526-0495. These waxes have about the same consistency of semi melted butter. That makes them easy to apply, and be sure to do a thin coat. It will haze over when it’s dry (about 30 minutes), and then you can buff it with an electric buffing machine. Try to find one that has natural bristle pads on it, this will easily buff the floor to a nice satin sheen. You can also use the paste waxes from those little tins. The best method for these is to wrap a golf ball sized lump of wax into a piece of cheese cloth. Squeeze it gently and apply a thin coat to the floor and buff it when it hazes.
Now the major problem with this method is that the floor will never accept another coat of poly in the future. You could never be sure of removing all the wax, and we know that nothing sticks to wax. Paste waxes have a nice satin sheen to them though, but they are mostly used on older more worn floors.
So instead I’m going to send you the section of the article about just how poly is applied without pits or bubbles. You just need to see the middle section of the article, as the whole article assumes one is starting from scratch. Oh, and in your case the contractor’s one coat of poly is just to little finish on the floor in any case. They probably used a cheap sealer as the first coat, then applied only the one poly layer. So adding another coat is really worthwhile. The finish the contractor used should be dry enough for recoating in just 2-3 days after they have finished. But you can do it any time, up to say a year from now. Beyond a year the one coat job may start to wear out, so get it done. A buffing machine is also called a floor maintenance machine, and almost all rental places have one, and sell the screens also. Use a 100-120 grit screen.
I also don’t know if the floor was stained before coating, so I’m just sending you the whole section. If you have a clear finished floor (some call it a natural finish) you need not be so careful. But if they used a lacquer sealer as the first coat, you should just take care not to screen though the thin coat of poly, and past the sealer. If you do, the poly you apply will color that spot darker than the rest of the floor. Don’t worry this is definitely a DIY job, just follow my instruction to the tee, it’s not rocket science.
And now, once you are quite certain that the first coat of finish is quite dry, you can proceed in the screening. Use your buffing machine with the handle low to the floor, you don�t want to gouge too much finish off the wood, after all this is only a thin coat. If you have stained the floor, and are buffing the first coat, you must take even more care. Run the buffer in a corner first, and I suggest you dull the screen by sanding the screen itself. See if you are removing too much finish and are thereby removing the stain to the bare wood. This is a delicate operation. On the one hand you want to scuff the finish. Poly just will not stick to itself otherwise. But you don�t want to sand though the finish into the delicate stain. You may have to hand screen the floor instead. That�s why I always apply a smooth but heavy (500 sq. ft. per gal.) coating over my dried stains. But I still take care, and that�s why I charge almost double to sand and stain a floor. It�s a risky job.
Run the buffer in both directions never stopping in any spot, just a nice easy back and forth motion. Go with the run of the wood, then repeat again against the run of the floor boards. This assures you that all low spots on the floor will have the finish well scratched. Next, get on your hand and knees and scuff sand the floor in all the areas that the buffer couldn�t reach. All along the edges. This gives you a chance to see if all the pits, lumps and blobs are sanded down smooth and flat with the surrounding finish. You may have to gently scrape out some blobs, and really sand those pits until they are not visible. The more fussy you are now the better the next coats will come out. This is precisely why you need a really dry finish, else all this scuff sanding will just make a gummy mess. Be patient.
One you have a 100% scuff sanded finish, and it feels as smooth as a baby�s behind, you can start cleaning up. Vacuum twice again, with your industrial vacuum. Get into all the corners of course. Now you can tack rag the floor. I use white lint free rags (yes you can get lint free cotton rags at most big box stores, expensive but worth it). Choose the most lint free in rag in the box, and wet it well with paint thinner. In this case paint thinner is just right, it dries at just the right rate for cleaning the floor. Fold the rag in a long narrow bundle and using both hands on your knees wash the floor in a back and forth sweeping motion as you crawl backwards. I wear my Pro Knee knee pads so even after 23 years on the floor, I can still do this with comfort. And hey, I�m not here to tell you the easiest way to prep a floor, just the best way.
