I started creating Science T-shirt designs when I was a grad student in 1982 and I'm still enjoying making them. Each shirt is hand screen printed on order, so please be patient. It takes about ten days usually. I mail them Priority mail USPS. I use Fruit of the loom Heavy Weight shirts for Adult.
I sell frequently in the Bay Area, either in San Francisco, or Telegraph Ave. in Berkeley. To find out where I'm selling, follow me on Twitter.