30 replies to this topic

[Mr BadWrench]

you need
1 3/4in to 1/2in pvc reducer
1 1/2in pvc Tee
1 #10/24x2.5 stainless steel screw
2 #10 nuts
1 #10 washer
1 3/8in faucet wahser ( i used a 1/2in and had to trim it down for the trigger to function.
1 piece of 1/2in cpvc
1 piece of 1/2in pvc
1 spring
hotglue
loctite

when buying pvc and cpvc make sure they easily telescope together... check through the pile in the stor sizes vary by batch and brand.

cut 1/2in long pieces of pvc and cpvc and put a piece of pvc into one end of the 1/2in pvc tee and the cpvc into the 1/2in side of the reducer.




make this


Modify spring like so

opening the final 2 coils so it will seat on the 1/2in cpvc inside the coupler




thread the screw into the washer and drop them into the big side of the cpvc coupler


put the spring on the other side and put a nut/washer/nut combination on carefully tightening until there is decent tension on the washer making a nice airtight seal. test by blowing through valve and opening wiht your finger... superglue or use threadlock to hold nut in place



glue a 2in piece of cpvc over the rest of the screw.






put the whole thing inside the Tee with the 1/2in cpvc and 1/2in pvc pieces sliding easily... I hotglued this part so it could be disassembled.


USE PVC CEMENT AND PRIMER on all air tank connections!!!!!

I do not have a permanent pressure pump yet.

Edited by Mr BadWrench, 19 January 2009 - 03:51 PM.

[Mr BadWrench]

had a small assembly error that casued me to have to cut it open...



made carbine which I like even more....

Edited by Mr BadWrench, 18 January 2009 - 07:45 PM.

[thaygor]

badwrench this thing is awsome! I can't wate to see it at the next war we are boath at.

[rork]

How does it hold pressure? This is remarkably similar to a project I've worked (unsuccessfully) on on and off for a while now.

[bobbybilly60]

Reminds me of CaptainSlug's Dchap-1. I like the trigger even more.

Edited by bobbybilly60, 19 January 2009 - 01:15 AM.

[Mr BadWrench]

How does it hold pressure?

the inside of a 3/4to 1/2in reducer is chamfered and the faucet washer is tapered, the shapes make it self centering. the spring gives just enough pressure for a seal...

Don

[Frankie27]

Very Nice. I only just built my first homemade a few days ago with a very poorly lubricated ball value as the trigger (stupid aussie hardware stores, you know we only have one major chain of hardware store?) Anyway, looks good, just wondering how many pumps this takes to fill and what sort of range it gets. I'm going to build, hopefully this exact thing.

Edit: Looking at the diagrams, 3/4 CPVC is the air tank so what is the 1/2 PVC it the top. By the looks of it it looks like a built in RSCB clip?

Edited by Frankie27, 19 January 2009 - 06:32 AM.

[Galaxy613]

Sweet job! I wonder if we could repurpose the trigger valve into a check valve for a homemade pump.

Anyways, next time I stop by ACE I'm getting the supplies for this.

Edited by Galaxy613, 19 January 2009 - 09:21 AM.

[imaseoulman]

Two questions:
1) How did you find CPVC and PVC that telescope easily? I've never been able to find that. I've always had to sand the heck out of the inside of the PVC or the outside of the CPVC.

2) When you depress the trigger, what prevents the air from rushing out of the trigger? Do you get some air loss? Is it an insignificant amount?

Very nice design, though. If there isn't signifcant leaking out of the front, you've effectively created an air tank/dump valve that really only needs one seal (instead of the second seal around the firing pin).

This looks very interesting. If I can ever find telescoping PVC/CPVC, I'll give this a try.

Also, instead of using a PVC TEE to house the trigger assembly, you could use a PVC cross. You could then seal off the bottom and use that to attach a handle. Of course there are other option for adding a handle- that's just the first one that came to mind.

Oh yeah, last question, how strong is that spring?

[Mr BadWrench]

1) How did you find CPVC and PVC that telescope easily? I've never been able to find that. I've always had to sand the heck out of the inside of the PVC or the outside of the CPVC.

I carry a 1in piece of my petg, 1/2in pvc and 1/2in cpvc in my pocket at all times. I buy 1/2in pvc with red writing on it at home depot and cpvc that fits my fbr at lowes. Sometimes I have to sort through the rack to find a piece, Usually the 5ft stuff fits and the 10ft stuff does not, im assuming the 5ft pieces are "seconds" from the factory.

2) When you depress the trigger, what prevents the air from rushing out of the trigger? Do you get some air loss? Is it an insignificant amount?

The pvc/cpvc coupling makes a fair seal, If I plug the barrel all the air will go out the trigger... but if you look at my drawing, I put a rubber cap over the end of the tee that the trigegr is on... a balloon or another certain flexible rubber device works fine.

Very nice design, though. If there isn't signifcant leaking out of the front, you've effectively created an air tank/dump valve that really only needs one seal (instead of the second seal around the firing pin).

This looks very interesting. If I can ever find telescoping PVC/CPVC, I'll give this a try.

Also, instead of using a PVC TEE to house the trigger assembly, you could use a PVC cross. You could then seal off the bottom and use that to attach a handle. Of course there are other option for adding a handle- that's just the first one that came to mind.
adding another barrel?

Oh yeah, last question, how strong is that spring?
the spring is quite stiff, maybe 6lbs its stiffer than any of the shock springs from my 10th scale rc cars. ill get more info on my parts soon.



Don

Edited by Mr BadWrench, 19 January 2009 - 03:43 PM.

