thanks for the replies. I will try the retarder in the black acrylic. I actually used it in the Gunze Sangyo once, It blushed and never cured, but I have used it in testors. When i say it "immediately" cracked like dry mud, i mean like on the first pass of the airbrush, and got worse with wet coats! letting it cure so i can sand it and try again. will let you know how it works.