
maximum TIME i can spend is 30h
i know this is hard question but i just need to get something to do
i cant make spudguns

here is some of my own ideas that i have thinked to make:pulsejet engine,vacuum forming machine for plastic, piston valve for high pressure


.............................................................
EDIT:

I think i`m going to make piston valve with 2" out let ,valve body would be made out of steel pipe ,piston would be aluminium or nylon or something that i can get from finland

my teacher dont even know what piston valve is, so i think he would be very impressed if i make one

also piston valve would be good because i have made many of them so i know I could make it work very well
