what kind of valve is best?

[tjrobison11]

i am about to build a large air cannon that will shoot thinks like tennis balls and golf balls and i was wondering what is the best valve for it, any ideas ?

[mattyzip77]

A dust collector valve

[tjrobison11]

i was looking for one, how much is it and where could i get one, do you think there is a good chance of me finding one in a scrap yard ?

is this good ?

Edited by jrrdw.

[mattyzip77]

I doubt you will find one in a scrap yard. Look on ebay they can range from 15 dollars.to over 100 depending on the deal you find. With these valves or a qev they need no modification. Heres a link to my cannon. Have a look. That one is 3/4 inch it would work but you would have to add a pilot to it and wouldnt be all to powerful.


http://www.spudfiles.com/forums/mattys- ... 23317.html

[Mr.Tallahassee]

If you're up to the task, you might do better performance-wise with a full bore piston valve. I assume you would be using pvc as a barrel so that alone would limit your pressure. A 2.5'' bore valve would be made in at LEAST a 3'' Tee. It would probably be cheaper and more powerful than a store bought, manufactured valve. Beyond that information, use the search. It could really save you money and time.

[jsefcik]

If you're up to the task, you might do better performance-wise with a full bore piston valve. I assume you would be using pvc as a barrel so that alone would limit your pressure. A 2.5'' bore valve would be made in at LEAST a 3'' Tee. It would probably be cheaper and more powerful than a store bought, manufactured valve. Beyond that information, use the search. It could really save you money and time.

pulse valve, will over power and 2 inch piston valve,

it will almost cost the same amout of money if you buy a pulse valve and build the entire gun ,or build a piston valve,

[MrCrowley]

pulse valve, will over power and 2 inch piston valve,

it will almost cost the same amout of money if you buy a pulse valve and build the entire gun ,or build a piston valve,

Where did you get those numbers? Are we talking about a 1.5" porting 'pulse' valve? Because a 2" porting piston valve should have better performance unless you didn't make it very well.

[mattyzip77]

We already had this discussion I thought?? My 1 1/2 inch pulse valve put a mauler valve and supah valve to shame. I posted ggdt results in another thread. Also a 3 inch tee can only handle 120 to 125 psi safely where a aluminum valve can withstand much higher. I put a golf ball through both sides of a steel drum where the other valves only dented it! EDIT My 1 1/2 pulse valve shows close to 700 Proj Vel Ft/sec per ggdt using 155 psi with a golf ball.

[Velocity]

Diaphragm valves VS piston valves is an interesting debate. The diaphragm valve (such as the dust collector valve) is clearly superior in opening time (it is, after all, just a very lightweight piston). However, often times diaphragm valves do not allow for full flow.

I personally own 5 or so of the 1.5" Goyen dust valves, each of which has 3/8" of piston travel for a 1.5" exit. The D/4 rule provides a lower bound on the MINIMUM amount of travel that a piston will need for full flow. For a 1.5" valve, this is 3/8". HOWEVER, referring to this recent thread, I think the general consensus is that the D/4 rule does not apply to tee valves, and a greater amount of travel is necessary for full flow.

I am a little surprised that a dust valve outperformed both the Supah and the Mauler (especially the latter) for golfballs. A 1.5" valve will not provide unrestricted flow to a golf ball barrel (given that you use a 1.5" male adapter, the restriction will be the 1.476" , compared to the GB barrel ID of 1.7 for 1.5" SDR-21). If the Mauler also has a D/4 piston travel, then I suppose this scenario is believable, for the quicker opening time combined with a short barrel (looks like your GB barrel was only 4') might put the diaphragm valve at an advantage here.

But for tennis balls, no way. At full opening, a Mauler certainly will have more flow than the diaphragm valve (likely around 2x, assuming a 2" exit for the mauler and a 1.5" exit for the dust valve), which will make a difference. A 1/4" QEV will open faster than any valve I've ever made, but its not gonna beat a 1" ball valve for launching anything 1" or larger (exaggerated example).

I think its safe to say the diaphragm valve will beat a Mauler/Supah for any barrel SMALLER than 1.5". In the range of 1.5" to 2", its iffy, and for 2.5" and above the larger porting of the listed piston valves will let them prevail.

(All of this assumes that all three valve types are in working order; if the valve is not operating properly, as may have been the case for the one that allegedly was outperformed by the diaphragm valve, then all bets are off).

