SpudFiles

As keeping with custom, I made some modifications to my hybrid and went handheld with it.

Specifications
Chamber--1' of 1" galvanized pipe
Barrel--4' of 1/2" Copper until I buy a 1" barrel
Valve--1" Burst Disk
Ignition--Camera Flash circuit dumped through Bosch ignition coil
Fuel--Propane
Mixes--4x

A Few Notes
I have only fired this once, as my pressure gauge broke, and I just shot a milk jug filled with water.

The stock is made of three pieces of 1/2" particle board glued together. I was out of plywoood when I made this, so I just went ahead and used the particle board. It has held together very well, although I should have used some nice marine plywood, and stained it.

The only downside to this gun is the weight. It must weigh 15 lbs, but a sling may be employed to make hip shooting easier.

Wow... That looks amazing... I love that stock on there! Holy crap 25 lbs is a heavy gun

Looks like a nice blaster. good job making it handheld.
I never would have thought to use particle board for a stock but it looks like you've made the most of it.
Maybe you could coat it with some laquer or fiberglass for auto-body.

I wonder if the tank could be mounted somewhere else like in a back pack or belt to cut down on weight? Also if you leave it there you could fit it into a pvc(forget which size holder).

Woah cool!

Try getting a nice sturdy bi-pod on it .

Thunderlord: I might put the propane bottle in a piece of 3" PVC and keep it where it is on the launcher.

I am pretty surprised that I could shape the particle board as well as I did, I thought for sure that it would just fall apart.

I just added a trigger guard and I will try to get a picture up soon.

Very nice job
25lbs seems like a bit of an over estimation but I would image that to be quite heavy.
What is the recoil like?

that looks good.
any damage shots? (from the milk jug)
what did you shoot?
any velocity things?

I edited the original post, changing the weight from 20 lbs to 15lbs.

Bigbob: I can't really say what the recoil is like, as the one shot I did was flawed for a number of reasons.

-The pressure gauge had already broken, so I had no idea how much propane and air I injected, making it amazing that it actually fired.
-I had no aluminum foil, so I used the lid of a cream cheese tub as my burst disk, but it didn't really burst, it just developed a crack down the middle.

This may not seem to have a bearing on the recoil, but I wasn't paying attention to the recoil when I did this one shot, and the shot was delayed about 2 seconds after I flipped the switch, so it caught me off guard.

Simply said the recoil wasn't drastic or painful, just normal.

Haven't seen this done yet but if you want to stick with the metal look there's a metal thinwall EMT Conduit (for electrical)pipe that would probably fit a propane tank.

Looks great! Do you think having a long chamber like that is alright though considering DDT?

@noob of noobs: I would say yes, it's probably safe from DDT.
The general consensus these days is that the DDT run up distance in propane/air mixes is long enough that a chamber would need to be impractically long relative to it's diameter for such a thing to occur, even at high mixes.

But in propane/oxy mixes, it's supposed to only be around 2 or 3 chamber diameters...

But in propane/oxy mixes, it's supposed to only be around 2 or 3 chamber diameters...

I don't quite believe that figure for some reason. I have a 2" x 24" chamber on a little mortar type thing I made, and it hasn't experienced any damage with a single ignition point at the front and 3x oxy/propane. Also, SB15's 15psi precharge (roughly 8x) oxy/MAPP hybrid with a 1.25" x 12" chamber never failed, bulged, or even cracked.

yea i wouldn't be too worried about DDT if i were him

DDT never even crossed my mind when building this gun, because I wasn't going to use oxy/propane, or anything else along those lines.


Related to the gun, I hope to make a bipod in my tech class. A scope may also be in the cards, but I would need to mount it pretty high up.

great gun
just because of the weight a sling may work but you should mount it on a stand or a tripod that would be sweet