Have you ever had a process or technique that you've used many times without ill effect suddenly and without warning go to heck in a handbasket? I've repeatedly used turpentine and artists' oils as a wash over various barnds of acrylic paints without encountering problems; I've never sealed the acylic with laquer or Future, and it's never been a problem before.

Well, it was a problem this weekend. I had just painted Tamiya's Marder III with Testor's Model Master Acrylics and was applying a turpentine/Windson & Newton oil wash when the paint began to melt. Worse, I couldn't get it to dry, and it began to soften the PLASTIC. 24 hours later, the plastic/paint sludge that was the new surface of the lower hull of the model was still sticky, and was starting to attract lint/hair/dog fur from the air. Scrubbing with water- or clean turnpentine-soaked Q-tips or rags did nothing to alleviate the problem. Finally, I just got out the airbrush and painted over it. That seems to have solved the problem, though who knows what kind of cancerous decomposition is taking place beneath the paint.

Luckily, I had only applied the wash to the area of the hull that is behind the wheels, so the model isn't ruined, per se, but it was a huge mess. Worse, I'm quite scared to apply a similar mixture as a wash in the future. Guess I'll have to start sealing the acrylics with Future or some other protective layer. Anybody else ever had this happen to them?

Hi Part Timer!

Oh yes!! I've had a few disasters! The first time I tried oil washes over an acrylic varnish it worked like a dream... the next time (and I've no idea what I did different) the turps "ate" the acrylic varnish and everything beneath it!

To be honest, I've chickened out and mostly use an acrylic wash for panel lines - it's non-agessive, dries quicker and can be cleaned off easier if it goes wrong. Can' tbe bad!

I think oils probably give greater subtlety and may be better for shading larger areas, but if they go wrong...

All the best

Rowan

I always use mineral spirits for washes instead of turpentine. I was thinking maybe turpentine in too "hot" for washing, but since you've used that combo before it shouldn't be the cause. Have you switched brands of turpentine this time? Or maybe applied the wash much sooner after the acrylics this time? I think its a good idea to let things cure for at least a couple days before doing any washes.....whether its really needed or not I figure it can't hurt!

I used the same oils with turpenoid on MM Acryl with no problem at all last week? Weird, Did you clear coat it?

I´ve learned that always before applying the Tupertine - Oil Wash over the acrylic paint I have let it dry very well (I leave it 24 hs) and then seal it with Future or a Clear Varnish Coat and let it cure for at least 24 hours again. Also I use always the same brand of Tupertine, one that I fund that´s not very agresive. I beive that is very important that the Acrylic Paint and the Clear Coat must be very well cured before applying the oil wash. I used this thec. last weekend in my Ju 87 and worked fine. I used Vallejo Model Air acrylics and Future.
This doesn´t means that this is the perfect method, in this matter no one has the truth.

I think Grifter and csch have hit on the explanation. I haven't had much time for modeling recently, so when I got into it this weekend, I was determined to get through as much as possible; there was probably less than 3 hours between the final coat of paint and the wash. As is so often the case in modeling, it appears that impatience was impermissible, and my haste only made waste.

I think the model has been rescued, but it was a frightening and frustrating experience. I'll certainly let things sit for a few days before washing from now on.

I'm with Grifter and csch on this. Another option (but you have to wait at least 24 hours for drying) it's a coat of transparent flat clear from Hobby Color if you prefer a matt to a gloss base for your wash/filter. Since i use that for matt and Future for gloss I've never had a problem with any kind of solvant I use to thin my oil wash (zippo lighter fuel, white spirit, turpentine, etc.)
Ciao