Nicholas Lee wrote:sweet jeebus.
whats the pressure source? canned CO2? shop air?
For the big one, shop air. I have a 5 gallon portable air tank/compressor, so I can fill it for 2-3 shots without energy.
The little one, a bike pump will fill pretty easily.
I've seen pressure recommendation for PVC upwards of 100 PSI, but I like having my abdomen shrapnel free. So I am thinking 60-70 PSI max.
The last potato gun I made, I wrapped in hockey tape 4-5 layers deep to keep any catastrophic failures from shooting out sharp pieces. I think the big one will get that treatment as well. even though its already quite heavy.