# Last coat of Satin Polyurethane



## ChiknNutz (Apr 22, 2011)

I am in the process of applying poly to a stained oak kitchen island. Per the directions, they recommend three (3) coats of poly. I have a applied up to two coats so far on various pcs (due to having to let one side dry before moving on the other side). The issue I am currently experiencing is getting a fair amount of "dust nibs" and/or bubbles here and there. Now I have a pretty clean shop (not doubling as a garage) and have been pretty darn careful about not over-working the poly. I don't shake it, I stir it gently and then apply with a good quality Purdy brush...again, not over-working it. I still seems to find imperfections in the finish, quite a few really (at least to me). While I can and do gently sand them down (currently doing so with 200 grit between coats), my main concern is how am I going to get the final coat to come out as flawlessly as possible? I am using a Varathane oil-based Satin Polyurethane. In a couple of test areas, I've tried sanding with 1000 grit, but that seems too coarse and overly dulls the finish...but not coarse enough to adequately remove the imperfections. Looking for guidance here as I am a relative newbie when it comes to interior finishing. Thank you for any feedback.


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## Rick Mosher (Feb 26, 2009)

For the doors and shelves just make a drying rack like this one. Put a sheet of cardboard or wood a little bigger than your doors on top and as you brush the final coat on each door place it in the rack . Start from the top and work your way down so you don't knock any dust into the wet finish. Each door will protect the one under it from dust and you will have a much smoother finish. (Don't walk around the shop when you have finished the last door as you kick up dust when you walk around.)


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## Steve Neul (Sep 2, 2011)

Most of the time when you get dust in the finish it's comming off your clothes. When you spray the finish coat you should thoroughly blow the dust off yourself too. When I spray polyurethane, I spray it and leave the building until it is dry to touch.


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## ChiknNutz (Apr 22, 2011)

I applied another coat last night to various pcs, some were first coats, some 2nd coats. The first coats all seem to be kinda rough and subsequent coats better. Still, even after being what I think is really really careful, I am still seeing some blemishes this morning in the 2nd coats. Yes, I will sand those out and apply another coat, but my concern still lies with the last coat which I am sure will produce at least a few blemishes (maybe I am just too pessimistic). Would carefully using a small hand plane work to take off some of these little nibs and high spots, hoping to preserve the sheen of the satin finish?


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## Fred Hargis (Apr 28, 2012)

Consider making your last coat a wiping varnish coat. Thin the varnish you have about 50% with paint thinner, then use a lint free cloth to wipe it on ( I use those blue paper shop towels you can get anywhere). The thinned varnish will tack up much quicker, making the dust that lands on it less of a problem.


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## Rick C. (Dec 17, 2008)

I've had the same problems. Now I ALWAYS thin oil base poly with mineral spirits, yes it's thinner and takes a couple more coats, but it dries much faster, never had a bubble problem and there isn't enough time for the dust to get in the finish. I mix mine 50-50, and wipe it on. You can try less mineral spirits and do what you're comfortable with.


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## ChiknNutz (Apr 22, 2011)

Thanks for the tips. I was just going by the directions on the can and it states to use it un-thinned. Makes sense to me to thin it so it can dry faster.


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## Rick C. (Dec 17, 2008)

Instructions do say not to thin, but that is due to gov't regulations. I've never heard of using paint thinner with oil base poly, may work fine. Mineral spirits are already in the poly, and not as volatile as paint thinner.


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## rayking49 (Nov 6, 2011)

I lightly sand between coats, and by the third or fourth if I go that far it is nice and smooth. I use 220 or 320 to sand. Then wipe off with a mineral spirit dampened rag, let dry then apply next coat of poly. I need to try the thinning too, never tried that yet.


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## cabinetman (Jul 5, 2007)

At a minimum, I would use mineral spirits instead of paint thinner. Mineral spirits is more refined than paint thinner. For a faster dry use VM&P Naptha, instead of mineral spirits. You might also use a spray bottle and wet the floor with water to hold down the dust. If you blow anything off, do it far away from your finishing area.









 







.


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## phinds (Mar 25, 2009)

With poly, I've always had much better luck with wiping on (with a fresh, clean paper towel) than brushing on, but of course I don't do large items and I guess that would be a pain if you were doing a lot of it.

Wiping gives a thinner layer, thus no bubbles, but requires more coats.


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## ChiknNutz (Apr 22, 2011)

I am not getting any brush marks, but I get the fact that wiping on puts on a thinner layer. I am not sure that dust is the primary issue here, the blemishes almost look like contaminants within the Poly, or the Poly has "bunched up" enough to cause a little sharp peak here and there. I see no contaminants in the can or the brush, but they could be there and I am just not seeing them for some reason. In any case, I think I will try thinning down with Mineral Spirits and see how that goes.

I wonder if the problem is that I have been using Paint Thinner to clean the brush, rather than Mineral Spirits. I also dip the brush in Paint Thinner and shake it out really well before my first dip in the poly...could the paint thinner be causing this? I generally do this with water for water-based finishes too.


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## Dominick (May 2, 2011)

cabinetman said:


> At a minimum, I would use mineral spirits instead of paint thinner. Mineral spirits is more refined than paint thinner. For a faster dry use VM&P Naptha, instead of mineral spirits. You might also use a spray bottle and wet the floor with water to hold down the dust. If you blow anything off, do it far away from your finishing area.
> 
> 
> 
> ...


