# How many coats of polyurethane to get the "glassy" appearance? **URL:** \ **Category:** Factual Questions\ **Created:** [July 22, 2003, 4:28pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172 "2003-07-22T16:28:07Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [July 22, 2003, 4:28pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/1 "2003-07-22T16:28:07Z")
I finaly figured out how to sand this old antique table I picked up. It had a lot of mold on it and I couldn’t get it off with the bnelt sander I had… so I brought it down to a mill down the road and for 5 bucks it looks like new… Now for the Poly. I have two coats of a Pecan poly on and it looks nice. I want to put more coats of clear on it for a good glassy sheen… It’s still a tad grainy yet… So how many should it take. I just want to plan for it. Are we talking like 10 coats or just another 2? Anyone have an idea? ---
**Author:** ![DeVena](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@DeVena](https://boards.straightdope.com/u/DeVena)\ **Post date:** [July 22, 2003, 4:42pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/2 "2003-07-22T16:42:30Z")
I have a friend who makes furniture, and one of his trademarks is the thick, glossy finish. He puts 5 to 7 coats of poly on everything, allowing a full dry between. He made the mantle for my parents house from a huge cedar tree, amazing, and it has that glassy finish. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [July 22, 2003, 5:03pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/3 "2003-07-22T17:03:38Z")
It usually takes me 3 coats on oak. The surface ends up smooth, but still vaguely wood-like. Too many, and you end up with that plasticy look. That’s all right, if it’s what you’re going for, but it does rather clash with the lines of many antiques. ---
**Author:** ![Labdad](https://avatars.discourse-cdn.com/v4/letter/l/439d5e/32.png) [@Labdad](https://boards.straightdope.com/u/Labdad)\ **Post date:** [July 22, 2003, 5:07pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/4 "2003-07-22T17:07:44Z")
I have found the key is sanding between coats. Before you put any more poly on it, sand the whole thing thoroughly with 220 grit sandpaper. After the next coat dries, switch to 320 grit and go over the whole thing again. Apply another coat, then go over the whole thing with 400 grit. (Be sure to wipe the whole piece down with a tack cloth each time after sanding to remove all the dust before applying another coat.) You can get the finish up to the quality of fine laquer by using progressively higher grits between coats. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [July 22, 2003, 5:32pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/5 "2003-07-22T17:32:22Z")
Well, first things first. BUY Hi Gloss polyurethane, because it comes it reg, satin, semi and hi-gloss. Visit: [WWW.minwax.com](http://WWW.minwax.com), because their site is very very helpful. Use the exact sandpaper the product says to. Do not follow old-timer advice for new polys. Also, conisder buying marine grade polyurethane, especially if there is any chance the item will see UV rays or moisture. And then go 5-7 coats with marine grade poly. Helmsman is Minwax’s brand of marine grade poly. For a bar top (just made a custom maple bar) you are looking at 5 coats. Sides can do with 3. Most go 7 on top, 5 on the sides. I’d say a table would be similar. And Minwax does not recommend tack clothes. ---
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [July 22, 2003, 5:32pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/6 "2003-07-22T17:32:23Z")
Well I have been using #000 steel wool in between coats. And it has proved good so far. I’ve also been allowing 24 hours between coats because the weather here in CT is god-awfully humid lately. I’ll try two more coats with clear poly and see what we get. That should work. Thanks folks… The table looks really nice. I love my dremmel. ---
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [July 22, 2003, 5:47pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/7 "2003-07-22T17:47:43Z")
Why no tack cloth with minwax… I’m using minwax Polyshades (pecan) and I’ve already used a tack cloth on it. It didn’t look like it was harmed… don’t freak me out philster… ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [July 22, 2003, 5:56pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/8 "2003-07-22T17:56:44Z")
Here are the directions, from the label. (now my instruction sheet I grabbed in addition specifically warned against a tack cloth, and their label directions mention a cloth dampened with mineral spirits to clean dust up after sanding- not a tack cloth. I believe the tack can stay behind and prevent bonding of layers) Minwax is very helpful…if they wanted you to use a tack cloth, they’d say so. > **[Minwax Helmsman Spar Urethane - Exterior Polyurethane Finish | Minwax](https://www.minwax.com/wood-products/clear-protective-finishes/interior-exterior/minwax-helmsman-spar-urethane)** > > Helmsman Spar Urethane is a clear finish that offers protection for interior or exterior wood exposed to sunlight, water and temperature changes. ---
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [July 22, 2003, 6:15pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/9 "2003-07-22T18:15:36Z")
Ok. I’m not sure why I would want to use mineral spirits directly on the table. I’d think that would compromise the integrity of the poly already on it. I do have 220 grit and 400 at the house so I’ll use that. We’ll see how it goes after that. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [July 22, 2003, 6:27pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/10 "2003-07-22T18:27:29Z")
double check the Polyshade directions. While both Polyshades and Polyurethane call for clean up with mineral spirits, Polyshades sanding needs are diiferent. Polyshades: APPLICATION Two coats are recommended for maximum beauty and protection. Brush on a THIN, EVEN COAT in the direction of the grain. Be sure to maintain a wet edge. Let dry 8 hours or more, then rub surface with fine steel wool (grade 000 and finer). Remove all dust. Brush on a second THIN coat. You may apply more than two coats if you want to deepen the color. ---
**Author:** ![DiLLiGaF](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@DiLLiGaF](https://boards.straightdope.com/u/DiLLiGaF)\ **Post date:** [July 22, 2003, 6:47pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/11 "2003-07-22T18:47:35Z")
> [@](#): > > \*Originally posted by Phlosphr \* > \*\* I do have 220 grit and 400 at the house so I’ll use that. We’ll see how it goes after that. \*\* I would just use the 400 grit if you already have a few coats of finish on it already. The 220 is really too rough for finish work. And watch those edges when sanding down finish! It is really easy to go through the finish and stain on edges and then you have a mess. FTR, I ran a refinishing business for 10 years and have done lots and lots of furniture. I always bought big sleaves of 320 wet/dry paper for my finishing needs, if I didn’t want it that course I would just fold it over onto itself and rub it together a little bit to ‘take the edge’ off. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [July 22, 2003, 7:01pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/12 "2003-07-22T19:01:23Z")
Well, my advice, which is already too late, is not to use steel wool with oak. When you steel wool something, you leave behind little bits of metal. If they get wet, they react with the tannic acid in the oak and form black spots. Most people recommend using 3M pads (essentially kitchen scrubbers) instead. May be no harm done, given that you’re using a pretty impermeable poly instead of an oil finish, but it is humid where you are, so the moisture could cause problems. As for the finish, pretty much what people have said. Some people will suggest using a wood filler to fill in the grain of the oak before finishing if you really want that glass-like finish, but again, that’s mostly necessary for penetrating finishes like oil, rather than poly. ---
**Author:** ![Phlosphr](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Phlosphr](https://boards.straightdope.com/u/Phlosphr)\ **Post date:** [July 23, 2003, 1:22pm UTC](https://boards.straightdope.com/t/how-many-coats-of-polyurethane-to-get-the-glassy-appearance/190172/13 "2003-07-23T13:22:54Z")
I steel wooled the with #000 wool yesterday then layed a thick layer of clear high gloss polyshade on it. It looks great. I’m debating on one more coat. three is looking pretty good… We’ll see.