Paint woes

[robhart]

I primed this body last weekend with Tamiya white surface primer thinned about 50/50 with Klean Strip lacquer thinner. The paint dried very rough and gritty with poor coverage. I usually use Alclad primer, but I didn't have any Alclad white primer, the kit is molded in red plastic, the final finish will be two tone red and white, so I wanted to use a white primer, and I had the Tamiya primer on hand. I sprayed at 10 psi. The weather at the time was a 'Santa Ana' condition where the ambient temperature was about 85 degrees F and the relative humidity was 10-20%. I'm not new to airbrushing and had used the Tamiya primer on smaller surfaces/parts in the past without any issues. This was the first time I used the Klean Strip lacquer thinner and, judging from the rather intense odor, may be hotter than the generic lacquer thinner I've used in the past.
I'm thinking that perhaps the combination of the hotter thinner, the very low humidity/high temperature, and maybe my holding the airbrush too far from the what I was spraying combined to produce the bad paint job, but I'm open to suggestions/advice. I attempted to sand and polish out the rough primer, but in doing so I noticed some low spots and mold flaws on the body that I hadn't seen before and I ended up taking the primer off down to the plastic in spots. The body is now soaking in oven cleaner and I ordered a bottle of Alclad white primer.









By contrast here is the tub that I primed with Alclad

[Chris K. Hale]

OK all Primers are essentially a base almost like a filler and a propellant, it would appear the Tamiya base is plastic/polymer based, Klean Strip Lacquer thinner is a Hot or flash dry solvent that melts plastic/ polymers.. and is not recommended for Tamiya Primer with obvious result. Alclad and Model Master Lacquer thinners are slow and cool thinners and would work fine. I use the Klean Stip to clean my airbrush, remove paint and clean tools but never for airbrush painting or thinning model paints..Most Paint Manufacturers make thinners for their specific product and it is best to go product specific.. Source of info, House of Kolor/Coast Airbrush, Testors tech & Klean Strip when I sold it..I hope I explained it alright..... live and learn I guess.. Chris

[robhart]

Thanks for the info. I'll discontinue using the Klean Strip to thin model paints. I suspected it may have been the culprit.

[Art]

Hi Rob,

The Kleenstrip isn't all bad. I've used it for the past four years or so to thin all my Testors enamels at a 2-1 ratio with great success, including the Lola T-332 I'm working on now. But that's over Tamiya or Duplicolor primer and not bare plastic. It could very well be too hot for that.

-Art

[robhart]

Art,

Thanks for the advice. I'm going to do some experimenting with various lacquer thinner and paint combinations to see if their are commonalities. In fact, one of the reasons I started this model was to gain more experience building in a larger scale with the attendant painting of larger areas.

Rob