SpudFiles

ok guys cool,... guess its back to the drawing board...
PS Im not living in america soo that 30 saving is actually $60 here soo yeh thats why i went wid the blowgun valve at first.... but if it means super crappy performance ill adjust. Cus I did do a firing test earlier n i was a bit disappointed

don't forget to check ebay for sprinkler valves, they can be cheaper there if you can find them.

good luck with it all

You could always just opt out for a ball valve. I'm sure they would be cheaper than your sprinkler, if you don't' find one on ebay. Of course, you may want to add a spring to give better opening times to it.

Another option would be a burst disc valve. The wiki has a pretty neat section on triggering a burst disc, in which you could use your blowgun valve.

In short, don't think you are limited to purchasing a sprinkler valve. It is a choice (and a fine one for your needs) but it is not the only choice.

Unless you don't mind a rate of fire less than 4 rph (rounds per hour), and building one of the most difficult valves to seal, don't use a triggered burst disk. They sound great, and have loads of flow and opening time, but they aren't practical at all.

Just build a piston valve. With lots of epoxy, they can be built to a decent size very cheaply, less than a sprinkler valve.