Help with a wash

I'm no expert, but for some reason I've had some pretty good results with engines...and it's sort of the reverse of what you did. This is better for older motors, but may work in your case. Washes have been problematic for me as well, and it's tough to get the final look right.

 Basically, I airbrush the whole motor assembly in flat black, then apply a *heavy* drybrushing of Tamiya metallic gray. Silver or aluminum would probably work as well, but the end result is that the flat black stays in the recesses and the sheen duplicates the worked-in oil/grease look.

GRANT ED wrote:

The engine is painted in Tamiya acrylic so I thought I would do my wash with enamel. I mixed up some wash using Humbrol paint and Mr colour thinner. When I applied this to the engine the ali paint bubbled up and started to come off. I thought the thinner might be too strong so I tried again with some model master thinner and that had the same result. I have read that I'm supposed to do an enamel wash over acrylic paint so what am I doing wrong here?

The Mr Color thinner is definitely too strong. It's a lacquer thinner which, although weak compared to generic lacquer thinners, will cut through any sort of model paint. Your saving grace is that it's been formulated to be styrene friendly and won't melt your model (unlike the generic hardware store type lacquer thinners).

I'm not sure why you had the same problem with the Model Master thinners though. 

Hi Grant, 

Metho is 90%+ Ethyl alcohol and will strip Tamiya acrylics off faster than you can blink. You can clean your brushes and airbrush with it and it will work as an alternate thinner if the "real" stuff is unavailable.

I use oil based washes over Tamiya acrylics using artists oils and "AS" (Art Spectrum) brand odourless solvent. You should be able to find this (or an equivalent) at your local art supplies store. It's a little pricey - mine cost about $10.00(AUD) for a 500ml bottle (will most likely be more than that now), but that quantity should last for years. It has no ill effects on cured Tamiya acrylics but it will lift Gunze acrylics. I haven't tried it over enamels, but seeing that it won't mix with ModelMaster enamels, I suspect it won't affect those either.