Last night I sprayed my 1/4 scale Taylorcraft and the finish blushed on the seconf coat. Anyone know what can be used as a compatable retarder with this system?

Blushing is usually caused by high humidity. If you wait until a dry day and spray a light coat of thinner it will generally make the blush disappear. I use Certified Coatings or Randolph brand dope and both companies make a retarder for butyrate and nitrate dope. The various brands seem to be interchangable, but If you use a product not made for dope, there is the risk that it won't dry at all.

It's correct that blushing is usually caused by high humidity. If you live in Houston, it is a fairly common problem. You can buy retarder from Sig that is compatible with their dope. I have also used Acrylic lacquer retarder, obtained at automotive paint stores, on occasion an it works OK.
It's also true that you can get rid of the blush by spraying a coat of thinner on the painted finish on a dry day.

Thanks for the replies guys, I wasn't sure if there was a retarder for dope or not. It was a cool evening but the humidity did not seem to bad at all and I have an effective water trap on the comperssor so I was suprised to see the blushing. If it was an automotive finish I could use a myraid of things but was unclear on the dope side. Again thanks for the info.