Semi-auto propane airsoft gun UPDATE #6

[auxiliary]

[img]The bright green things attached to the dark gray rod which is threaded moves back to close up the back only to open in the front. The rod continues into the turquoise blow forward nozzle which moves back inside the turquoise thing when the entire rod is pulled back. It does not move back far enough to where the o-ring gets out. As the propane hits the turquoise thing, it pushes it forward (chambering airsoft BB) and when it reaches a certain point, the o-ring gets out and the propane rushes through the turquoise thin and shooting the chambered BB.

I decided to attach the turquoise blow forward valve directly to the rod with the o-ring to make it more simple and get a higher rate of fire. (Somewhere like it shoots as fast as you can pull the trigger)


http://www.putfile.com/pic.php?img=7555583

I have now purchased most of the supplies and am working on the piston and air nozzle

Here is a picture of the piston heads and rod attached:

http://www.putfile.com/pic.php?img=7563774
The thing in the middle is supplied for guiding the piston heads into the seal cups. It is vented for efficiency

Here is a picture of the blow forward air nozzle so far...
http://www.putfile.com/pic.php?img=7563775

The pistons heads are made from polycarbonate shaped with the trusty half lathe. (drill and vice)

The rod is threaded stainless steel.

[FeLeX]

Dang man looks tight so far keep up the good work.

[Maniac]

That is some great work cant wait to the it completed.

[auxiliary]

Thanks. One thing I'm not sure about so far is the volume of the spool valve. I don't want to have this thing shoot 600+ fps and give off a large amount of propane gas like 4 cubic inches. Do you guys have a guess to what volume I should use for the spool valve?

[Tom]

Looks good, have you already thought that the gas could freeze the o-rings?
EDIT:I didn't now your pistons where made with a homemade lathe Very impressive work can you take a picture of your homemade lathe? And can you explain a little more what a spool valve is ?. I also think that blow forward-unit is going to be hell to get lined up with the bolt, working with unregulated propane gives allod of pressure. There would be allod of pressure when you fire the valve so your blowforward housing must be very strong. I certainly would use regulated propane(or pro-paine ) so you don't have the risk that when you turn the gun the liquid gas gets in the chamber and freezes the PVC!!!
GR.Tom

[auxiliary]

Do you think I will have a problem concerning that? The Propane is expanding a lot in the spool valve chamber. If I keep air spaces tight yet be able to operate do you think I could pull it off or will that not work?

Would you recommend a propane regulator?

Thanks for that I didn't think of that at all.

EDIT: I should purchase a regulator so what you described doesn't occur.
As for the home made lathe, I am too lazy to get a picture because it is just a power drill on a table vice pointing sideways.

[FordGtMan]

That looks pretty good for the homemade lathe. I tried this once, and got hit in the face with a dowel 8). so how many shots you think you are going to get with one of those propane tanks?

[jon_89]

What is a spool valve? I looked under google and there wans't really a definition of what it does or how it works.

[auxiliary]

fordgtman: I can't find at the moment anything that shows how many shots one could get from propane or green gas, but I'll worry about that later.

Jon: The green thing in this diagram is a spool valve. It releases a fixed amount of air in a burst so there is no waste expenditure of gas. I the diagram if you pull on the rod that sticks outside the left of the chamber, It will pull the entire rod including the green pistons (not the green thing on the very far left) and close the airway or propane way:p in the back and open in the front.
http://www.putfile.com/pic.php?img=7555583

Also the piston heads are actually made of Delrin (Polyacetate) not Polycarbonate (Lexan). I did some research on Delrin and found it is a quite strong plastic and tends to be slippery which I found out when working with it (very annoying).

Here is the picture of what I have constructed so far and the parts in the layout that would be in the gun.
http://www.putfile.com/pic.php?img=7598948

I decided to make the piston head seal pieces that way so the piston heads would still be in that pipe yet be able to release and shut off the regulated propane. In the picture You cannot see the part that seals the rod off from the outside, but I have a picture of it here:
http://www.putfile.com/pic.php?img=7598957

I rode my bike to candyland and back to get the correct fittings to match the propane bleed valve I have. Complements to Ace Hardware. Here is a picture of it attached to the canister with the hose and the part that will tap into the PVC endcap:
http://www.putfile.com/pic.php?img=7606828

[Tom]

Looks very good, also your machining skils are looking very good! I'm pleased to see the working gun

[auxiliary]

Thanks Tom

I've been working out the arrangment of the gun to make it convenient yet stylish and this is the best I had come up with so far...
http://www.putfile.com/pic.php?img=7629918

The contraption at the bottom of the picture is the PVC secondary regulator tank next to the propane tank. I decide to do this so my shots would be more consistent and the pressure could be truly regulated. Not just a bleed valve that slowly hisses air into the gun.

This is a picture of the gun painted:
http://www.putfile.com/pic.php?img=7629959

This here is a crude depiction, but if I got inspired enough I could built this Halo assault rifle/ P90 frame around it out of bent ABS sheet and Poplar wood...
http://www.putfile.com/pic.php?img=7629997

[jackssmirkingrevenge]

coming on nicely, good luck

[Tom]

I woukd ga for the HALO version of the gun, but its going to be a hel of work to make a housing for the magazine! Espacialy the catch system, if your having some plexiglass I would use that for the housing! Captain Slug from nerfhaven uses this to http://nerfhaven.com/forums/index.php?showtopic=9706
GR.Tom

[auxiliary]

Thank you for that link Tom. Captain Slug has incredible skill with that plexiglass. I just might build my magwell out of it! It's the weekend now so I hope to post more pictures of what I will complete.

Well I completed building my regulator tank. The pipes are ABS and I hav two hose fittings on it and a pressure gauge.
http://www.putfile.com/pic/7648108

Here is the under side of the brass fittings in the cap...
http://www.putfile.com/pic/7648107

Sorry about the blurry pictures. The camera just wasn't working properly.
I addition to making the tank, I have made the external seal cup again and with much more care. It is one piece of Delrin with a segment of an airsoft barrel running through it. It provides a strong yet smooth seal. I also just glued the spool valve cups to the inside of the 3/4in pipe.

Here is what I will buy as for the hop-up barrel and mag:
http://www.hotspotairsoft.com/hsastore/ ... g_cart.php

Here is a new and improved diagram:
http://www.putfile.com/pic/7648476

Well, as I built the internal parts of this gun I kept seeing flaws in the design and some things I just couldn't get around. For example PVC pipe doesn't create the best seal because of the inconsistent "topography" of the inside. Also I got around to finally seeing how smoothly the mechanics would work by piecing together everything and it wasn't terrible, but I still want a very smooth operation. I came up with this design which I think is much better then the last because there is only 1 moving part yet it maintains its semi automatic capabilities. Here is the master plan:
http://www.putfile.com/pic/7669520

It is a cross between a slide valve and a spool valve

The PVC coupling is removable so I can remove the internal parts and yet it creates a seal because of the salmon colored gasket o-ring. If you are wondering how the large beveled o-ring can get out with that Delrin cup/stopper in the way, it will just bend and slip past if I yank on it.

The bright side to this is that I get to reuse a couple pieces I have already made (the main one being the external seal tube). Also I can still have that cool looking set-up of the gun.

[Tom]

How os it going with your project?