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DIY wiping varnish formula

10K views 17 replies 13 participants last post by  jw2170  
#1 ·
Hi all, looking for a little clarification on 2 points.

Some time back I ran accross a reference to making wiping varnish by thinning polyurethane 50%.

I recently did this using the thinners the manufacturer recommended, mineral turpentine. I've done a couple of jobs using both satin and gloss polyurethane with good results although the gloss had a slightly more subdued finish than I expected.

I then found that the original instructions I'd seen said to thin with mineral spirits.

First of all I can't say I've seen mineral spirits in the shops, not that I was looking, is it called something else down here ?

Secondly, before I run out and start adding to my collection of chemicals, can someone please tell me what practical difference, if any, there would be by using turps or mineral spirits.

Mark
 
#2 ·
there are 2 differences mineral spirits (also called mineral turps, but really isn't as all turpentine is made for tree sap usually pine) if you use too much mineral spirits the binders in your paint varnish whatever won't work right. this might (i am not sure) because spirits dry way faster than turps. which is the 2nd thing that I know about the 2 is the drying time difference. this probably isn't much help but I tried to remember what my dad said about the 2 and this is the only things that stick out in my mind. later biloxi tom
"DO NOT have a good day, have a wild and wonderful one!
 
#3 ·
Turps vs Spirits

Don't know about "down there" but up here we have real turpentine (tree sap product) and mineral spirits (frequently marketed as Varsol. It's a petroleum product.) As far as I know Varsol and mineral spirits are the same thing (I could be wrong, and frequently am) There is also paint thinner which is what I think you are thinking of re: mineral spirits. If this makes any sense.
I would stay away from artificial turpentine.
Good luck, David
 
#4 ·
Hi Mark - to get really confused, do a Google search! For what it's worth, here in SA we have Mineral Turpentine, which I suspect is the same as Mineral Spirits, a petroleum distillate, and then we have Genuine Turpentine, which is a lot more expensive being a tree extract product, and used extensively by artists using oil paints. This might be worth trying, to achieve a better finish.
Rob
 
#13 ·
Turpentine is supposed to be a natural product, but I do believe that mineral spirits is the less toxic of the two - turpentine is supposed to be a lot easier to get into your body via skin...

As for odorless MS, I believe this is usually just a higher grade MS with less odd ball hydrochemicals in it. It's not a watered down solvent, just more pure, with the side effect of also being less stinky!

Anyway, I pretty much always use odorless MS. Tried turpentine once, smelt just awful and the odor hung around for a long time.
 
#7 ·
You might try mixing with boiled linseed oil. It works well for me as a wiping varnish. I've also used a product called Watco to mix with both varnish or poly. Also works well.
 
#9 ·
Hi Mark - hopefully, the links have clarified the differences in terminology used in various parts of the world for these products!

I've used 2 'homemade' clear finishes over the years, i.e. the 'wiping varnish' concoction using 1/2 poly (or varnish) & 1/2 solvent (mineral spirits or naphtha, the latter another petroleum/gas distillate) - I prefer the naphtha for its faster drying time, but a personal choice.

The other uses the 'thirds rule', i.e. 1/3 poly (or varnish), 1/3 MS or naphtha, and 1/3 BLO (boiled linseed oil, which BTW is NOT boiled) - this is a common formula that has been around for years. If I'm doing a 'wipe on' clear finish w/ this material, I would typically use it for just the first coat (not sure the BLO penetrates much w/ additional coats & I don't like rags w/ BLO laying around the shop!) and then switch to the simpler wiping finish.

Good luck w/ your projects - Dave :)
 
#12 ·
Hello Mark,

What I am finding here, just outside of San Francisco, is that most of the big box stores are carrying "odorless mineral spirits". I use this for cleaning my hands, and tools. I have not used it to "thin" polyurethane.

I have this theory is that the Environmental Protection Agency is making it harder for woodworkers to get solvents that work "fast" because it is BAD for the environment. Odorless Mineral Spirits is a petroleum based product. This will "priced" with the fluctuating GASOLINE PRICES ( I just paid $ 4.22 per gallon in SF, Ca..). I can only buy this in 1 gallon units, and smaller.

Best wishes from the Peoples Republic of California, where the "people" are nuts, and the men are fruits. ( Did I get that mixed up ? Thank my Kalifornia eDuCation. I are a Kollege Graduate ! University of California )

Neil
 
#16 ·
Mark,

I want to add to the confusion.....

I thought we called "mineral spirits" ......metho.......(metholated spirits).:blink:
 
#18 ·
Found it......

While wiping down my new table saw today, I happened to check the bottle.

:sarcastic:
 

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