In the past I have always thinned my Tamiya acrylics with their acrylic thinner X-22A.I never protected the base coat and it stood up well to enamel washes and filters.

This time I thinned the Tamiya Acrylics with their Lacquer Thinner as some have suggested,it came out very nice.My question is,will this also stand up to enamel washes and filters,or do I need to protct the basecoat ?

Thanks for any answers

once the acrylic coat has hardened it will withstand the enamel wash. But for security just do a compatibility test on some scrap plastic, it never hurts.

It doesn't matter if you use acrylic or lacquer thinner since its purpose is to dilute so the resulting paint to thinner ratio is good enough to be sprayed through the air-brush at proper pressure and with satisfying coverage. Once the paint layer is fully dry, there is no thinner left due to its evaporation. "Fully dry" is the key to success here. I myself used enamel washes and/or filters mixed from Humbrol and Revell paints over an acrylic base coat without any separation (Future)layer between the two. They never damage the underlying paint. In fact, paint soaks a certain amount of the mixture making the effect less radical/dramatic and adding to the general slightly faded appearance of painted surfaces. Just my two cents based on personal experience...