+1 with cabby on getting the floor wet where your working. I've had same problems with dust collecting on the surface. On your final coat make sure it's dust free. Leave the room for a bit, then come back and wipe it off again then put your last coat. By then any dust in the shop/garage may have settled.


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## Fred Hargis (Apr 28, 2012)

ChiknNutz said:


> I wonder if the problem is that I have been using Paint Thinner to clean the brush, rather than Mineral Spirits. I also dip the brush in Paint Thinner and shake it out really well before my first dip in the poly...could the paint thinner be causing this? I generally do this with water for water-based finishes too.


No, that's not the problem. You actually should dip the brush in the appropriate thinner before brushing, makes cleaning easier, among other things. I would bet that none of this is due to paint thinner versus MS, either.


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## phinds (Mar 25, 2009)

Also keep in mind that poly has a relatively short shelf life so you may be using some that is past its effective "use by" date, which I find to be about 6 months after I first open the can, maybe a little longer if I remember to stir vigorously every time I open the can.


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## jodasm (Oct 25, 2012)

By some filters from the paint shop some fine ones shaped like a cone and strain your poly could be old


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## ChiknNutz (Apr 22, 2011)

jodasm1977 said:


> By some filters from the paint shop some fine ones shaped like a cone and strain your poly could be old


Will do, I have some already. Thanks for the reminder.


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## Da Aardvark (Oct 11, 2012)

I have a similar problem with dust and bugs. 
I live with it and in the end will sand down to 800grit and then start hand rubbing with a slurry of pumice powder w/ water rub to bring up a satin , and to go further us a slurry of rotten stone which will bring up even to a gloss. As you rub and wash down, you can choose the sheen you want.
By the way, I don't use a brush on large areas. I spray coat.


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## ChiknNutz (Apr 22, 2011)

Seems like no matter how thick or thin the poly is, filtered or not, sterile air and all, I still seem to get "nibs" in the finish. The majority of these nibs are not contaminants as best as I can tell. Is this just the nature of poly? I was talking with a guy the other day that has started to get into making slab furniture and he is using a water-based lacquer that dries in 30 mins or less (sprayed with a Harbor Freight HVLP gun). He's able to get 4 or 5 coats on all surfaces in a day. I've been applying poly for a few weeks now as I have to let it dry for like 8 hrs before it's dry enough to mess with so I can sand and apply another coat. Granted, my shop is colder than I'd like at 55 degrees or so, but come on! After the first can that was a bit dated, I've been thru two more quarts of the stuff, so it's not that.

Not sure if I'll ever use Poly again on a project like this where there's a gob of surfaces to apply to.


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## Rick Mosher (Feb 26, 2009)

Just for giggles try an experiment. Cut a sample in half and put a final coat on both and immediately put one under a sheet of cardboard with 2 " space and leave the other one out in the air to dry. See if it makes a difference. Share your results with us.:yes:


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## Da Aardvark (Oct 11, 2012)

I don't mess with dealing in pristine spraying conditions. I can't. My garage isn't set up for it. 
Once a coat or 3 is sprayed, I let it dry overnight and sand it with 600, 800, and then hand rub with pumice then rotten stone.
No nibs and I then can choose the sheen I want.


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## ChiknNutz (Apr 22, 2011)

Rick Mosher said:


> Just for giggles try an experiment. Cut a sample in half and put a final coat on both and immediately put one under a sheet of cardboard with 2 " space and leave the other one out in the air to dry. See if it makes a difference. Share your results with us.:yes:


I did this and found the results after it dried to be a bit better, but not one that I would consider blemish-free. Perhaps I am expecting too much with less than ideal conditions. Is it customary to have to work the finish a bit even after the final coat, as 'Da Aardvark' does?


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## woodnthings (Jan 24, 2009)

*Sounds crazy, but it works!*



ChiknNutz said:


> I am in the process of applying poly to a stained oak kitchen island. Per the directions, they recommend three (3) coats of poly. I have a applied up to two coats so far on various pcs (due to having to let one side dry before moving on the other side). The issue I am currently experiencing is getting a fair amount of "dust nibs" and/or bubbles here and there. Now I have a pretty clean shop (not doubling as a garage) and have been pretty darn careful about not over-working the poly. I don't shake it, I stir it gently and then apply with a good quality Purdy brush...again, not over-working it. I still seems to find imperfections in the finish, quite a few really (at least to me). While I can and do gently sand them down (currently doing so with 200 grit between coats), my main concern is how am I going to get the final coat to come out as flawlessly as possible? I am using a Varathane oil-based Satin Polyurethane. In a couple of test areas, I've tried sanding with 1000 grit, but that seems too coarse and overly dulls the finish...but not coarse enough to adequately remove the imperfections. Looking for guidance here as I am a relative newbie when it comes to interior finishing. Thank you for any feedback.


When I sprayed the Fast Dry Min Wax poly on the Murphy Chairs, I had the same problem...little dust nubs. I used a cabinet scraper, rather than sanding. I gently dragged the scraper over the top of the surface and amazingly the finish turned smooth. Try it in an inconspicuous place and see if you like what you get. :smile:

http://www.woodworkingtalk.com/f9/what-chairs-these-39917/


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## ChiknNutz (Apr 22, 2011)

Thanks for the tip about the cabinet scraper, I'll give that a shot!


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