# Naptha or Japan Drier



## Tundra02 (Oct 22, 2014)

I have a job coming up in the spring and have to paint 3 exterior doors. The customer insists on using Rust-Oleum oil on the doors ( Last painted 12 years ago and look great.Just wants to change color .). I want to speed up the drying of the oil and was wondering which would work faster the Naptha or Japan drier.


----------



## CApainter (Jun 29, 2007)

Japan Drier ( a siccative) actually cures oils through a chemical crosslinking process. A Naptha solvent is going to just evaporate quickly, creating a film surface dryness, but not necessarily a complete coalescing of the paint film. In other words, the Japan Drier's molecular structure acts as a catalyst for oil base paints, accelerating curing through out the coating film, where as the solvent is basically a fast evaporating reducer.


----------



## PACman (Oct 24, 2014)

It also depends on what "flash" of naptha you are thinking of using. The dry time is actually backwards to what you would think it is, i.e. 150 flash naptha dries slower than 100 flash does. In fact if i remember correctly (which i admit has been an issue lately) even VM&P naptha actually dries slower than mineral spirits does, but it has a stronger solvent strength. Also if the maximum rust inhibitive properties of the alkyd Rustoleum are to be maintained then Xylene must be used as a reducer.


----------



## Tundra02 (Oct 22, 2014)

Japan Drier it is


----------



## Woodco (Nov 19, 2016)

Its important to note, that a lot of rustoleum oils require Acetone as a thinner, which also speeds up the solvent drying.


----------



## Gymschu (Mar 11, 2011)

I've never had much luck with Japan Drier.


----------



## PACman (Oct 24, 2014)

Woodco said:


> Its important to note, that a lot of rustoleum oils require Acetone as a thinner, which also speeds up the solvent drying.


They use acetone mainly because it is a voc complying solvent. It will speed up the drying process but it will also reduce the rust inhibitive properties of the paint. But then again, the faster it rusts the faster you will need to buy more rustoleum.


----------



## PACman (Oct 24, 2014)

Gymschu said:


> I've never had much luck with Japan Drier.


I find that it is actually neither drier NOR japanese.


----------



## Ric (Oct 26, 2011)

CApainter said:


> Japan Drier ( a siccative) actually cures oils through a chemical crosslinking process. A Naptha solvent is going to just evaporate quickly, creating a film surface dryness, but not necessarily a complete coalescing of the paint film. In other words, the Japan Drier's molecular structure acts as a catalyst for oil base paints, accelerating curing through out the coating film, where as the solvent is basically a fast evaporating reducer.


Actually...not really. While Japan Drier is considered a siccative, it's not because of any chemical cross-linking process. It's because, as it relates to oil base coatings, the "driers" (specifically cobalt) draw an extraordinary amount of pure oxygen into the film (cobalts have an affinity for oxygen) - and it is the increase of oxygen that "dries" an oil based paint faster. 

Unfortunately, as Gymschu kind of referred to, Japan Driers really don't accelerate drying all that much - not in any measurable degree at least... And due to the driers that are even allowed to be used anymore (including Cobalt), the result is usually a surface dry and not dry through. So, if all you're looking for is surface dry, stay with VM&P Naptha - it's cheaper, and you can use more of it, but it won't help the oil film "dry through" any faster than will Japan Drier.

And regarding VM&P Naptha...or Acetone....or any other evaporative solvent, please keep in mind that oil base finishes don't "dry" by solvent evaporation...they dry by oxidation. This industry is goofy in the way they use the term "dry" and "cure" synonymously - so, I s'pose it's more accurate to say that oil finishes "dry" by solvent evaporation (which really means nothing), but they "cure" by oxidation (which means everything as far as film-forming and drying hard are concerned).

VM&P Naptha is the varnish makers manipulated formulation of Naptha, which is a faster-dry, lower flash solvent than regular (?) naptha. The flash point of VM&P is usually @ 50 degrees F. - while regular Naptha may be all over the board. (Mineral Spirits flash point is generally 105 degrees. F. - and VM&P Naptha evaporates approximately 14 times faster than Mineral Spirits).

(don't get me started on catalysts....)


----------



## PremierPaintingMa (Nov 30, 2014)

Ric said:


> Actually...not really. While Japan Drier is considered a siccative, it's not because of any chemical cross-linking process. It's because, as it relates to oil base coatings, the "driers" (specifically cobalt) draw an extraordinary amount of pure oxygen into the film (cobalts have an affinity for oxygen) - and it is the increase of oxygen that "dries" an oil based paint faster.
> 
> Unfortunately, as Gymschu kind of referred to, Japan Driers really don't accelerate drying all that much - not in any measurable degree at least... And due to the driers that are even allowed to be used anymore (including Cobalt), the result is usually a surface dry and not dry through. So, if all you're looking for is surface dry, stay with VM&P Naptha - it's cheaper, and you can use more of it, but it won't help the oil film "dry through" any faster than will Japan Drier.
> 
> ...


Man you beat by a mile :wink:
I enjoyed reading this one, thanks.


----------



## CApainter (Jun 29, 2007)

That was a great explanation. And given that oils do cure by oxidation, it is considered a chemical cure coating. Which continues to cure over a long period of time. But still, as a single component coating that relies on solvent vehicle evaporation to immediately help with film formation, I'd be concerned that excess thinner would compromise the full formation and performance of the coating film.


----------



## MikeCalifornia (Aug 26, 2012)

This might be the only forum where "jap drier" is a condoned vernacular. Anywhere else we would be shamed for the shear mention. God I love painting. I'm going to start a thread for midget brushes.


