# Oil based thinning



## Bondo (Dec 8, 2007)

Ayuh,..... With acetone, it's such a fast flash off thinner, the paint drys atad quicker,....

Lacquer thinner can usually be used in-place of acetone,.....


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## wptski (Sep 19, 2008)

Bondo said:


> Ayuh,..... With acetone, it's such a fast flash off thinner, the paint drys atad quicker,....
> 
> Lacquer thinner can usually be used in-place of acetone,.....


What about using mineral spirits? Some don't even list what to use for thinning.


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## chrisn (Dec 23, 2007)

What calls for acetone?


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## wptski (Sep 19, 2008)

chrisn said:


> What calls for acetone?


Rustoleum oil based paint.


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## klaatu (Mar 9, 2015)

Uh, acetone is the only VOC compliant solvent readily available in stores that can legally be added to oil based paint. Adding mineral spirits violates the VOC regulations. Mineral spirits will work fine and won't adversely speed up the drying time but you may draw the ire of the VOC black-suit dudes. Actually there is no regulations for what the end user uses as long as it is used by a diy'er on their own property and not for an item for resale. The solvent listed on the can is the only solvent that can be used without raising the "as sold" voc level, as per voc regulations. The paint companies cannot recommend any additive that raises the voc content of the paint. So they resort to listing acetone which would be hell to use when brushing it.


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## wptski (Sep 19, 2008)

klaatu said:


> Uh, acetone is the only VOC compliant solvent readily available in stores that can legally be added to oil based paint. Adding mineral spirits violates the VOC regulations. Mineral spirits will work fine and won't adversely speed up the drying time but you may draw the ire of the VOC black-suit dudes. Actually there is no regulations for what the end user uses as long as it is used by a diy'er on their own property and not for an item for resale. The solvent listed on the can is the only solvent that can be used without raising the "as sold" voc level, as per voc regulations. The paint companies cannot recommend any additive that raises the voc content of the paint. So they resort to listing acetone which would be hell to use when brushing it.


So they will never stated mineral spirits or like some, nothing at all?

I use a respirator when I spray anything. I'd use a organic filter for the acetone if I go that route.

In the car restoration forums, they claim mineral spirits dry too slow. I think they were saying that one or the other reduces sheen.


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## Bondo (Dec 8, 2007)

Ayuh,.... I use xylene to thin Rustoleum for sprayin',....

Brushin', 'n rollin', it goes on, right outa the can,.....


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## ric knows paint (Oct 26, 2011)

wptski said:


> Rustoleum oil based paint.


I'm pretty certain Rustoleum's Oil Base Enamels may be thinned with regular Mineral Spirits - though, I would contact Rustoleum first to confirm. The primary solvent in Rustoleum Rust Stop is Mineral Spirits, and in the Professional line the primary is Aliphatic Hydrocarbons...in both cases, straight Mineral Spirits falls into the primary...VM&P Naptha may also be a suitable reducer.

The reason they recommend thinning with Acetone is to allow for reduction without compromising the VOC output of the host product (Acetone is an "exempt" solvent and therefore = 0 VOC). A manufacturer cannot recommend reducing with a solvent that will knock the product out of VOC compliancy.

I don't like to reduce oil/alkyds with acetone, even though they are compatible. Even though the evaporation rate is very fast, it will NOT accelerate the drying time of an alkyd product - and in many instances, it will actually slow the "dry-through" time, the time for re-coat and the cure "hard" time. DO NOT SUBSTITUTE LACQUER THINNER FOR ACETONE...especially with alkyds. The reasons are many, but the primary issue is the long-term, destructive affect lacquer thinner poses to an oil/alkyd resin...and Rustoleum even specifically mentions not to thin with lacquer thinner.

