Certainly not to beat a dead horse or start a flame war, but I pulled out my trusty 350 this morning to see for myself what the deal is with the color cup. Reason being is that Badger has been selling that brush for forever and three Sundays and that topic has not come up. Badger's instruction booklets in general are very informative as to airbrush use. The Vega, Omni, and Renegade brushes use leaflets that cover general use because thay are marketed towards the experienced airbrush user. As far as the 350 goes, my humble conclusion is that, although most of us do twist, it is not required. A simple, but firm, push will seat it very well and requires a steady pull to take it out. The original poster may have had some other issues with his brush, but my color cup stayed put. I experimented with both Badger's and Paasche's cup.
E