Have a wooden base sprayed it with outdoor spray paint. The wood was untreated; I then used a brush and applied water and white glue to my “wall covering” putty, sprinkled on fine cat litter (crushed). Tapped off excess. My problem when I airbrushed little flakes came of exposing the putty I used as groundwork, and when it dried the ground stated cracking. So what do I do to avoid the AB blowing chunks off my ground work? BTW I gave the cat litter on the ground about 10 minutes to dry before I started ABing, could that be the problem?

I think you should have waited longer than 10 minutes. When I make a base I usually let it sit overnight (or however long it takes to dry) before I start painting it. White glue itself takes longer than 10 minutes to fully set. Patience, my friend, is the name of the game. As far as the craking goes, perhaps you your base mixture didn't have anough water. It is hard to say.

Did you use non-shrinking type of mixture ?

Hey,
I agree with Marty - wait over night for the base to dry. I would go heavy on the glue less on the water 70/30 G/W. I would also drop the PSI on the AB down a bit too. I would also spray at as close to 90 degress from the base (if the affect your looking for allows this - shadows may not let you do it).
The cracking is based on the spackle you used. When I purchase this stuff I look for the vynal/synthetic kind - this stuff resists cracking. This is what ToonArmy is referencing.
You may want to consider two coats of spackel if you want to keep using the stuff you have.
Use two thin layers and let each dry completely.

I had this problem and realized i did not wait long enough......Overnight is a good rule of thumb

God father. When i use filler or spackle I mix up some cheap acrylic paint to get a rough ground colour then mix it in with the filler saves a lot of brush work and helps avoid white spots.

Hi Easy. That's an interesting tip ! I'll remember next time !
Jan

In the mixture, dose not matter which, I always use a generous amount of white glue and water. Once everything has dried properly I give on top an extra coat of white glued diluted at 50% with water. This usually gives extra adhesion to all the bits and pieces...
Ciao
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