Can Rustoleum Be Thinned?

[oldcarfan]

Because I'm a glutton for punishment and also because it's the only thing for sale in my area, I'm thinking about try to decant some Rustoleum and spray it through an airbrush. Add to this I came across a stash of 30 cans of all different colors. The question I guess, is does anyone know what the chemistry is on Rustoleum paint is? I know it takes forever to harden out, so my guess is it's old school enamel, but does anyone know for sure? Can I use maybe lacquer thinner or something?

[Ace-Garageguy]

You're going to get 14 answers starting with "I heard..." or "I think...", all of which will be useless.

Decant some. Try lacquer thinner (which works great in old Testors bottle enamel). Try enamel reducer from a real-car-paint outlet.

If those don't work, try other stuff (except water).

Then you'll know for sure. 

 

[Classicgas]

Most spray paint is thin enough out of the can to spray through a air brush.

[StevenGuthmiller]

Rustoleum enamel spray cans appear to be the same type of paint as the little square bottles of Testors enamel.

I've been buying these cans of Rustoleum enamel and successfully thinning them with lacquer thinner.

It still takes a while to dry, but it speeds things up a little.

 

 

 

 

 

Steve

[Oldriginal86]

I have a can of flat black just like the picture Steve posted above that I thinned with “odorless” mineral spirits for airbrushing. I emptied the airbrush back into the can when finished. Next time I opened the can the paint had somewhat solidified. I have since used it thinning with lacquer thinner. It does clog the tip once in a while. I don’t think the “oil” in the oil base is mineral spirits even though the can says to thin with mineral spirits. Maybe it could be the odorless type I’m using.

[bobthehobbyguy]

You never want to return thinned paint back to the unthinned paint. It tends to ruin the unthinned paint.

[Oldriginal86]

If all is compatible why would this practice ruin the original paint other than changing its viscosity?

[Classicgas]

It changes the chemical properties of the paint. I paint for a living, never a good idea to put thinned paint in with fresh.

[peteski]

Yes the solvent in paints (what makes them liquid) is a mixture of several chemicals.  The additional thinner you add will likely have slightly different composition than the solvent already in the paint. Like Lee stated, that will change the chemical balance of the liquid paint which can cause it to start hardening prematurely.  It pretty much happens just to enamel paints (since those have more complex drying/hardening process than lacquers), and not all enamels will be affected. The rule is not to put thinned enamel paint back to the unthinned container.  Well, lets include lacquers to be on the safe side.

[Bills72sj]

If I decant or thin paint. I put it in its own container. Sometimes it will store well. Sometimes not. The Rustoleum cans that Steve pictured above prompted me to buy some. The semi-gloss black mixed so-so with Mr Leveling Thinner. I did spray ok but the black pigment does try to settle out at the bottom. Both the Gloss black and the Semi-gloss black seem to like hardware store lacquer thinner. I sprayed 50/50 but I think it could be thinned more as well.

[StevenGuthmiller]

12 hours ago, peteski said:

Yes the solvent in paints (what makes them liquid) is a mixture of several chemicals.  The additional thinner you add will likely have slightly different composition than the solvent already in the paint. Like Lee stated, that will change the chemical balance of the liquid paint which can cause it to start hardening prematurely.  It pretty much happens just to enamel paints (since those have more complex drying/hardening process than lacquers), and not all enamels will be affected. The rule is not to put thinned enamel paint back to the unthinned container.  Well, lets include lacquers to be on the safe side.

 

9 hours ago, Bills72sj said:

If I decant or thin paint. I put it in its own container. Sometimes it will store well. Sometimes not. The Rustoleum cans that Steve pictured above prompted me to buy some. The semi-gloss black mixed so-so with Mr Leveling Thinner. I did spray ok but the black pigment does try to settle out at the bottom. Both the Gloss black and the Semi-gloss black seem to like hardware store lacquer thinner. I sprayed 50/50 but I think it could be thinned more as well.

A little insight on the paints that I pictured in my post.

The flat black and satin black seem to spray and hold up well once thinned with lacquer thinner.

The gloss black sprays well, but longevity after the fact is not great.

The paint turns to jelly within a few days.

 

So if you decide to use the paints pictured, mix only what you will be able to use up in a short period if you're using the gloss black.

I have no evidence of this, but I assume that other gloss colors in the same line will probably act in the same fashion.

 

Fortunately, there's so much paint in one of these little cans, that I don't mind losing a little to drying up.

 

 

Steve

[Oldriginal86]

Won’t do that again. I though since it was such a small amount that it wouldn’t hurt. Then again I should have just dumped it. Thanks for the explanation.