----------



## ThreeSistersPainting (Jan 7, 2017)

I have used naptha and japan drier with Sherwins ProClassic Alkyd. Ended up having better results with the japan drier, even though I felt real weird about dumping brownish liquid into a light gray enamel.


----------



## Ric (Oct 26, 2011)

CApainter said:


> That was a great explanation. And given that oils do cure by oxidation, it is considered a chemical cure coating. Which continues to cure over a long period of time. But still, as a single component coating that relies on solvent vehicle evaporation to immediately help with film formation, I'd be concerned that excess thinner would compromise the full formation and performance of the coating film.


thank you... and true about chemical cure - what I meant regarding cross-linking is that cross-linking is generally molecule A reacts with molecule B to create Molecule C (such as with epoxies and urethanes), oxidative cure is, from lack of a better analogy, like cold temps changing water (liquid) to ice (solid). And you're also right about excess thinner possibly compromising the film forming process of a coating - I probably should've said you can use more VM&P, up to a reasonable level, than you can with Japan Drier... but much really has to do with the type of "solvent" used as to whether the film would actually be compromised - for example: you could literally thin a typical oil based coating 100% with mineral spirits - or more - and a complete film would still form - it wouldn't have near the integrity of a more balanced film, but the film would (theoretically) still contain all the elements of the film as it was designed (just much thinner, with less build, and overall less protection to the substrate) - this is because Mineral Spirits only dilutes the film and doesn't dissolve it (changing the chemical structure). But if you were to thin that same oil base paint with Toluene or MEK - the results would be completely different, as the film is dissolved, rather than diluted, by these harsher solvents.


----------



## jason123 (Jul 2, 2009)

The only time I needed Japan drier is when I have to use one shot.


----------



## PACman (Oct 24, 2014)

the hardware store i last worked at used jap drier in an alkyd paint to do maintenance painting on doors and whatnot all the time. About all it really did was dry the surface well enough that anyone brushing past the paint wouldn't get paint all over them. depending on how thick the paint was it would take a week or two to actually dry hard all the way through the film. I actually think jap driers were originally used in pigmented lacquers.


----------



## Ric (Oct 26, 2011)

PACman said:


> the hardware store i last worked at used jap drier in an alkyd paint to do maintenance painting on doors and whatnot all the time. About all it really did was dry the surface well enough that anyone brushing past the paint wouldn't get paint all over them. depending on how thick the paint was it would take a week or two to actually dry hard all the way through the film. I actually think jap driers were originally used in pigmented lacquers.


Well, sort of... and this will also address MikeCalifornia's comment from yesterday. Japan Varnish/Japan Lacquer - most commonly called simply "Japan", is a very high gloss black (bitumen) varnish/lacquer, with resin derived from the Japan Varnish tree - this is how Japan Drier came to be - an assortment of driers & solvents designed to dry "Japan"...


----------



## Tprice2193 (Oct 3, 2017)

Thanks for the treatise on drying and curing agents. Who said watching paint dry was boring? I call BS to the poster that said there was a lack of expertise on PaintTalk! You guys are Professors of Paint and it definitely inspires me to "up my game".


----------



## Tundra02 (Oct 22, 2014)

:thumbup:Thanks for all the scientific info


----------



## thinkpainting/nick (Dec 25, 2012)

Don’t complicate it been using JP since the 70”s never ever let me down. Just don’t overdue it as it will knock down the sheen if you add to much. We always added some pen along with it when laying off doors.


----------



## Paintergal78 (Jan 30, 2018)

People are into this rustolem deal because it basically states it's all about the rust. I don't have anything against rustolieum but all you need to do to make them happy is just prime the doors then paint. We all know there are prime freaks out there. I am more comfortable priming with about any oil prime in the long run. If they choose rustolieum as their brand than stick to it. I would use any brand of oil primer but that's their chosen brand.


----------



## Tundra02 (Oct 22, 2014)

Paintergal78 said:


> People are into this rustolem deal because it basically states it's all about the rust. I don't have anything against rustolieum but all you need to do to make them happy is just prime the doors then paint. We all know there are prime freaks out there. I am more comfortable priming with about any oil prime in the long run. If they choose rustolieum as their brand than stick to it. I would use any brand of oil primer but that's their chosen brand.


 You don't seem to hip on RustOleum Alkyd why not . I have been using it for 30 years on metal substrates like doors,hatch ways,support columns etc . And is my go to Alkyd paint for such projects.
It's fairly inexpensive and holds up well if you do a good prep .


----------



## NACE (May 16, 2008)

I’ve always found Naptha lowers the sheen on gloss alkyds. Japan Drier doesn’t influence sheen. Aecetone evaporates quickly and doesn’t change sheen. Same with Xylene.


----------



## cocomonkeynuts (Apr 14, 2017)

NACE said:


> I’ve always found Naptha lowers the sheen on gloss alkyds. Japan Drier doesn’t influence sheen. Aecetone evaporates quickly and doesn’t change sheen. Same with Xylene.


Hey Nace I had a guy looking for some old V660 Solvent thinner and I have never been able to find any info on that stuff. The guys at the BM lab told me it was replaced by the M97 Naptha thinner, which in turn replaced by V701 brushing reducer.

I can't find any more info on the M97 or the V660 anywhere. Did you ever run across these products?


----------



## NACE (May 16, 2008)

Yes, they were from the old Ben Moore Indusrial line and are different numbers for Naptha.


----------

