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Little tip for polyurethane top coat

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Forum topic by nickbatz posted 05-14-2018 02:41 AM 871 views 0 times favorited 21 replies Add to Favorites Watch
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nickbatz

146 posts in 162 days


05-14-2018 02:41 AM

Topic tags/keywords: finishing

In case it’s useful, here’s my technique for poly top coat over spray-painted oak ply:

Two sponges, one for applying the finish and a second one for drying where it pools/smoothing it out so you get really thin coats.

Eventually the dry sponge soaks up enough finish to become the wet one, and then you use it and grab the next dry one. Sponges are a Harbor Freight item – they’re disposable and work just as well as more expensive ones… although I store them in Ziplock bags in between coats.

Also, they tell you to sand with 220 in between coats. Too aggressive. I just leave it alone unless something needs cleaning up (like a drip or something).


21 replies so far

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therealSteveN

909 posts in 656 days


#1 posted 05-17-2018 07:10 AM

Thanks for posting

I had seen something on the sponges before and was going to try it out. Now that it’s staying warm, I may hit it soon.

-- Think safe, be safe

View LesB's profile

LesB

1790 posts in 3525 days


#2 posted 05-17-2018 04:34 PM

I may be missing something here. Why not just use a “wipe on” poly to begin with?

-- Les B, Oregon

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Rich

3340 posts in 672 days


#3 posted 05-17-2018 04:57 PM

Why not spray it on since you’ve sprayed paint already? Nothing can beat the finish you can get with a spray gun.

Also, I gotta ask why you’re spray painting oak ply? Why not just go with less expensive plywood?

The sponge thing sounds weird. I won’t criticize it because I’ve never tried it, but there’s nothing in my years of finishing that makes me think it will be any better than just a wipe on, and definitely not as smooth as a spray.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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nickbatz

146 posts in 162 days


#4 posted 05-17-2018 05:15 PM

LesB, wipe-on poly is a slightly different thing, at least the oil-modified stuff I have, but I use two rags for it and other wipe-on finish – similar idea, with a wet one and a dry one.

Rich, I don’t have a spray gun, but maybe I’ll try spraying poly in the future. The reason I used oak ply is that you can still see the grain through the spray paint, and it looks really good. It’s a very different look from cheaper plywood, and it was worth the extra $25 to me.

I should add that I did another oak ply desk with black gel stain, and eventually looked great, but took too much work… and didn’t look as good as the spray paint I used on this one. However, I used black gel stain on the (high grade) D fir leg assemblies for this desk, and it looks just gorgeous. The result is actually not black, it’s very dark brown. But I won’t use gel or any other stain on oak ply going forward; gonna either be spray paint or Watco oil (which I prefer to either, but what can you do – if someone wants black, gotta make it black).

Note that I’m not saying this is the way everyone has to do it, just posting one technique that worked very well for me. If it’s not helpful to you, no problem!

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Rich

3340 posts in 672 days


#5 posted 05-17-2018 05:51 PM


Note that I m not saying this is the way everyone has to do it, just posting one technique that worked very well for me. If it s not helpful to you, no problem!

- nickbatz

That’s why I said I wouldn’t criticize it because I’ve never tried it. That’s one of my pet peeves on here — people who “just know.” We even had an entire thread about the phenomenon titled “Without personal experience.”

A quick aside: I’d been on LJ for just a few weeks and posted a sanding tip that works for me. One of the veterans replied that “that won’t work.” Annoyed, I asked him if he had just gone to the shop and tried it. His reply was that he has 35 years of experience and doesn’t have to try it to know it won’t work. What a dope. It was OK though, I explained to him that I have over fifty years of experience and that shut him up temporarily. Years of experience is meaningless anyway, someone can spend 35 or 50 years woodworking and still suck at it…lol

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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Aj2

1583 posts in 1880 days


#6 posted 05-17-2018 06:06 PM

I hate polyurethane finishes. It’s a plastic sticky mess.

