]There have been a number of T-shirt cannon threads in recent years; you can find plenty with some searches, including ideas for rolling t-shirts and working through various problems. Here are a few key items:
- Safety first! Do not use PVC, or other hoses/tubes/pipes that break in a brittle fashion; make sure that all components are rated for the appropriate PSI of air (not just water). Air at a given pressure has a lot more stored energy than water and while air may or may not be more likely to cause a rupture than water would, the consequences would be much worse.
- Large airflow at relatively low pressure with a brief open interval for the solenoid is the favorite way to go. We use about 50 psi through a 3/4" brass solenoid valve, and 1+" pipes most of the way, open for 40-50ms. If I were building now, I'd get a 1" brass valve so we could take the pressure down a bit more. (We have a 3" ID barrel so its similar to yours).
- It takes a lot of energy to launch a t-shirt. Don't plan to power the compressor from an FRC battery; either use air compressed off-robot (our method) or get a larger (marine deep-cycle) battery.