It was just a case of getting the pressure right. But I also think somethings not right with the compressor. The pressure keeps dropping, and it has to be sprayed for a few seconds before it reaches a decent pressure...but then the pressure just keep rising, so something isn't right and I've got to keep guessing at which point to do subtle fades without putting to much air pressure through and spoiling the shells.
Not sure if it's because it kept in a cold out-house or not.