-- Aj

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nickbatz

146 posts in 162 days


#7 posted 05-17-2018 07:48 PM

Rich, we’re on the same page – except that woodworking is a new sport for me, an outgrowth of a 12-year-old side business. I was making detailed drawings for a shop to build a product I was selling (a specialized desk for composers), then revisited the design and figured out how to make them myself (although the latest one is totally custom). In other words, I’m having way too much fun to bother having an ego over finishing wood!

Aj2, what do you use for a topcoat? My preference is for oil/varnish on its own, or – if I were more ambitious than I am and wanted to learn how to do a French polish – shellac. But this desk had to be black and very durable… and while I admit I was afraid of using polyurethane exactly because I didn’t want it to look plastic, it actually turned out really nice. Not just nice, really nice, meaning I satisfied the most difficult person to satisfy: myself.

View MrUnix's profile

MrUnix

6845 posts in 2281 days


#8 posted 05-17-2018 07:55 PM

With wipe on poly, you can get a wide range of looks from natural hand rubbed oil to a super gloss finish. And it’s for the most part foolproof.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View nickbatz's profile

nickbatz

146 posts in 162 days


#9 posted 05-17-2018 07:56 PM

On top of paint, Brad?

If so, will have to use that next time. What specific products?

View MrUnix's profile

MrUnix

6845 posts in 2281 days


#10 posted 05-17-2018 08:00 PM

On top of paint, Brad?
If so, will have to use that next time. What specific products?
- nickbatz

No different than what you are doing on top of paint – except putting it on thinner and without the need for sponges (old cut up t-shirts work just fine). Probably a lot quicker as well, as the coats typically dry within 30 minutes or so. Just cut the poly 50/50 with mineral spirits.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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nickbatz

146 posts in 162 days


#11 posted 05-17-2018 11:56 PM

So it has to be an oil-based poly, right?

Also, no mineral spirits in most of CA (preserving the ozone). But there are substitutes.

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MrUnix

6845 posts in 2281 days


#12 posted 05-18-2018 12:02 AM

So it has to be an oil-based poly, right?
Also, no mineral spirits in most of CA (preserving the ozone). But there are substitutes.
- nickbatz

Uggg… yeah, oil based… and there is no real substitute on the market for mineral spirits. The ‘green’ low VOC stuff they are pushing is pure garbage. If it says to ‘shake well’ before use, run away screaming.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Charlie H.'s profile

Charlie H.

252 posts in 732 days


#13 posted 05-18-2018 01:01 AM

I use polyurethane quite often and apply it with folded bounty paper towels in the same manner described for using the sponges.
This method of application works well for me.
I have no reason to doubt sponges would work too.
Between coats I use very fine steel wool to remove any dust nibs.
I have been experimenting with red, gray, and white scotch brite pads instead of steel wool.
Not sure I think they are a good substitute but I bought lots of them so they are going to get used until they are gone.
Like other built up film finishes polyurethane can produce many different looks.
I typically knock the gloss off it with steel wool before applying the wax.

-- Regards, Charlie in Rowlett, TX --------I talk to myself, because sometimes I need expert advice.---------

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nickbatz

146 posts in 162 days


#14 posted 05-18-2018 01:08 AM

Folded Bounty paper towels! Okay, I have to try that.

I’ll also try steel wool. All three cans of polyurethane I have – two water-based Minwax ones and an oil-modified Zar – say not to use steel wool. My guess is that they just don’t want hairs, but I’ll bet you can get rid of those if you’re careful, and in my experience steel wool is much better in between coats of finish than sandpaper. It smoothes over rough stuff rather than removing the finish the way sandpaper does.

I actually have something like Scotch-Brite pads for my finishing sander, but they’re not abrasive enough – the other extreme.

View MrUnix's profile

MrUnix

6845 posts in 2281 days


#15 posted 05-18-2018 01:12 AM

Water based poly does not recommend steel wool because any residue left behind can/will rust.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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