Page 1 of 2

Help with a QEV

Posted: Tue Aug 07, 2012 5:21 am
by AircannonSweden
I made this QEV yesterday and I can't get this sealing leak-free...what can i use for material? The piston is kinda big but it is still under construction

Piston and housing

Image

"sealing"

Image

Image

Posted: Tue Aug 07, 2012 5:40 am
by MrCrowley
Is the piston even larger in diameter than the seat?

Posted: Tue Aug 07, 2012 5:44 am
by jackssmirkingrevenge
By "piston" do you mean half-digested piece of rubber superglued to a capacitor :D

Posted: Tue Aug 07, 2012 5:58 am
by AircannonSweden
MrCrowley: The piston fits perfect in the housing,when i push the piston forward it is air-tight but when i fill a tank with air(3 PSI or something)it will leak...Well,i should see if a find another material

jackssmirkingrevenge: Haha yes :D i have made one more piston that is much shorter,i have taken out that material in the capacitor and filled it with hot-glue insted...I going to Stockholm today and i maybe found something there ;)

Posted: Tue Aug 07, 2012 6:01 am
by MrCrowley
3PSI isn't enough, try 30.

Posted: Tue Aug 07, 2012 6:16 am
by jonesy42
You can buy QEV's on ebay for less than $15! (search quick exhaust valves).
I don't know why people bother "making" qev valves when
they are fairly cheap to buy?....,But thats in my opinion of course,
good luck anyway :wink:

Posted: Tue Aug 07, 2012 8:06 am
by Crna Legija
jonesy42 wrote:You can buy QEV's on ebay for less than $15! (search quick exhaust valves).
I don't know why people bother "making" qev valves when
they are fairly cheap to buy?....,But thats in my opinion of course,
good luck anyway :wink:
homemade one IMO preform better at least well made ones.

Posted: Tue Aug 07, 2012 8:40 am
by AircannonSweden
MrCrowley: Thank you,it worked with higher preassure :D

jonesy42: I have already built a cannon with a QEV from ebay :D

Posted: Tue Aug 07, 2012 3:03 pm
by Mr.Tallahassee
jonesy42 wrote:You can buy QEV's on ebay for less than $15! (search quick exhaust valves).
I don't know why people bother "making" qev valves when
they are fairly cheap to buy?....,But thats in my opinion of course,
good luck anyway :wink:
Good luck finding a QEV with porting larger than an inch for less than an arm and a leg. :wink:

Posted: Tue Aug 07, 2012 7:20 pm
by mattyzip77
Do you go on e bay? I just got two 1 1/2 inch pulse valves for 30 dollars shipped. I have never seen a qev bigger than 3/4 of an inch. After that size they are called diaphragm valves.

Posted: Tue Aug 07, 2012 8:25 pm
by Mr.Tallahassee
mattyzip77 wrote:Do you go on e bay? I just got two 1 1/2 inch pulse valves for 30 dollars shipped. I have never seen a qev bigger than 3/4 of an inch. After that size they are called diaphragm valves.
A diaphragm valve is not the same as a piston valve. Apples and oranges cannot be compared. They are similar in principal but they aren't the same. What I'm saying is that I can go buy steel pipe and fittings and make a 2'' ported piston valve for less than the cost of a commercial 2'' valve that also performs better. Why buy something and make do with it when you can build a better one the way you want? The latter just makes more sense to me.

Posted: Tue Aug 07, 2012 8:35 pm
by dewey-1
mattyzip77 wrote:Do you go on e bay? I just got two 1 1/2 inch pulse valves for 30 dollars shipped. I have never seen a qev bigger than 3/4 of an inch. After that size they are called diaphragm valves.
Mead make a 1 inch.
Very expensive though.
http://www.mead-usa.com/products/detail ... =46&type=3

Posted: Tue Aug 07, 2012 8:38 pm
by PVC Arsenal 17
jackssmirkingrevenge wrote:By "piston" do you mean half-digested piece of rubber superglued to a capacitor :D
That is priceless. Clever job OP

Posted: Tue Aug 07, 2012 9:56 pm
by mattyzip77
dewey-1 wrote:
mattyzip77 wrote:Do you go on e bay? I just got two 1 1/2 inch pulse valves for 30 dollars shipped. I have never seen a qev bigger than 3/4 of an inch. After that size they are called diaphragm valves.
Mead make a 1 inch.
Very expensive though.
http://www.mead-usa.com/products/detail ... =46&type=3
Dewey your always making a liar out of me... :D

Posted: Sun Aug 12, 2012 10:38 am
by AircannonSweden
This is what i came up with,it is piloted by a 1/2" ball valve!

Image

Image

Image