In this age of VOC's, both awareness and compliancy, it is necessary to understand that solvent chemistries in paint aren't what they once were. To keep oil products VOC compliant (for now, at least), manufacturers are working with some odd combinations of solvent and resin blends to achieve a market-demanded, but compliant, oil based coating. The solvent structure is no longer nothing but petroleum distillates - but now include plant based and engineered solvents, with blends of alcohols and ketones. Not all of these solvents play well together. The same is true for developed resin blends - and the reaction between. This may be why many oil/alkyd products may dry differently than they once did - why they no longer "wet" a surface as they once did - why they smell different (and usually worse) - why a wet-edge isn't as easy to sustain as it once was with alkyds - why, now more than ever, applied thickness and re-coat times are so critical to the proper dry and performance of an alkyd...and on & on & on... I know of one "standard" oil-based product on the market (an agricultural product) that, due to the solvent blend used to stay compliant, mineral spirits may not be used to thin with. Not only because of the VOC (compliancy) issue, but also because the solvent blend (which is largely petro-distillates) will not blend with the safe and mild aliphatic solvents because the film will wrinkle like a raisin if done so, even in small amounts ( I often times reduce this product with MS, then conduct a drawdown just to show the consequence of not following package directions...the drawdown applies like you'd expect, then slowly begins to wrinkle throughout the entire film like a cheap special effect in a low budget sci-fi film)...(now you see why I'm not invited to all that many parties).

Anyway, again I'd probably feel comfortable thinning with Mineral Spirits, but I'd like to hear Rustoleum say, aside from the VOC thing, it's OK to do so. Peace.


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## GottaFixIt (Dec 3, 2010)

I've always used xylene for Rustoleum.


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## wptski (Sep 19, 2008)

Why are you guys using xylene instead?

I asked Rustoleum about using mineral spirits to thin.


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## klaatu (Mar 9, 2015)

Bondo said:


> Ayuh,.... I use xylene to thin Rustoleum for sprayin',....
> 
> Brushin', 'n rollin', it goes on, right outa the can,.....


Xylene would actually be my recommendation, other then it technically being illegal for me to make a recommendation. Xylene is usually the best thinner to use in any rust inhibitive alkyd product.


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## wptski (Sep 19, 2008)

klaatu said:


> Xylene is usually the best thinner to use in any rust inhibitive alkyd product.


Why so?


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## Bondo (Dec 8, 2007)

wptski said:


> Why are you guys using xylene instead?
> 
> I asked Rustoleum about using mineral spirits to thin.


Ayuh,.... I read it somewhere along time ago, before the internet, 'n it _Worked_,....

Ain't seen any reason to change my thinkin',.....

'course, I don't keep up with the latest jibber-jabber from faceless bureaucrats in Washington either,...


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## Nestor_Kelebay (Jun 17, 2008)

I think if this is an alkyd product that you're applying by brush or roller sleeve, then you'd be fine thinning it with mineral spirits.

If you're going to spray this Rustoleum paint, you might want a thinner that evaporates faster so that you can spray on a thicker coat without it sagging on you.

Here's my understanding of the fastest to slowest evaporating solvents that can be used as thinners for alkyd paint:

FASTEST
1. Acetone
2. Toluene
3. Lacquer thinner (which is typically mostly toluene)
4. Xylene
5. Methy Ethyl Ketone (MEK)
6. Mineral Spirits
7. I don't see why it wouldn't be possible to use glycerine as a thinner for alkyd paint.
SLOWEST

And, the above list doesn't include denatured alcohol or methyl hydrate, and I don't see why you couldn't use those as thinners for alkyd paint either.

The only way I see that using acetone as a thinner for alkyd paint makes sense is if you're spraying it, in which case you want the thinner to evaporate rapidly so that your paint doesn't "run" on vertical surfaces.

I'd phone some body shops and see if they've ever used isopropyl alcohol for thinning alkyd spray paint. I've got next to no experience with spray painting, but I'd be willing to try thinning alkyd paint with isopropyl alcohol instead of acetone. I don't see why ANY rapidly evaporating solvent wouldn't work as well as acetone.


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## ric knows paint (Oct 26, 2011)

wptski said:


> Why so?