I started tacking between coats of poly 21 years ago, and doing this on your knees is the best way to clear that fine powdery dust that the vacuum cannot suck up. Let the solvent dry completely. Don�t coat over any solvent, this will interfere with the poly and cause bubbles. You want the second coat to be almost perfect. When the solvent is dry and before you coat the floor check for dust and debris one more time, with your hand. If it is still dirty, do one more tack ragging.
Now we come to the fun part, brushing on the finish. Yes I said BRUSHING. I quit using lamb�s wool applicators about 10 years ago, when I tried to clean one of these dirt collectors. After only 6 months of use (and cleaning between uses) I soaked it in solvent, and try as I might could not get all the dried caked finish globs and bits out of the interior of the lamb�s wool pad. Instead I purchased an 8� Embee natural bristle brush, and have always been able to clean this free of all contaminants. I now also have a 12� short bristle brush that I use on small jobs by hand. The longer nap Embee brush can be taped onto a pole and is almost as efficient as the old lamb�s wool applicator, without making the bubbles or leaving behind the junk. If you wish not to invest in $100 brushes at this time, I would recommend the 4� Purdy brand bushes, with the unvarnished wood handle. You may have to spend 30 dollars on a brush like this but you will never wear it out.
Now here�s your floor brushing lesson. Filter the finish into these large disposable aluminum roasting pans. I buy my floor finish in 5 gallon containers, so I just have to put a few layers of cheese cloth over the spout held on with a rubber band. You do need to filter these reactive type varnishes because they are always in some state of curing some dried film in the can. The older the can the more junk is in it. I pour the finish slowly into the shallow roasting pan, so I don�t create bubbles in the finish. The shallow pan will release the bubbles faster in any case than a deep bucket. If you are using a satin finish (which I always do) you will have stirred the finish gently before you pour, to mix up those flatteners.
Choose a game plan. You will want to do only a swath of finish that you can conformably reach across, so if your are applying the finish by hand with a brush don�t do more that a 3 foot by two foot area at a time. And if you are using that brush on a pole you can increase this to a 6 by 3 foot space. Of course each area will be one block in a series with the run with the floorboards. If this is parquet floor you will want your long swath of finish to be pointed at any windows, or parallel to a long wall. In either case keep the final brush strokes going always in the same direction for all coats. So, first wet the area by brushing in any direction, then comb the finish once and only once in the chosen direction. You will have only brushed the finish twice, so have not created too many bubbles in the finish. You will have overlapped the previous area just a few inches, so as not to disturb this last patch too much either.
Do this slowly and deliberately, and if you are on your hand and knees (the best way to coat a floor if you have the really great Pro Knee pads), you will be able to look at the light from the window reflected off the floor, to really see what you have missed. Overhead lights, and coating a floor at night are not good at all. You need that angled light that only windows and strong sunlight can provide. I never start coating a floor past 2 PM. I just wait for the next day. Again I�m trying to tell you the best way to coat of floor, and if you are impatient, and rush through this second coat, you will have a lot more work to do before the third and final coat is applied. And if you are production floor mechanic I�m sure your eyes glazed over when you heard I brush on my finishes. Close the screen page now if you are too impatient to read this whole treatise. Your finishes will be forever bubbled and a pox on you.
Always keep the floor temperature at 70 F, and I mean not just the air temp. The wood itself needs to be 70 F. If you have an unheated crawl space under the floor the wood may not actually be that warm. I have a few more hints. Wear a hat when coating (we hate to see hairs caught in the finish), and be sure to wear clean clothes the day of the second and third coat. Ventilate all coats with a large fan about 4-5 hours after the finish is applied (or when the surface is hard enough not to have dust stick to it).
And Pat, the finish I use is the Fabulon Brand heavy duty satin polyurethane (800-364-1359). It’s just the best satin poly out there. You should be able to find this brand at a supply shop that caters to the floor trades themselves, not one of the those floor boutiques.