How do I....

[Drawingninjas]

ok, I used to be able to do this sort of thing about two years ago but i just stopped and now i want to start again because i cant remember how to do this sort of thing.

Can anyone help me with what parts i should get to make a cannon like this one http://www.spudfiles.com/forums/m25-sni ... 15093.html

and where would i be able to buy the parts from because the shops here in Liverpool UK don't have much choice with these parts.

Thanks

[trollhameran]

B&Q will have everything you need to make a gun like that, you may have to make a piston valve though because I think that one uses a home made QEV and it would probably be easier to make a piston.

[jackssmirkingrevenge]

These guys do mail order, so I hear