[Galaxy613]

How do you pump it? Do you carry bike pump around the field, or what?

[analogkid]

Two questions:
1) How did you find CPVC and PVC that telescope easily? I've never been able to find that. I've always had to sand the heck out of the inside of the PVC or the outside of the CPVC.

If you have a 5/8" spade drill bit, like this one:



you can usually bore the PVC out, if you're careful. It takes a bit of effort, but its much faster than sanding.

Edited by analogkid, 19 January 2009 - 02:31 PM.

[Mr BadWrench]

How do you pump it? Do you carry bike pump around the field, or what?

im using a ball pump and im experimenting..... since no one has done alot of research on pumps I have not decided on what I will use and I will post a full writeup on my results.

[venom213]

Does the CPVC have to be completely airtight inside the piece of PVC on the "trigger" part? I am very interested in building something like this, but that air-tightness might be difficult to achieve.

[Galaxy613]

Does the CPVC have to be completely airtight inside the piece of PVC on the "trigger" part? I am very interested in building something like this, but that air-tightness might be difficult to achieve.

That's where that rubber cap comes in. If you can't get a perfect airtight seal, you can just use that catch-all.

[rork]

The beauty of this kind of valve is that the front doesn't have to seal perfectly, because it's easier for the air to go down the barrel than out the front of the valve.

[Galaxy613]

BTW, you never anwsered how far it fires. How far does it fire, and how does it compare to other air guns such as AT2k's? (if you have one, I donno)

[Mr BadWrench]

BTW, you never anwsered how far it fires. How far does it fire, and how does it compare to other air guns such as AT2k's? (if you have one, I donno)

I don't want to be rude but its January in Ohio and my stefens are white. I have not given any specific measurements for my cpvc tank or my pressures because This writeup is mostly for my air valve, It seals good and dumps fast and I have given every detail of its construction.
I have no way if testing guns in a foot of snow when its 17 degrees and the wind is blowing.. I can however shoot a 2ft sq piece of plywood on the opposite wall of my 56ft shop.

Don

[UpperHand]

Two questions:
1) How did you find CPVC and PVC that telescope easily? I've never been able to find that. I've always had to sand the heck out of the inside of the PVC or the outside of the CPVC.

If you have a 5/8" spade drill bit, like this one:



you can usually bore the PVC out, if you're careful. It takes a bit of effort, but its much faster than sanding.

True, but don't hold the PVC with your hands. Period. The drill bits catch sometimes and spin the PVC around. Get a clamp or something, because getting cut with PVC spinning really fast hurts. Trust me, it does.

Edited by UpperHand, 23 January 2009 - 11:43 PM.

[Galaxy613]

Well, my one is almost complete. Some goop is drying and then I'll be able to test it for range and etc... I need to go find my camera and get the USB adapter thing for it.

It is pretty much like Badwrench's, except I'm using a different pump (I haven't found a decent ball-pump yet ;-; ) I also added a ball valve as part of the air tank, I'm hoping it'll allow for two or more shots; and I epoxy puttied the LSFG hand grip to the front and connected the valve to the trigger. I did some low PSI tests with the air tank NOT epoxied togeather and the valve seems to be working fine. I can't wait to test it with 'normal' psi. I am also still running a RSCB, but instead of a 1/2 PVC barrel, I shoved a 1/2 CPVC coupler into the barrel side of the top 1/2'' PVC Tee and I'm using 1/2'' CPVC for the barrel.

Edited by Galaxy613, 27 January 2009 - 11:05 PM.

[Mr BadWrench]

the air tank NOT epoxied togeather

Hey, don't use anything but PVC cement to put your airtank together.... nothing else will hold.... this is not optional... use primer and pvc cement, read the directions on the cars... and endcap or fitting coming off this thing will fuck you up big time.


Don

[Galaxy613]

the air tank NOT epoxied togeather

Hey, don't use anything but PVC cement to put your airtank together.... nothing else will hold.... this is not optional... use primer and pvc cement, read the directions on the cars... and endcap or fitting coming off this thing will fuck you up big time.
Don

You seem to have taken that out of context. The full quote was:

I did some low PSI tests with the air tank NOT epoxied togeather and the valve seems to be working fine.

After those tests I PVC Cemented all PVC parts that will be pressurized. Sorry for the confusion.

Edited by Galaxy613, 28 January 2009 - 10:16 AM.

[CaptainSlug]

True, but don't hold the PVC with your hands. Period.

Dur

It's not a particularly good idea to use a drill press to enlarge an existing hole in soft plastic anyways. You should only be using a flat-blade wood-boring bit to cut out a new hole. If you start with a pilot hole it should not be any larger than the center spike of the bit.

[Shrub]

I for one do not see what the problem is with holding PVC or CPVC with your hands being 13 I can get a good enough grip on the tubing and the torque of trhe drill does the rest do keep in mind that I'm using a 9.2V wireless drill so it isn't as hard to keep steady and still bore out the tubing.

[Draconis]

I for one do not see what the problem is with holding PVC or CPVC with your hands being 13 I can get a good enough grip on the tubing and the torque of trhe drill does the rest do keep in mind that I'm using a 9.2V wireless drill so it isn't as hard to keep steady and still bore out the tubing.

It's nice that you can get a grip on PVC. Now get a grip on proper English sentence structure and punctuation.


It's really NOT a good idea to hold a pipe while you are drilling through it. Metal or hard plastic? Yeah, it works, but use a vice. CPVC, PVC, and PEX are just too flexible to drill through. They flex around the bit and get lodged around it, probably whipping the pipe out of your hands and hitting you with it.