Don't quote me on this, but I believe that prior to the most recent VOC reformulations, that Rustoleums recommended reducer for their Stop Rust (and probably Professional series) was Xylene. And I'm playing a little mind trivia with myself here, but I seem to remember many rust-inhibitive lines of enamel from other manufacturers often suggested Xylene as the preferred reducer...

You asked "why?" ...and the reasons may be many-fold. Speaking generally, rust-inhibitive enamels are very tough & durable, hard-drying alkyds. Designated for interior & exterior use, they must be able to provide corrosion resistance to surfaces exposed to weather and the most damaging of all elements (sunlight), and still be able to withstand frequent handling, abrasion, impact, grinding, etc. The tougher the resin, the more difficult it may be to dilute with common mineral spirits - thus the need for a recommendation like Xylene. Xylene is a medium strength aromatic solvent, but greater in strength than mineral spirits. As it relates to paint, all solvents will serve as either a "solvent" (dissolves) or "diluent" (dilutes) - unless you're using a non-reactive resin, such as shellac or some lacquers (and others) - your recommended reducer must be able to dilute, without dissolving. Some alkyd resins can't be diluted, thoroughly or completely, with mineral spirits, and need the stronger Xylene as a diluent. Other alkyd resins (interior only products, or perhaps less durable "rust inhibitive" enamels) may be too sensitive to xylene (which may serve as a "solvent" and dissolve the resin) and be better reduced with mineral spirits which dilutes the resin (and dissolves nothing).

It's because of this that it is so necessary to follow manufacturer's directions when reducing a product for spray, or general application. Stronger solvents will absolutely "thin" a product for application, but could dissolve the resin - in that scenario, you may have a dried film that is incapable of providing the type of protection you were expecting....or paid for. Just because it "works" doesn't mean it's the best thing for reducing your product with. If that was the case, just use gasoline to reduce with - it's cheaper and more potent even than Xylene (I'm kidding - don't use gasoline). None of this is to say that an oil/alkyd product, that recommends mineral spirits as a reducer, is a lesser quality than one that recommend Xylene. No determination can be made to the quality simply based on the recommended reducer...

Another reason Xylene may be preferred to mineral spirits is that Xylene may displace moisture than mineral spirits - and be better at delivering the protective paint (or primer) deep into the contours of the surface, minimizing the risk of flash rusting during app or drying. Xylene may also be more tolerant of surface oils or grease at time of application than mineral spirits (don't test this - clean the surface of all oils and grease prior to painting). 

Contrary to those advantages, Xylene has a stronger odor than mineral spirits, and in some instances, Xylene may attack solvent sensitive coatings if applied in a repaint situation...

So...there you go. What did Rustoleum say about using mineral spirits?


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## wptski (Sep 19, 2008)

I watched a video where a guy used automotive windshield washer fluid to thin latex paint.

No reply from Rustoleum on my question yet.


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## GottaFixIt (Dec 3, 2010)

wptski said:


> Why are you guys using xylene instead?


I always thought it was the primary solvent in Rustoleum. Sure smells like it anyway. I checked the MSDS and surprisingly, it says acetone.

I think I'll still use Xylene. I get good results with it and it does a great job at clean up.


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## wptski (Sep 19, 2008)

Nick DIY said:


> I always thought it was the primary solvent in Rustoleum. Sure smells like it anyway. I checked the MSDS and surprisingly, it says acetone.
> 
> I think I'll still use Xylene. I get good results with it and it does a great job at clean up.


Don't the fumes bother you or do you use protection?:devil3:


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## GottaFixIt (Dec 3, 2010)

wptski said:


> Don't the fumes bother you or do you use protection?:devil3:


No doubt, the stuff stinks worse than most other solvents. I do generally have my good ole' 3m 6000 mask on, though.


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## wptski (Sep 19, 2008)

Got a reply.
*****
Thank you for contacting Rust-Oleum Product Support.

