Paint thinner vs mineral spirits

[Dan Mitchell]

I picked up a can of oil based Varathane polyurethane for a couple maple & walnut tables I built. I have about a quart of mineral spirits on hand for brush cleaning, but figured I'd pick up some additional solvent for this task. Mineral spirits are about $2-$3/gallon more than paint thinner. Both are only labeled "petroleum distillates". Yeah, no kidding. What, if any, is the functional difference between mineral spirits & paint thinner?

TIA

Dan

[Jim Becker]

Unless there is something special about a particular product...paint thinner "is" mineral spirits; at least on the three containers I have in my shop. That said, the low odor version tend to cost a little more, but I prefer them. (I don't use oil based finishes, but do use mineral spirits in the shop for wiping down things)

[Dan Mitchell]

(I don't use oil based finishes, but do use mineral spirits in the shop for wiping down things)

Thanks for the reply. Now you have me concerned about the use of the oil-based poly to begin with! I would probably have preferred the water based, if for no other reason than easier clean up, but I want something that is going to bring out the grain, especially of the maple base pieces, while giving a sufficiently hard finish for the top of a relatively high traffic table. All without require umpteen different products & steps, of course! :D Does anything else spring to mind which would fulfill these requirements? Haven't opened the Varathane yet (or used the $12 natural bristle brush, or the $12 paint thinnner) so if there's something preferable, I'd love to hear about it at this point.

Thanks again

Dan

[Jim Rimmer]

http://www.sawmillcreek.org/showthread.php?t=117467

Check out this thread. I asked the same question a while back because I was convinced in my own mind that mineral spirits and paint thinner are the same.

[Dan Mitchell]

Thanks Jim, I actually saw that post right after I posted mine & the Googled "Mineral spirits vs paint thinner". Guess I got my steps a little out of order on this one :D

[Jim Becker]

Thanks for the reply. Now you have me concerned about the use of the oil-based poly to begin with! I would probably have preferred the water based, if for no other reason than easier clean up, but I want something that is going to bring out the grain, especially of the maple base pieces, while giving a sufficiently hard finish for the top of a relatively high traffic table.

Umm...I don't use any kind of "poly", for the most part. Polyurethane is wonderful for floors because it was designed for increased abrasion resistance in that setting, but is not ideal for furniture. For an oil based finish, a non-poly alkyd resin varnish (Pratt & Lambert #38, for example) or phenolic resin varnish (Waterlox, for example) would be my preference. Either of these varnish types will bring out figure like any oil based finish will. As to hardness, poly is NOT a hard finish; to the contrary, it's a softer finish than non-poly varnish due to the abrasion resistance properties...which also means it's harder to polish to a particular sheen since that is an abrasive process.

Water borne "poly" is simply an acrylic finish with a little polyurethane resin added. The only one I've used is Minwax Polycrylic and it's an ok finish and readily available. There are much better water borne products available...you'll often see them mentioned in threads here. For the record, I use Target Coatings (http://www.targetcoatings.com) EM6000 most of the time.

Of course, those of us who use water borne products (which typically add little color) also tend to use some BLO and seal with de-waxed shellac before top-coating. That brings out the figure but insures that the finish will properly adhere to the workpiece.

The one thing that poly has going for it is...marketing. When you look at the stocked shelves at the 'borg and read the ads, you are lead to believe it's the "best thing since sliced bread". That said, the product you bought is perfectly fine to use. It will look good and is easy to apply. Just be sure you lightly abrade the surface between coats if more than a few hours pass between them...poly doesn't like to stick to itself and needs a little "tooth" brought by some gentle 320 grit sanding between coats.

[Dan Mitchell]

For the record, I use Target Coatings (http://www.targetcoatings.com) EM6000 most of the time.

Of course, those of us who use water borne products (which typically add little color) also tend to use some BLO and seal with de-waxed shellac before top-coating. That brings out the figure but insures that the finish will properly adhere to the workpiece.

Jim - Thanks for the info. So, in brief, you would apply Boiled Linseed oil, followed by de-waxed shellac, followed by Target EM6000? I'm pretty new at finishing & need specifics, is there a particular make & model of BLO & de-waxed shellac you'd recommend? Do you generally sand between the applications of these various coatings, and to what grit? What type of application do you suggest (I have no spray equipment at the moment, so, natural or synthetic brushes, rags, at which points etc.) Again, the tables are a walnut top on a hard maple base. If you could give me a brief step-by-step I sure would appreciate it, sorry for being so "needy" :D

Dan

Here's a somewhat blurry pic of one of the tables, for "inspiration" :D

[Jim Becker]

The BLO can be the cheap version from the 'borg...there is no point in spending a lot of money on it. I tend to also use Zinnser SealCoat for the dewaxed shellac since I use so much of it and it saves time from mixing my own from flakes. (Only the SealCoat is de-waxed; the other two they sell at retail are waxy and you don't want that under both water bornes and anything containing polyurethane) But if I wanted a darker color shellac, I'd need to use the flakes.

The BLO just gets wiped on with a lint-free towel or rag; let it set for a bit and then wipe of any excess. Let it cure for a day or two before proceeding with the shellac. (Although I'll admit to same-day coating/sealing on some projects) Be really careful with your rags. Do not throw them into the trash--they can spontaneously combust and burn your shop/house down! Find a tree somewhere, put a nice big nail on it and hang the rag over said nail to blow in the breeze until the oil cures. You can then put it in your trash can.

For small projects, just get a spray bomb of Zinsser shellac. It's also dewaxed and easy to apply. Brushing shellac should be done with a high quality brush and you really need to practice...get it on with a wet edge, level with a quick stroke or two and DO NOT revisit areas you already brushed.

EM6000 is usually sprayed but it can be brushed if you want to. Use a good quality synthetic brush and remember it will dry relatively fast...you can't work it like you can an oil based finish. I suggest you get a quart of Minwax Polycrylic and practice with that...it will be similar in brush application.

As always, do your complete finishing regimen on scrap from your project before you proceed to do the real project.

[Neal Clayton]

and on the topic of the waterlox, or other such varnishes, if you choose to go that route, they are really pretty newbie proof with brushing, especially if you want a satin sheen.

they level exceptionally well regardless of the application method, and stick well enough to be applied to vertical surfaces as long as you don't put them on too thick.

downside is drying time, it'll take a day to a day and a half to dry to the touch, and 3 weeks plus to cure, during which time they'll still stink.

but i agree with jim, polyurethane isn't for furniture. buy a few lacquers and varnishes and various colors of shellac when you have some time and play with them to figure out what you like.