i got some vellum printed on today and was wondering how much longer i should burn the screens for. i usually use regular acetate at 12 min. with ulano tz dont know the watts but that how long i do it for now.
Such a tough question to give an exact answer. If it's plain drafting vellum, and your burn time is usually 12 minutes, maybe add a minute or two to that time. Not sure. I think anyone is going to tell you: trial and error.
You should do a few test screens if you can, anyway, because I'm sure you'll get something on vellum again in the future.