my husband suprised me with an airbrush machine yesterday i've never used one so my question is can i use thinned gel color or do i need to by strictly for airbrush? Also this machine came from Hobby Lobby, do you think it will be okay for cakes

I would use the colors made specifically for airbrushes. As for the source of the machine, as long as it has only ever been used for food, or is brand spanking new and never used, I think you are ok.

definately do not use thinned down gel. in a store bakery we had the good kopykae brand airbrushes and they are rathr finicky. and can get clogged up very easily even when using the correct colorings.

Use airbrush color only. And try to buy an airbrush cleaner solution also, using it regularly helps prevent clogs.