Thanks guys for the feedback! Think I will take the risk and use 350psi. Has anyone ever experienced a QEV failing, when the diaphragm blows out?

Does anybody out there think it is safe using 350psi on a 150psi rated sliding valve, or on a 150psi rated QEV? Increasing the pressure will no doubt decrease the lifespan. I heard the diaphragm will fail first on the qev. What about the sliding valve? Will there be any leakages on either of these, ...

fenrir wrote:It's ok to use 350 psi. The worst thing that could happen would be the diaphram getting blown out.

Do you think it will be safe to use a sliding valve to pressures of 350psi?

Ahh it's working! Thanks for the help guys! Opening it as administrator seemed to make it work!

Please Excuse me for my ignorance, but the Gas Gun design Tool doesn't seem to be working. I have read In quite a few articles and forums about this spreadsheet where I can type in values to workout different things such as barrel ratio and that stuff. I am planning on making a new pneumatic cannon,...

"Baldyforks"

Thanks for the feedback. I see where you are coming from with the spring! I might do what everyone else has done (with the storage vessel behind the pilot) then It will be quicker to reload. But my design I have made won't give me much room for that to work!

Thought I would start a new topic on this subject. So I can get as many opinions as possible if this would work or not before I begin buying materials and parts. diagram, sliding valve converted.jpg What if I was to put a sliding hand valve as the pilot valve. One end is connected to port P, and the...

"Technician1002" Thanks, well I might give this a go then. Just thought of a possible problem though.. As we all know - if the pressure is greater at port A than it is at Port P, the pressure difference will pull back the piston and activate the QEV. I am going to have a ball valve (in the location...

"Technician1002" Ah thank you, I think I understand now. So is there some kind of seal on the piston that allows the pressure to get from P to A but not the other way round (unless I modify it of course) diagram, sliding valve converted.jpg Another thing, What if I was to put a sliding hand valve a...

quick exhaust diagram converted.jpg qev1.JPG This Quick Exhaust Valve in this diagram is a shop brought QEV. One of those ones from ebay. I have spent a week or so researching into different ideas of Quick Exhaust Valves. I noticed that allot of people have placed the air compressor/ or large chamb...

I also found stainless steel 40bar qev's at a company called sealexel(india)i am waiting for a reply (i may have to buy bulk) Hey, did they ever reply to you? Did you buy any off them? I have been toying with the idea of using one of those cheap ebay QEV'S, but I would much rather buy a quality pro...

I have built a new air-gun, very similar to my old one, however this one is much stronger and durable. My old one can be found here - http://www.spudfiles.com/pneumatic-cannon-database/topic25658.html converted2.jpg It consists of a powder fire extinguisher used as a stock, which I transfer the pres...

I have spent quite a few days looking through the web at different QEV's, for any alternatives or recommendations. I do not want to build one, I would like to buy one. However, from what I have seen for sale on the internet, most of the QEV's have very low pressure ratings for what I want. I will be...

Since writing this post, I have done allot of research into the pressures that powder fire extinguishers and copper pipe can withstand. I will share my findings in case anyone out there is interested as I was, in case anyone is slightly worried about the pressures as I was.. As you know, different f...

jrrdw wrote:Use the "upload attachment" link in full editor and upload pictures from your computer.

Ah thank you!