400psi piston vavle

POLAND_SPUD · Fri Jan 11, 2008 6:41 pm

I am just wondering... what type of fittings do you use most of the time ? steel, brass or iron ? iron is likely to have the lowest burst pressure of all three right ? anyidea what is the operating pressure of 1/2" iron fittings becasue I have LOTS of them

ALI i've already taken my QEV to 250 psi... but I am still waiting for your results before I go above 300 or near 400 psi...

sorry I am too afraid of dammaging my precioussssss QEV

ALIHISGREAT · Sat Jan 12, 2008 2:30 am

POLAND_SPUD wrote:I am just wondering... what type of fittings do you use most of the time ? steel, brass or iron ? iron is likely to have the lowest burst pressure of all three right ? anyidea what is the operating pressure of 1/2" iron fittings becasue I have LOTS of them

ALI i've already taken my QEV to 250 psi... but I am still waiting for your results before I go above 300 or near 400 psi... sorry I am too afraid of dammaging my precioussssss QEV

ermm well iron is the cheapest and brass is used more for smaller sizes and i haven't used steel yet.

and its alright for me to damage mine but not for you to damage yours

and if your polish QEVS are soo cheap maybe you should try with yours first...

POLAND_SPUD · Sat Jan 12, 2008 10:08 am

OK I've tried first.....

today I finally had some time for spudding.... I've fired atleast 15 shoots at 300psi.... and one at ~ 340 psi
I openned the QEV and piston still looks perfectly ok... so i assume that there wouldn't be any problems with using QEVs at 400 psi

ALIHISGREAT · Sat Jan 12, 2008 12:41 pm

POLAND_SPUD wrote:OK I've tried first..... today I finally had some time for spudding.... I've fired atleast 15 shoots at 300psi.... and one at ~ 340 psi
I openned the QEV and piston still looks perfectly ok... so i assume that there wouldn't be any problems with using QEVs at 400 psi

hmm i didn't foresee any problems but i think the problems (if any will come after lots of use at 400psi but that shouldn't be a problem as i won't be using 400psi all the time.

POLAND_SPUD · Sat Jan 12, 2008 2:41 pm

BTW I found this http://aukcja.onet.pl/show_item.php?item=294026716
16X1 mm brass pipes.... for about 4.5 pounds for 1kg

any idea what is the operating pressure of brass pipes ? higher than copper or lower ?

DYI · Sat Jan 12, 2008 2:48 pm

Depends what kind of brass pipe. All copper tube 1" and under has a burst pressure of over 3kpsi. SCH 80 brass pipe would be incredibly strong, but horribly expensive. Copper tube is more economical than brass pipe in all sizes. Brass just isn't worth it. Steel is better than brass for non-corrosive applications, and far, far cheaper.

Normal 1/2" SCH 40 malleable iron fittings are rated for 150 psi, and have a burst pressure of well over 2kpsi. I've personally used malleable iron fittings in 2" size up to 470 psi, repeatedly, with no ill effects, even in extreme cold.

POLAND_SPUD · Sat Jan 12, 2008 2:52 pm

DYI thx....
but i don't get it brass is not practical ? It would be great for barrels becasue there are lots of sizes available..... and for chambers too - 24X4 mm pipe for 4 pounds per 1 kg... it's even cheaper than the 16 mm one... and cheaper than steel...

DYI · Sat Jan 12, 2008 2:56 pm

Well, there is no such thing as copper pipe for one thing. If you tell me the schedule of the pipe, or dimensions, as well as the fatigue strength of the brass that the pipes are made of, I can give you a rough idea of their burst pressure.

POLAND_SPUD · Sat Jan 12, 2008 3:41 pm

soo copper pipes are acctually brass pipes ? sorry I've been using steel only so I don't know much about copper pipes/fittings......

what about this size, 24 mm either ID or OD, it's not stated anywhere; 4 mm thick wall...
it is M63z4 (it's a name of alloy I found that it is more often described as CuZn37 Rm370; when I googled CuZn37 it turned out that the number 37 tells how much Zn there is in this alloy.... )
http://www.imnr.ro/aliaj13eng.htm - and this suggest that it is possibly the 'standard' brass used in pipes

ALIHISGREAT · Sat Jan 12, 2008 3:56 pm

could someone please GGDT this gun for me because i can't get it for various reasons.

28mm x 50cm chamber
25mm piston with a 20mm porting piloted by a 1/2" qev
20mm x 1.5m barrel (17.5mm id)
operating pressure 400psi

ammo 0.68 paintball (17.27mm i think)
anything i have missed?

thanks Alasdair

DYI · Sat Jan 12, 2008 4:10 pm

There is copper tubing, but no copper pipes.

@Ali: I can't do the GGDT because I don't know the QEV specs. I'm sure someone around here does though.

al-xg · Sat Jan 12, 2008 4:21 pm

7.8CV flow ; 2ms open time something like that

ALIHISGREAT · Sat Jan 12, 2008 5:35 pm

DYI wrote:There is copper tubing, but no copper pipes.

@Ali: I can't do the GGDT because I don't know the QEV specs. I'm sure someone around here does though.

well Al-XG gave some specs and it doesn't have to be spot on.

POLAND_SPUD · Sat Jan 12, 2008 6:19 pm

I have no idea how much does 0.68 paintbal weights so I put 15g projectile instead.
with 2 grams projectile instead - GGDT shows 384 m/s

ALIHISGREAT · Sat Jan 12, 2008 7:28 pm

thanks, they were the kind of performance figures i was hoping to see

i think paintballs are 3-4g

and i might just have to make myself some 15g ammo because 330j is one hell of alot of power

edit: could you also model it with a lighter piston because i'm using hdpe which is ~0.94/cm3 so i would need a 50cm3 piston to do that which would be more than 10cm long

so a 5cm piston would be 23g

and the valve is a barrel not chamber sealer thanks Alasdair