I’m building my first model and selected the Tamiya Merkava.
But when I started to apply the oil paints for weathering, it looks like the original acrylic painting is being attacked by the white spirits that I’m using. original color is turning whiteish… almost as a stain.
I’m using Testor’s oil paint with this White Spirit from the picture.
Hmm, I haven’t seen that before. There are only two things you do differently from what I do: 1) the brand of mineral spirits; 2) the brand of oil-based paint.
I’ve used Winsor and Newton spirits with artists oil paint over Tamiya acrylic before without problems. Maybe there is something in the Testor’s enamels that is causing a strange reaction. Personally, I’ve never tried weathering with enamel paints, I’ve always used artists oils (the kind that comes in a tube).
As for thinners, I have switched from mineral spirits to odorless mineral spirits, which are a bit weaker than the smelly kind. That may be a factor.
It could also be that you are using too much thinner to streak your oil paint. Try not to flood the model with thinner. I used a brush that is just ever-so-slightly damp with the thinner. I dip the brush in the thinner, then dab the brush onto a paper towel to remove most of the thinner. Then I use that barely damp brush to streak the oil paint.