Dual QEV Paintball LAW

[EGOed]

Nice job Peeto, Looking forward to seeing it rip up my paintball field.....you could easily add a tripod and use it as a mortar with sabots and paintballs , or my artillary rounds......I would keep that one with the steel chamber as a mortar and just make another for a LAW...... Nice.

[mark.f]

I like it! What type of barrel supports are those on the barrel? They look like some sort of thermoplastic hangers?

Also, I would agree with everybody else in disagreeing with replacing the chamber with plastic pipe. While plastic is suitable for hobby cannons which are treated gently, I don't think a piece of scenario equipment should be plastic. I would suggest either keeping the steel chamber and just getting over the weight, or replacing the steel pipe with aluminum.

[peeeto]

...you should keep the chamber metal...

nope. will be too heavy. i'm keeping the pressure down near 60 psi (max so far), and the gas supply will be double-regulated. i probably will do the chamber in sch 80, though. i'll keep the metal chamber as backup .

plus, i still have to look in to how much $ to build an aluminum chamber - alum would be operated at higher pressure, so it could be physically smaller, so cost may not be bad...

...seems pricey with the two QEVs.

that's what i thought at first - but they weren't really that much! at McMaster-Carr, the 3/4" is ~$18 , and the 1/4" is ~$12.

with 1" sprinkler valves at $15, the 3/4" QEV alone beats it for price/performance (i think). to spend another $12 doesn't seem too bad to get that much more out of it (IMO anyways).

i'll do up a complete price & source list.

Nice job Peeto, Looking forward to seeing it rip up my paintball field.....you could easily add a tripod and use it as a mortar with sabots and paintballs , or my artillary rounds......I would keep that one with the steel chamber as a mortar and just make another for a LAW...... Nice.

thanks, Ed , and thanks for the help. i'm looking forward to see what you're gonna do with your 2" piston valve - artillery across the entire scenario field! nowhere is safe!!!

Ed's field: http://www.highenergypaintball.com

...thermoplastic hangers?

yup - from the Electrical Dept. at my local Lowes - they were a surprise find for me, never seen em before last week. was using galv. steel rings separated by thrded rod, but these are much cleaner & the action is much smoother.

thanks again everyone for the great feedback.

[peeeto]

ok, i've looked into the cost of using an aluminum chamber buying parts from mcmaster (sch 40, fittings rated to 150 psi):

(pipe lengths 12", guesstimating chamber length ~14" incl. 90d elbow)

2" dia chamber: Cap $13, Pipe $25, El $20, Bushings (2"-3/4") $17
Total: $75

1-1/2" dia chamber: Cap $9, Pipe $16, El $14, Bushing (1-1/2"-3/4") $9
Total: $48

GGDT is telling me that 14" chamber of 1-1/2" pipe will reach the speeds i want at 75 psi with an 18" barrel. perfect!

ok, potatoflinger, i think i'm going with a 1-1/2" chamber! will be a few weeks before i get all the parts, but i'll post back the progress.

[Bluemax]

Nice cannon.

I too play paintball and live the demo/engineer role. I’m also a resident Nerf Nerd for a few local Carolina fields, aka I do inspections and crono LAWs for scenarios.

Not sure if you play in the States, but many fields in the southeast will not allow plastic chambers; even schedule 80 or 120. Most national promoters will not allow them in their scenarios either.

Have you given thought to using a fire extinguisher for your pressure chamber?

[peeeto]

Nice cannon...
...Have you given thought to using a fire extinguisher for your pressure chamber?

thank you! no, i hadn't thought of that - what a good idea.

i assume you have used them before for this application?
1) what are the thread specs? (NPT?)
2) what diameter of the threads i could typically get?
3) have any suggestions as to where to obtain them? or recommendations on make/model?

thanks again

[MrCrowley]

1) The threads you usually can't use. Chances are you'll have to get it welded like I did.

2) They're about 3/4 +- but again they usually don't work. In the odd occasion you may find one that has NPT threads.

3) Weld.

I got two welded and made them into chambers here:
<A HREF="http://www.spudfiles.com/forums/viewtop ... html#56422"> DSGR</a>

[peeeto]

I got two welded and made them into chambers here:
<A HREF="http://www.spudfiles.com/forums/viewtop ... html#56422"> DSGR</a>

ok - thanks for the info. nice gun there - where did you get the extinguishers? or brand info pls...

[MrCrowley]

I got them of http://www.trademe.co.nz and they're 1kg Dry Powder fire extinguishers. I'm in New Zealand so you'll probably have different brands.

[iknowmy3tables]

I've been screwed over by the no pvc rules at local feilds too
If I were going to make a LAW I'd just use a qev and fire extingisher

[ShowNoMercy]

I am not sure whether this would help you but when fire extinguishers don't pass inspection they are recycled. You could probably grab a couple from a junkyard if your willing to deal with slight leaks.

[peeeto]

so, with your experiences, would officials accept an all-metal cust. built aluminum chamber? (no plastic except for the barrel, all Al pipe and fittings rated to 150 psi)

add to the consideration if you slip the the guy $5 and a... oops, uh,... i mean if the law appears well thought-out and well constructed, and has additional safety features? (safety switch (valve), double-regulated CO2 (CO2 (800-1500 psi) --> Palmers Stab --> 120 psi --> Palmers Micro-Rock --> 75 psi (expected op. pressure)))

i think that for maybe a little more than i'd expect to (find and) pay a welder, or have a machine shop make me one, i could just buy the parts i found on McMaster & build me a lighter, smaller chamber - even if i found a FE cylinder for free...

[Bluemax]

My current rig for paintball

Are you in the States? I tapped this FE with only a crescent wrench with a double male threaded adapter from Lowe's. If you have a Lowe’s near you I can get the part number for you.

[peeeto]

...I tapped this FE with only a crescent wrench with a double male threaded adapter from Lowe's. If you have a Lowe’s near you I can get the part number for you.

that's a sweet rig - how do you fill? by remote? very sleek!
i thought i read somewhere here that FE tanks are left-theaded - was yours?
and do you know anything about the brand?
tia,
p

[Bluemax]

The double thread connector: Watts A-524, 7/8" Tube to 3/4" MI Connector with insert compression. Just throw away the insert and compression nut.

FE: I used a Kidde 10BC Kitchen, but I'm sure a Kidde 1A 10BC Recreational will do and a bit cheaper.

Tapping: The thread count of the FE is huge, around 5 per inch. I could never find anything close to that count. Slowly tap the FE with the 7/8" threaded end. The brass threads will cut in to the aluminum (what you want), just take it slow.

To seal: Use a glob (glob being the proper engineering measurement) to seal the connector and the aluminum bottle. I used JB Weld.

HTH and good tapping

*edit*
Yes I fill via a remote line. I run two remotes, one to my cannon and one to my marker. The cannon fills faster than I can breech and load a Nerf. [toot own horn] I can accurately fire 8 Nerfs from my LBV in about 12 secs [/end toot] The tanks love me when I go to a Scenario *insert evil laugh*