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Tired and need your HELP. Please take a look.QEV

Posted: Sun Oct 19, 2008 2:14 pm
by iljy
Hello everyone im new here and if by asking help here im breaking any forum rules i hope u guys forgive me and help me move this topic.

Im currently trying to be build a sniper airgun installed with a qev it is my first time and im new into all this and i hope u guys can help me expand my knowledge and enlighten me on my problems.

1st off a slight example of my goal. Here is the picture:Image
I did not make this gun and i do not take any credit for anything of it.

Ok i have just started building my gun and im working on the QEV i have got a few questions i have actually tried talking to the person who made the gun he helped me the first day in giving me a tutorial post but its in french and when i translate it to English i can barely understand it. I have tried getting back to the creator of the gun but he doesn't want to reply me.

Here is the link to the tutorial:
This 1 is in french.
http://patator.frbb.net/conseils-aides- ... light=tuto

This 1 is in english.
http://babelfish.yahoo.com/translate_ur ... =Translate

My Questions:

1st question and most important question is how is this thing suppose to work? if someone could explain it to me i would really appreciate it!

2nd question also very important how am i suppose to measure and what to measure? (referring to stage 1 of the guide)

3rd question what should i use for the piston?

4th question how long should the spring be?

5th question what if i only got parts that are all female parts? like the t joint. i cant find a male-female t joint part. Can I improvise?


This are all my questions i hope someone can help me out! Im like getting desperate haha. If u guys need more information or pictures or anything to make things more clear so u can answer my questions please let me know i will try to provide more information.

Posted: Sun Oct 19, 2008 2:42 pm
by Demon
http://www.spudfiles.com/forums/piston- ... t8157.html

1:The 2nd one...

2:Dont use this tutorial because it french plumbing parts and you will not find them in usa or anywhere.

3:wathever you want

4:not very important, at least there is a pressure

5:you can do what ever you want because its homemade !!!!

And next time search a little bit more...

Posted: Sun Oct 19, 2008 2:56 pm
by iljy
Hey thanks for replying. I actually did search the forum but since im new i really don't know what i was looking for i looked at the visual example but i still don't understand what is the spring for and basically what does it do and how does the air flow? The visual example doesn't really help because the example is showing that i fill the air from the side but what happens if i fill the air from the bottom of a T joint? And about the 2nd question it wasn't about the parts its about the measurement. Example: Should the pipe connected to the joint block the T joint hole from the bottom or should it be just on the edge of the hole? or maybe i should just cover half of the hole?

Posted: Sun Oct 19, 2008 6:04 pm
by LCTChamp
Sounds to me like you need to do a lot more research before even thinking about building. Try using the search feature.

Posted: Mon Oct 20, 2008 12:53 am
by iljy
Yes i know i have tried using the search feature but it still doesn't answer my questions. If someone could just give me a link to a basic guide or something that explains what im looking for i would really appreciate it.

Posted: Mon Oct 20, 2008 1:09 am
by Hubb
Do you have an understanding of how a piston valve works? If not, then the research is required. Take a look at Demon's link. That should clear up how a piston valve works.

As far as the measurements, I believe he was referring to the barrel and chamber.

As far as a spring goes, these are not required in a piston valve launcher.

Have you ever built a launcher before? If not, I think this project may be a little difficult. Try building one with a ball valve or sprinkler valve first. If it is your first, you WILL be quite impressed with the results of a modified sprinkler valve.

Also, take a look through the archives and the wiki. Get an understanding first, then start to build.

Posted: Mon Oct 20, 2008 1:16 am
by jackssmirkingrevenge
If you're struggling to understand how the piston valve works and are uncomfortable with making one as your first project, consider that you can buy a complete QEV for not many $$$:

Go to McMaster-Carr's site and look up 3/4" NPT QEV (enter the product number - 6646K23 - in the search field on the top left of the screen), yours for around 20 bucks.

All you have to do is attach your barrel to one end, chamber to another end and exhaust valve to the back ;) nothing to it.

Love the C&H icon by the way :D

Posted: Mon Oct 20, 2008 1:38 am
by iljy
Hey thanks guys this is allot of help! I really appreciate it. I have an airgun before a very simple 1 and i wasn't satisfied with it at all. So i decided to go for something more advanced besides no harming in trying rite?Anyways i really appreciate all the help u guys have given me. THANKS! :)