We recommend using acetone but you can use mineral spirits if you like. Both solvents will work. Keep in mind that you start at 5% and do not use any greater than 15% for thinning.
*****


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## ric knows paint (Oct 26, 2011)

wptski said:


> I watched a video where a guy used automotive windshield washer fluid to thin latex paint.
> 
> No reply from Rustoleum on my question yet.


yeah...don't do that with the automotive windshield washer fluid. It's not that it won't work, but believe it or not, there is a relatively delicate balance between the components in a can of paint. When dumpster chemists start adding foreign material to paint, that is not recommended by the manufacturer, strange consequences may occur long after the application and drying of the altered product...and these consequences aren't always the good kind.

A person may be tempted to add windshield washer fluid to lower the surface tension of a latex coating - to provide better flow & leveling, and to extend the wet edge of a latex product...and for the same reason some people will add shampoo or creme rinse, dishwashing liquid, anti-freeze, urine (I'm not kidding), denatured alcohol, glycerine, salt-water, powder detergents, etc. etc. etc. to change the working properties of a product. Trouble is, any - or all of these "additives" may mix in fine, with no apparent, or immediately disastrous consequences...but what is often difficult to measure, during application, is the affect these "additives" present to the coalescent process of the coating. 

Proper coalescence (the curing mechanism for latex paints) is a precarious balancing act even when a coating is not altered with foreign material. Cold temps, hot temps, changing temps, high humidity, high winds, direct sunlight, solar flares, presidential debates, cell phone towers and twitter accounts can all cause disruptions to the necessary coalescent process. If a latex coating cannot coalesce (or cure) properly, the film may not gain proper adhesion, stain & block resistance, washability, weatherability, uniform color or touch-up ability...the film may be more susceptible to absorbing airborne dirt and dust into the film, and more likely to support mold & mildew growth. The film may be more prone to surfactant leaching (as y'all have talked about ad nauseam) and color leaching...and may even pose difficulties when attempting to repaint in the future. 

The frustrating part (from a manufacturer's perspective)...(and I'm not a manufacturer)...(not really)...is that when any of these characteristics manifest themselves due to the irresponsible actions of those who don't understand the chemistries of a coating - the paint gets blamed. Always. ...and due to the terrible cost of conducting a true forensic investigation as to why a coating behaved as it did, the consumer - especially the violators will never know why the product didn't perform.

(sigh)...I shall get off my soapbox now - my typing finger has grown weary, and I've become frustrated with the futility of arguing against ignorance and the rebellious refusal of those to simply follow manufacturer's directions...


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## wptski (Sep 19, 2008)

There is a post in some thread here about adding poly to latex with very good results.


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## Nestor_Kelebay (Jun 17, 2008)

wptski said:


> There is a post in some thread here about adding poly to latex with very good results.


I can see putting an alkyd based polyurethane into an alkyd paint and getting good results.

Putting an alkyd based polyurethane into a latex paint is like putting chicken soup into latex paint with the hope of getting very good results. If chicken soup would help, paint companies would sell it as an additive.


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## wptski (Sep 19, 2008)

Nestor_Kelebay said:


> I can see putting an alkyd based polyurethane into an alkyd paint and getting good results.
> 
> Putting an alkyd based polyurethane into a latex paint is like putting chicken soup into latex paint with the hope of getting very good results. If chicken soup would help, paint companies would sell it as an additive.


It was putting water based poly into latex:http://www.diychatroom.com/f4/mixing-polyurethane-clear-coat-sealers-into-paint-23641/index2/


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## ToolSeeker (Sep 19, 2012)

WOW you mean all those words on the back of the can actually mean something. WHO KNEW?


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## chrisn (Dec 23, 2007)

ToolSeeker said:


> WOW you mean all those words on the back of the can actually mean something. WHO KNEW?


You mean to tell me you actually read these?:w00t:


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## cdaniels (Dec 27, 2012)

I still learn after nearly 30 years in the business. We don't use much oil anymore and that's more than ok with me but MS is all I've used to thin any oil with in the last 20 years or so....We used to use a Varsol when it wasn't so hard to get here. The local paint store had it in a 100 gal. drum outside the back of the store. Brought our own container and they would fill it. Now a gal. of thinner costs 13 or 14 bucks here.


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