SEM TRIM BLACK crazing

I'm guessing the brass still had minute amounts of detergent on it.  Try cleaning with acetone (wearing gloves) and see how it goes...

You should use the same brands of paint and primer, as incompatibilities can occur.  Also, since no plastic is involved, I suggest baking the parts for an hour or so at 150 degrees...

Mitch

???  Who knows what is in a rattle-can, or how long it has been setting on a shelf.  Cold weather shipping is another variable.  I have had good and poor results. 

Gray, what primer did you use?……if your material goes on too heavy, and doesn’t fully gas out, crazing can happen, …..this is true of the primer, and the color. SEM or anybody’s paint can craze when applied too heavy,…..I only use a primer on spots I’ve had to do putty work on. …..even on brass, I’ll shoot the SEM directly onto a properly scuffed surface, ……remember, the SEM is a urethane product, ……so if you have crazing on metal panels, only one of two things…..either the underlying primer wasn’t fully cured, and the wet color attacked it, or the second coat of color was too wet, and it attacked itself….

Pat

The primer was Rust Oleum Proffesional bought at an automotive paint store, same place the SEM was bought.  The primer was two weeks dry.  I put money on the SEM attacking itself as it started at the rain gutter (thicker) and spread.

Will the Urethane harm plastic?  AS trim paint, I wouldn't think so.

Is no primer a standard now?  Of course a car repaint in most cases isn't taken to bare metal unless in a maybe frame off restoration.

I still am trying to apply 70 year old paint principles my Dad learned ant his Dad's garage in the 1950s.

Gray

For model work, unless you’re trying to hide, or blend, primer IMO, really isn’t necessary, ……you definitely had a chemical reaction between the rustoleum product, and the SEM, …..if the SEM is attacking itself, then it’s going on too wet & heavy,….don’t try and do the hide on the first coat ….sounds like your flash times are good, but it sounds like you’re going on way too wet,…..

Pat