Paint thinning for Spray

I'm using a Rustoleum-like metal primer called "Rust Coat" which I think may even be made by Rustoleum. Anyway, it is dynamite primer for aluminum as well and I'm wondering if Acetone is a good reducing option for spray.

I had been thinning this primer and paint with turpentine.

I mixed a little of this white primer with acetone as a test, and nothing unusual happened, but I'm still uncertain.

Thanks,
Terry

We don't know how the paint was formulated so I would play it safe and follow the directions that indicate to thin with Naphtha.

It was this guy and others in video on the right using Acetone for reducing, that got me wondering.
I have a can of Acetone but no Naptha. Hadn't thought of Naptha until you mentioned it.
Rusto/Acetone

I guess I should phone the techies who make this primer.
If I understand you correctly, you are saying to read up on "thinning with Naptha" . . . because there is no mention of naptha on the can.

Thanks,
T

I see . . .
It seems that Naptha is more akin to this paint because Naptha is a petroleum solvent and so more inclined to be stable and compatible with it. (?)

got that from this:
Turpentine and mineral spirits are good brush cleaners, and turpentine can remove paint that has hardened slightly. Mineral spirits will dissolve only paint that is still fresh. [b:bc1376c6a4]Naphtha is a petroleum solvent similar to mineral spirits but with a greater volatility[/b:bc1376c6a4]; it is used chiefly as a paint thinner or a cleaning agent. Naphtha is a more powerful solvent than mineral spirits, so less is needed to thin the same amount of paint. But it also makes paint dry faster and may make it hard to blend strokes or brush out drips.

Like Dollar Bill said, read the label...most enamel based tractor paints use mineral spirits or enamel reducer..

If the primer is lacquer based, you`ll need lacquer thinner, or possibly acetone; both of which are too "hot" for enamel based paints.

TomT

(quoted from post at 18:14:02 06/08/18)
Like Dollar Bill said, read the label...most enamel based tractor paints use mineral spirits or enamel reducer..

If the primer is lacquer based, you`ll need lacquer thinner, or possibly acetone; both of which are too "hot" for enamel based paints.

TomT

Click to expand...

Tom,

I do follow the instructions to the letter when spraying Valspar tractor paints, using the correct reducer and hardener for that urethane.

but I'm also going to also be using the same Valspar type paint to paint my '51 Van.

So here's where I'm stuck.
I know the metal primer I'm using on this aluminum body will be OK under the Valspar, but I thought that one had to thin regular paint for spraying with something more volatile; i.e., that would evaporate more quickly, like Acetone or Naptha.

So maybe I don't have to reduce with anything other than what the can of primer calls for; i.e., mineral spirits/paint thinner/turpentine. (?) Is that what you're saying?

Remember I'm talking spraying not brushing and that Dollar Bill did suggest Naptha, which I now have on hand..

Thanks,
Terry

terry,

My reply was based on my own recent experience using automotive acrylic enamel medium dry reducer with a house brand tractor enamel...

I got less than favorable results, and had to re-sand and repaint a few weeks after painting the first time...I had hoped I would get a high gloss finish, but It was dull and flat. I ended up using mineral spirits the next time, and got a good, high gloss finish.

many years ago on my first DIY paint {primer} job, I picked up a quart of red oxide primer from the local body shop. I was a teenager then, and didn`t know what questions to ask; and they didn`t tell me ...so when I mixed paint thinner in the lacquer primer, it was like oil in water...they just wouldn't mix.

my original reply was only meant to help, and I didn`t mean it to sound condescending, or that I am know it all.

Respectfully, TomT

Tom,

I've had paint mishaps like that before.

but here, I'm not messing with any Valspar tractor colors or paint
only this metal primer I have that is incredible on my old van even after the paint on top was the first to wear away in 20 years,

So ALL I want to do, is reduce this Rust Coat primer that I AM going to use on my aluminum van again . . . reduce it for my spray gun.

So far we have 3 primer thinning possibilities:
• Naptha
• Acetone
Or what is written on the primer can (paint thinner/turpentine family of solvents).

I have been thinning it with turpentine for all the brush work I did with it on my restored Chev gas tank.

I know . . . when in doubt go by the manufacturer's thinner recommendations but I like the faster flashing idea of spraying it
which leads me back to naptha . . . a petroleum distillate.

That Naptha tip was worth a Dollar Bill

I found a good explanation of it all here:
Thinning For Spraying

EXCERPT
Choosing a Solvent to Thin Alkyds

Alkyd paints are a solvent based finish. They consist of a polyester resin and are crosslinked by drying vegetable oils and fatty acids. The traditional solvent for oil based paint is mineral spirits. This slow evaportorating solvent keeps the paint wet long enough to assist in leveling. Mineral spirits are unsuitable for spraying alkyds unless it is very hot. This is because it dries too slow and is suseptable to runs. Therefore a faster evaporating solvent is desired. The common choices are VM&P Naptha, Xylene, and Acetone.

Xylene, pictured above is an aromatic hydrocarbon solvent of medium strength. It evaporates slower than acetone or naphtha but faster than mineral spirits. The higher solvent strength allows the xylene thinned alkyd to bond better with primers. It will produce somewhat glossy finishes but not that shiny and it still evaporates slowly at temperatures below 80 Fahrenheit.

Acetone is the fastest most powerfull solvent available. In fact, it evaporates so fast that if you spread it on a smooth and warm surface it will dry while wiping it. [b:d681429098]Using this alone to spray paint would be bad as it would evaporate too quickly.[/b:d681429098] Most spray paints in cans use acetone as the principle solvent but usually add in xylene or other petroleum distillates to keep the paint from flashing the solvent too quickly.

VM&P naphtha is a petroleum distillate much like mineral spirits but it evaporates much faster and leaves no oily residue. It does not flash off as fast as acetone though. [b:d681429098]It is perfect for spraying in that it limits sags and runs.[/b:d681429098] It also allows the alkyd paint to level out a bit as well producing a finish with a “wet” look.

Thanks,
terry