SpudFiles

Edit: mind the pictures, they're monsters..

I've finished my micro hybrid thanks heaps to those that helped!

Fill is from a schraeder(sp?) valve. Two heavy duty screws and a hot-water system piezo are used to create the spark gap. The PVC sandwhich will hold around 300 + psi (not sure, can't pump it up any more...) but I haven't managed to break it yet. As the motor on my lathe is broken I had to make do with a very limited selection of parts from our local hardware store for the barrel adaptor and burst disk breech. The burst disk breech is basically a threaded sleeve which two fittings screw into. These clamp 2 orings and the burst disk together.

It isn't fired yet, a bit late today. I'll fire it tomorrow probably...

As we don't have propane available I'm going to have to make do with butane. So far this is what I have worked out:

1x: 3.13% butane, atmospheric pressure.
2x: 6.26% butane, 15 psi.
3x: 9.19% butane, 30 psi.
4x: 12.52% butane, 45 psi.. and so on.

Are my ratios correct so far?

Going to fill chamber up with water tonight to find the correct volume.

Oh and btw, I have a remote system for testing this.. So I shouldn't end up dead..I hope..

Bah, uploader is failing..I'll host the images then link them

I've finished my micro hybrid thanks heaps to those that helped!

Fill is from a schraeder(sp?) valve. Two heavy duty screws and a hot-water system piezo are used to create the spark gap. The PVC sandwhich will hold around 300 + psi (not sure, can't pump it up any more...) but I haven't managed to break it yet. As the motor on my lathe is broken I had to make do with a very limited selection of parts from our local hardware store for the barrel adaptor and burst disk breech. The burst disk breech is basically a threaded sleeve which two fittings screw into. These clamp 2 orings and the burst disk together.

It isn't fired yet, a bit late today. I'll fire it tomorrow probably...

As we don't have propane available I'm going to have to make do with butane. So far this is what I have worked out:

1x: 3.13% butane, atmospheric pressure.
2x: 6.26% butane, 15 psi.
3x: 9.19% butane, 30 psi.
4x: 12.52% butane, 45 psi.. and so on.

Are my ratios correct so far?

Going to fill chamber up with water tonight to find the correct volume.

Oh and btw, I have a remote system for testing this.. So I shouldn't end up dead..I hope..

Bah, uploader is failing..I'll host the images then link them



Interior of barrel and chamber



Burst disk seat



Complete cannon

well its definitely small

i'm guessing you will shoot airsoft bbs or air rifle pellets?

ALIHISGREAT wrote:well its definitely small

i'm guessing you will shoot airsoft bbs or air rifle pellets?

Something along the lines of that. I need to find a bit of suitable copper pipe for an extended barrel though. I have some nice moulded darts I made for it.

You won't be dead...from this thing anyway... Perform some shots and let us know your progress.

starman wrote:You won't be dead...from this thing anyway... Perform some shots and let us know your progress.

PVC shrapnel penetrates skin nicely...*remembers back to when his friend jabbed him with a pvc shard..*.

Will do though.

Rofl. That sure is a funny looking little gun.

nice cannon, looks like something a spy would carry around

btw...you have the same thing written twice...

nice pipe bomb =)

Nice. It would good to get some damage pics if you can manage it.

@IlovePsi: Please do NOT say things like that on our forums. It's not funny, and will get us only trouble.

Hey can we have some more info about your Hybrid please, like chamber volume, barrel length etc.

I really like small Hybrids, much more useable than their larger counterparts and imo much more fun to use.

Good luck getting this to fire. You will be fine with the butane too, i use it in all my Hybrids and yeah your mix ratios' should be fine too

Go and make some damage and video it for us

After two 4x shots (it took ages to finally get it to work.. the chamber is far too long) I accidentally dropped it and a large crack (about 3cm formed). So I wont be shooting this cannon again, but I'll definitely make another micro hybrid. The shots were only done with a little wadding but the burst disk noise is nearly deafening.. I'll keep you guys posted on the new one in progress.

I think i might know the problem, maybe it came from using acetone to clean the pvc which made it brittle? It's also possible some of the pvc was exposed to a fair bit of sunlight..things to consider next time.

It's sad to hear it cracked. There could be a numerous amount of reasons why that happened; the foremost one being the drop itself. Hopefully you get a new one up and running with a longer barrel and some video. It’s hard for me to grasp that much power within a few inches! haha

Keep it up! Cheers! 8)

Booo, it sucks when things break. Maybe your next project should make use of stronger materials, ie metal.

CasinoVanart wrote:Booo, it sucks when things break. Maybe your next project should make use of stronger materials, ie metal.

The next one is going well. Construction thread in general hybrid.
I was kind of surprised how easily it cracked..pvc never seems to do that.