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qev vs piston

A place to ask general spud cannon related questions.
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which is better qev or piston

qev
12
86%
pistion
2
14%
 
Total votes : 14
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qev vs piston

Unread postAuthor: twizi » Tue Dec 02, 2008 7:35 am

im building a high powered airsoft sniper rifle should it be qev or piston what has faster opening time which is better please comment u can sugest different valves
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Unread postAuthor: jackssmirkingrevenge » Tue Dec 02, 2008 8:03 am

A QEV is a commercially manufactured piston valve, so if you want to fork out a bit more and save yourself some work, go for a it ;)
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Unread postAuthor: frankrede » Tue Dec 02, 2008 8:04 am

A qev will work better.
They are available in small sizes and are better than most piston valves.
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Unread postAuthor: POLAND_SPUD » Tue Dec 02, 2008 9:37 am

keep in mind that making a piston valve costs money too...
so don't listen to people who say that piston valves are better because they cost nothing...

you have to buy all the parts and building takes some time... what is more, qevs simply have better performance than homemade piston valves... so all in all it is better to use QEVs... (unless you need a large porting valve (bigger than 3/4") if that is the case it's much cheaper/better to build your own piston valve)

spend some time searching for places selling QEVs you can find shops that sell them really cheap
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Unread postAuthor: jackssmirkingrevenge » Tue Dec 02, 2008 10:47 am

POLAND_SPUD wrote:keep in mind that making a piston valve costs money too...
so don't listen to people who say that piston valves are better because they cost nothing...

you have to buy all the parts and building takes some time... what is more, qevs simply have better performance than homemade piston valves... so all in all it is better to use QEVs...


That's a bit of a sweeping generalisation. I can make an epoxy piston for a tiny fraction of the cost of a QEV with a performance that's just as good, however for someone not willing to invest the time and effort in materials etc. then a QEV is a perfectly acceptable choice for what is not really that much money.

Also, if you're working on something more complex than a single-shot launcher, having a ready-made QEV will leave you more capacity to dedicate attention to more challenging parts.
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Unread postAuthor: POLAND_SPUD » Tue Dec 02, 2008 11:48 am

That's a bit of a sweeping generalisation. I can make an epoxy piston for a tiny fraction of the cost of a QEV with a performance that's just as good, however for someone not willing to invest the time and effort in materials etc. then a QEV is a perfectly acceptable choice for what is not really that much money.
LOL JSR not everyone is an epoxy god like you.... epoxy costs quite a lot plus you have to know how to use it (which means you first have to spend some $ and practise using it)....

overall I agree with your reasoning - in some circumstances and for some of us it might be cheaper to make your own piston valve but not much... sometimes it's better to spend that 5-10$ more and buy a product that does perfectly what it is supposed to do
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Unread postAuthor: jackssmirkingrevenge » Tue Dec 02, 2008 12:19 pm

POLAND_SPUD wrote:epoxy costs quite a lot plus you have to know how to use it (which means you first have to spend some $ and practise using it)...


The thing with epoxy is most people look at the unit cost per container, ignoring the fact that the actual amount you use per project is very little.

I remember paying around $100 for 4.5 kilos a few years ago, a typical mini-piston airsoft calibre launcher (piston + endcaps) doesn't use more than 30 grams of epoxy, that works out at just 66 cents!

You have point though that until you get used to working the material, there might be some waste on the way :roll: useful to note though that epoxy fragments from unwanted projects make an excellent filler when broken up and added to an epoxy mix.
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Unread postAuthor: cheeseboy » Tue Dec 02, 2008 4:01 pm

okay... I cant vote yet due to the fact of my just having joined, but in your case - that of an airsoft gun - a QEV would be better, because your chamber probably has a small diameter. but I like piston valves for the big guns :twisted: but in your case i would vote for QEV
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Unread postAuthor: twizi » Tue Dec 02, 2008 4:27 pm

if it helps im building semi auto my chamber is 9oz pb tankand 270psi my barel probally will be a brakeline will this work?? about how many fps??also any suggestion on were to get good cheap qev
thanks for comments
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Unread postAuthor: MaxuS the 2nd » Tue Dec 02, 2008 5:16 pm

You're being a bit general there.
Yes, you have a 9oz tank at 270psi with a Brakeline barrel.

But that's like saying:

I got a car,
It's got 4 wheels
It weighs 1500kg..

How fast will it go?
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Unread postAuthor: twizi » Tue Dec 02, 2008 5:34 pm

what should i use a qev or pistion also were to get a good qev also should i use a brakline or should i get somthin else




thanks
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Unread postAuthor: cheeseboy » Tue Dec 02, 2008 5:46 pm

I personally like mcmaster- Carr, its a bit overwhelming when you first go on it but it is really a great source of parts, luckily for me I know the people that run my local hardware store so they can get me stuff cheap, so other than mcmaster I cant help you. :oops:

edit: about the brake line, they are actually a little bit to big, but still work well. but if you really want a good looking high performance barrel invest in a length of 6mm copper its great, expensive - at least in Australia- but great
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Unread postAuthor: twizi » Tue Dec 02, 2008 8:02 pm

what about in america any good barrels for a cheap hard to bend barrels that about a yard long is this a good barrel length for a sniper??



also any good free design programs to design my rifle on???ive been usen paint really bad
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Unread postAuthor: Gippeto » Tue Dec 02, 2008 8:44 pm

What kind of "good free design program" did you have in mind?

GGDT is free, and in my opinion, it's a great tool to have.

http://www.thehalls-in-bfe.com/GGDT

Or, are you looking for CAD software?

Just google "free cad"(without the quotes of course). There are many to choose from.

And please,..try using the spell check button. :)
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Unread postAuthor: twizi » Tue Dec 02, 2008 8:49 pm

thanks gippeto im pickin one right now
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