[jsefcik]

Diaphragm valves VS piston valves is an interesting debate. The diaphragm valve (such as the dust collector valve) is clearly superior in opening time (it is, after all, just a very lightweight piston). However, often times diaphragm valves do not allow for full flow.

I personally own 5 or so of the 1.5" Goyen dust valves, each of which has 3/8" of piston travel for a 1.5" exit. The D/4 rule provides a lower bound on the MINIMUM amount of travel that a piston will need for full flow. For a 1.5" valve, this is 3/8". HOWEVER, referring to this recent thread, I think the general consensus is that the D/4 rule does not apply to tee valves, and a greater amount of travel is necessary for full flow.

I am a little surprised that a dust valve outperformed both the Supah and the Mauler (especially the latter) for golfballs. A 1.5" valve will not provide unrestricted flow to a golf ball barrel (given that you use a 1.5" male adapter, the restriction will be the 1.476" , compared to the GB barrel ID of 1.7 for 1.5" SDR-21). If the Mauler also has a D/4 piston travel, then I suppose this scenario is believable, for the quicker opening time combined with a short barrel (looks like your GB barrel was only 4') might put the diaphragm valve at an advantage here.

But for tennis balls, no way. At full opening, a Mauler certainly will have more flow than the diaphragm valve (likely around 2x, assuming a 2" exit for the mauler and a 1.5" exit for the dust valve), which will make a difference. A 1/4" QEV will open faster than any valve I've ever made, but its not gonna beat a 1" ball valve for launching anything 1" or larger (exaggerated example).

I think its safe to say the diaphragm valve will beat a Mauler/Supah for any barrel SMALLER than 1.5". In the range of 1.5" to 2", its iffy, and for 2.5" and above the larger porting of the listed piston valves will let them prevail.

(All of this assumes that all three valve types are in working order; if the valve is not operating properly, as may have been the case for the one that allegedly was outperformed by the diaphragm valve, then all bets are off).

you hit it right on the nail!!!

[tjrobison11]

thanks for all of the information guys, but which one would you say is the most cost effective ?

[jsefcik]

thanks for all of the information guys, but which one would you say is the most cost effective ?

being cheapest? id say the dust collector valve, no building of a piston required, just a barrel ,chamber and trigger assembly

[MrCrowley]

We already had this discussion I thought?? My 1 1/2 inch pulse valve put a mauler valve and supah valve to shame. I posted ggdt results in another thread. Also a 3 inch tee can only handle 120 to 125 psi safely where a aluminum valve can withstand much higher. I put a golf ball through both sides of a steel drum where the other valves only dented it! EDIT My 1 1/2 pulse valve shows close to 700 Proj Vel Ft/sec per ggdt using 155 psi with a golf ball.

I'll refer to Velocity's post on this one as he covered all I would have said. For projectiles 2" or above, I'd lean towards a 2" porting valve over a 1.5" porting valve. Though, if it is practical and efficient to use pressures well above 125PSI, the dust collector valve would have the advantage.

tjrobison11,

If you can find these dust/pulse valves for a good price on eBay, you can get it in a decent time frame and you're not looking to shoot anything above 2" in diameter; go with the dust/pulse valve. If you want to make your own valve to get some priceless hands-on experience and shoot large projectiles, make your own valve.

[tjrobison11]

We already had this discussion I thought?? My 1 1/2 inch pulse valve put a mauler valve and supah valve to shame. I posted ggdt results in another thread. Also a 3 inch tee can only handle 120 to 125 psi safely where a aluminum valve can withstand much higher. I put a golf ball through both sides of a steel drum where the other valves only dented it! EDIT My 1 1/2 pulse valve shows close to 700 Proj Vel Ft/sec per ggdt using 155 psi with a golf ball.

I'll refer to Velocity's post on this one as he covered all I would have said. For projectiles 2" or above, I'd lean towards a 2" porting valve over a 1.5" porting valve. Though, if it is practical and efficient to use pressures well above 125PSI, the dust collector valve would have the advantage.

tjrobison11,

If you can find these dust/pulse valves for a good price on eBay, you can get it in a decent time frame and you're not looking to shoot anything above 2" in diameter; go with the dust/pulse valve. If you want to make your own valve to get some priceless hands-on experience and shoot large projectiles, make your own valve.

thanks i will go with a dust collector valve and just shoot golf balls