Blinded by the light.

February 9, 2008 6:05 AM

D'oh! I refinished a floor with gloss polyurethane when I should have used satin. How do I fix this problem?

The floor: 11" wideboard pine. My project: sand to bare wood and apply three coats of poly (without a stain) to match the other floors in my house.

On the third coat, I ended up with that all-to-familiar gloss poly "shine." I'd been using gloss poly instead of statin--major d'oh!

Rectification advice? I don't have time to sand back to bare wood, but have no aversion to laying down three additional coats of satin poly--if this will cut down on the shine. Thoughts?

posted by Gordion Knott to home & garden (9 comments total)

you don't need to sand down to wood or apply three extra coats. just lightly sand the floor at the highest grit you used and then apply one final 'satin' coat of the same stuff you used before.

the sanding is to make sure you get proper adhesion to the gloss finish.
posted by geos at 6:25 AM on February 9, 2008 [1 favorite]

just to be clear, the sanding is just to scuff the glossy surface, you don't need a floor sander...
posted by geos at 6:28 AM on February 9, 2008

Second geos, a single coat of satin will produce a satin finish. Scuff with a 120 grit for good adhesion. I used a square 1/4 sheet palm sander for this hooked up to my shop vacuum cleaner. It is a heck of a lot easier on the arm and and poly dust doesn't get all over the place. Get the high efficiency bag for the shop vac to capture the fine dust and then dispose of it outside preferable in a metal can if the current finish is less than a month old as there is a fire risk from the polyermizing polyurethane.
posted by Mitheral at 7:26 AM on February 9, 2008

I would do the above, but use a higher grit then 120, I would be concerned about going too deep with that. I would suggest using 180 or 220, and make sure you go easy on the poly.
posted by BobbyDigital at 7:59 AM on February 9, 2008

You did it just right, actually. If you want a satin finish, you're not supposed to use satin for all three coats, otherwise it will look muddy. You're supposed to do two coats of gloss, then a final coat of satin. Your one extra coat of gloss is just going to give you that much more depth. Good job!
posted by Enroute at 8:30 AM on February 9, 2008

mitheral- how does one hook up a palm sander to a shop vac? i've got a rigid (brand) vac, so maybe it's not possible? if it is, though, i've got a half-poly'd hardwood floor that still needs a coat or two, but it's been at least 2 months (and probably more like 6 months) from the last poly to now. figure it should probably be sanded again, and if i don't have to rent one of those behemoth sanders from home depot, i'd be just as happy.
posted by msconduct at 11:05 AM on February 9, 2008

Use abrasive pads instead of sandpaper. They're less harsh and should knock the shine down nicely. They're the ones that look like (because they are) scotchbrite scrubby pads.
posted by electroboy at 12:13 PM on February 9, 2008

By way of illustration, I recently bought a new car and found out that when they paint cars with fancy colors (pearl, metallic, etc), the color itself is actually flat. They then go over this with multiple coats of clear coat to produce the shine. For your purposes, the mix of gloss and satin won't be a problem and actually will look better from the clarity of the undercoats as Enroute says.
posted by rhizome at 3:31 PM on February 9, 2008

msconduct writes "how does one hook up a palm sander to a shop vac? i've got a rigid (brand) vac, so maybe it's not possible?"

The vacs are pretty well standardized on the size of the intake port (assuming your hose comes off), it's the sanders that are tricky with all sorts of weird shapes and sizes.

I've got a Porter Cable palm sander with an exhaust port and a couple shop vacs with 1 1/4" and 2" 1/2" hoses (I think; whatever, a large and a small diameter hose). I've never been able to find a coupler to go directly from the hose to the sander (it's port is about 7/8" OD). However the hose from a manual drywall sander (like this one) has an end that _almost_ is small enough. But the hose won't fit on my small vac hose. So I duct taped the two hoses together (pic) and then wrapped the exhaust port on the sander with a few wraps of electrical tape until it fits snugly into the fitting adaptor(pic).

I had the drywall sander already but I'd bet a few minutes in the local Borg plumbing isle will probably turn something up if you can't find an adapter in the vac section that fits your sander. If your sander doesn't have an exhaust port I'd buy a new sander. They are pretty cheap and the lack of dust (both while sanding so you can see the result and in one's home afterwords) is worth it. And you can get a sander that hooks right to your hose.

Also make sure you are moving the sander with the grain of the floor. The 1/4 sheet sanders aren't random orbit and you want the scuffs to go with the grain. Even if you have a RO sander it would still be a good idea.

electroboy writes "Use abrasive pads instead of sandpaper. They're less harsh and should knock the shine down nicely."

If you go with scrubby pads make sure you get a finishing/fine grit pad. They are commonly available in course, medium and fine.

Have fun, I did 4 or 5 coats on 1100 square feet and hand scuffed in between each. I only used the big machine for the original sanding (mostly because the floors were in really bad shape).
posted by Mitheral at 7:43 PM on February 9, 2008