Don't Mix Krylon and Rust-oleum

[gbcaboose]

 For a while I've been using Krylon Oxide primer in the rattle can when painting solid colored boxcars. After applying decals I coat the cars with Krylon Flat or Satin clear acrylic. I've had nothing but success as the primer dries really thin.

Well..... The other day Wally World had all their Krylon and Rustoleum rattle cans for 2.00 (I think they were re-setting the paint aisle). I picked up a can of the Rustoleum Primer to give it a try as it's more brown than Krylon's oxide primer. All was well until I hit it with the clear coat. In second's it all went south. Apparently the Rustoleum doesn't like a nice clear acrylic finish over it. It seems like I've never had any trouble shooting acrylics over enamels or solvents when airbrushing. I'm not sure what the rustoleum is but if I ever use it again I be sure to clear coat it with another rustoleum product.

1st pic: the normal Krylon results.

Other pics: Disaster.

Mike

[StarCruiser]

YIKES!!!

Bad reaction indeed...

[peteski]

That is a bad reaction!  Thanks for the warning.   Mixing paint lines or paint brands ls always an iffy proposition.
It is always a good idea to test new paint combinations.  I call that a "spoon test". Using a cheap polystyrene disposable spoon as a test subject, I spray it with the new paint combinations I am planning on using on a model.  That way, if there is a bad reaction, I will not have to redo the model.

Make sure to use the cheap polystyrene spoons (recycling symbol is #6), not the flexible polypropylene ones.

[mmagliaro]

I found a Q&A on Krylon's site about the Crystal Clear where they say it is an "acrylic lacquer".

The only time I had that type of reaction that you show is when trying to spray clear lacquer (dullcote) over enamel.  The finish got destroyed in exactly the same way.    Rustoleums are enamels, so it looks like that was your problem.

You did say you've sprayed acrylics over enamels with no problem, but were they water-based acrylics?.  Krylon's "acrylic lacquer" is definitely not water based.

After my own personal disaster, I used a semi-gloss urethane spray as my top coat.  The enamel didn't have any problems with that.

[gbcaboose]

You did say you've sprayed acrylics over enamels with no problem, but were they water-based acrylics?.  Krylon's "acrylic lacquer" is definitely not water based.

No they weren't. I usually use the Model Master Acryl Flat and it is water based.

If there's a bright side, it only took a few minutes to strip the paint in a jar of  Alcohol.  And the decals were just a hodge-podge of data and individual letters and numbers, I have plenty more.

Mike

[tom mann]

There’s probably a prototype for that, and you just discovered a technique!

[Ed Kapuscinski]

There’s probably a prototype for that, and you just discovered a technique!

Actually... yeah, it would be nice if this were a way to controllably recreate the beer canning effect that Fine N Scale got right on their boxcars.

But controllably is the operative word there.

[johnb]

There’s probably a prototype for that, and you just discovered a technique!

Looks like warped metal after a hot fire..

[nkalanaga]

I spray DullCote over enamals all the time without problems.  However, enamals over a lacquer are another matter.  That often doesn't work well at all.

If spraying a water-based acrylic doesn't work, what about water-based acrylic weathering?

The only advice I can give on Rust-oleum is that I don't use it.  Like you, I tried their red primer once.  Krylon's "Ruddy Brown Primer" is the standard "boxcar red" for my narrow gauge.  It works well on styrene, as long as it can't sit wet long enough to damage the surface.  The one time I tried Rust-oleum it ate holes in the Evergreen scribed siding.

[mmagliaro]

I suspect it has a lot to do with the enamel formulation.  In my failure case, it was enamel mixed at a Miller Paint store because I wanted a custom Loewy green to repaint an NP passenger car.   I don't think that is the same formula as, say, the Testors enamels in the little glass bottles.  When I showed the guys in the store what happened they knew instantly - "No!  Don't use lacquers over enamel", they told me.  And they suggested something with a urethane base instead.

[peteski]

I suspect it has a lot to do with the enamel formulation.  In my failure case, it was enamel mixed at a Miller Paint store because I wanted a custom Loewy green to repaint an NP passenger car.   I don't think that is the same formula as, say, the Testors enamels in the little glass bottles.  When I showed the guys in the store what happened they knew instantly - "No!  Don't use lacquers over enamel", they told me.  And they suggested something with a urethane base instead.

There are multiple factors when it comes to paint compatibility (not just that token enamel vs. lacquer thing).  The "hotness" of the solvent used, and the chemical composition of the other paint's binder (the resin which holds the pigment, and which also adheres to the painted surface) greatly affect the compatibility.

[CRL]

Don’t use Rustoleum on anything other than metal. If it don’t rust, don’t paint it with that stuff.

[davefoxx]

Don’t use Rustoleum on anything other than metal. If it don’t rust, don’t paint it with that stuff.

Say what you want, but Rustoleum Light Gray Primer is my go-to aged asphalt color.  The darker gray primer is my "asphalt patch" color.

[nkalanaga]

CRL:  I tend to agree.

DaveFoxx:  For roads, even styrene roads, an aggressive paint may not be a bad thing.  I used a can of "cold galvanizing compound" for most of my paved roads.  It did craze the surface of the styrene sheet a little, but the cracks looked quite natural after weathering, and it definitely won't scrape off.  It wasn't shiny at all, a nice flat medium gray.  I bought a second can, and it was a shiny silver color, and the color rubs off the surface very easily, although the base stays stuck to the plastic.  Got lucky on the first can - apparently it was defective!

[peteski]

CRL:  I tend to agree.

DaveFoxx:  For roads, even styrene roads, an aggressive paint may not be a bad thing.  I used a can of "cold galvanizing compound" for most of my paved roads.  It did craze the surface of the styrene sheet a little, but the cracks looked quite natural after weathering, and it definitely won't scrape off.  It wasn't shiny at all, a nice flat medium gray.  I bought a second can, and it was a shiny silver color, and the color rubs off the surface very easily, although the base stays stuck to the plastic.  Got lucky on the first can - apparently it was defective!

I was just going to say . . . cold galvanizing spray paint is mostly powdered Zinc.  The can of paint is noticeably heavier than the other spray cans of the same size (due to all the powdered metal in there). It also takes a long time to agitate all the metal powder and mix properly - needs a lot of shaking!  Then the painted surface will have a dull silver metallic finish (again, since it is a metallic Zinc).  I have no idea why the first can wasn't like that.