hybrid cartridge protoype without burst disk

[jackssmirkingrevenge]

At the moment it's 4.4mm steel BBs and 4mm I/D silicone aquarium tubing.

[JDP12]

Ah cool. Thanks.

So is there a cartridge prototype curing in the JSR epoxy oven as we speak?? :violent2: (closes emoticon I could get to an oven )

[jackssmirkingrevenge]

There will be soon, still sipping my morning coffee and sorting through holiday photos for *cough* facebook *cough*

[JDP12]

ahhh alright cool. Looking forward to it! How high of a mix do you expect that tight of a seal to withstand?

[jackssmirkingrevenge]

I've decided to go with a single seal, but curing with a BB already stuck in it. The problem with the first cartridge was that the outer diameter of the seal was identical to the inner diameter of the body, so there wasn't any room for expansion. Should be good for a 7-8x mix, we'll see.

edit: added some pics compared to a 7.62 NATO cartridge, note that I used Araldite, and also you can see the BB in the mouth of the cartridge.

[POLAND_SPUD]

Should be good for a 7-8x mix

I am afraid that might not cut it... I'd say that there is a rule that detents are a lot stronger than expected oh well, you can always use 15-20X mix

[jackssmirkingrevenge]

Ah feck, I went and tested it early now the seal's popped out

[SpudFarm]

Ah feck, I went and tested it early now the seal's popped out

That's too bad..
Did it pop out under fueling or the actual combustion pressure?

[jackssmirkingrevenge]

Fuelling, it came out with the syringe nozzle.

I might just stop pissing around with this small size and make a 12 gauge shell sized round (similar to one of mypneumatic cartridge prototypes) chambered in 6mm.

[JDP12]

I would be in favor of that. Power will leap incredibly, and then you can make one of these:

[Gaderelguitarist]

Forgive me if this is idiotic in any way, but isn't silicone notoriously difficult to adhere to?

[jackssmirkingrevenge]

Forgive me if this is idiotic in any way, but isn't silicone notoriously difficult to adhere to?

You can chip off bits with a blade and improve its chances of sticking in the same way you would abrade a surface.

I was fully intending to make something but a rather lovely friend from the Motherland is here at the moment and we went out and got completely smashed let's see if I can cook something up before she recovers.

And yes, a replica of Chigurh's shotgun is definitely on the list

edit: while it would be a plus, I've come to the conclusion that trying to use the projectile seal for filling is not practical. Using some simple parts I managed to make a small check valve that works very well, using some parts from a cigarette lighter valve. Making my n^th prototype as we speak

[SpudFarm]

That will work but ruins the simplicity somehow.

I made a diagram of what I have been thinking about.

The valve is made from a small rod that has a washer on the end (Perhaps you can epoxy it to the rod?) and a small rubber seal of some sort. The chamber electrode can probably be made from a piano wire section or something like that.

The seal can probably be made simpler by slipping a tight fitting rubber tube over the rod on the inside of the chamber, shouldn't need the washer.

I won't work more on it before I have your response to it It's kind of lacking detail right now.

[jackssmirkingrevenge]

Unfortunately, you do lose simplicity, but it's still simple enough to make 15-20 of them which is all I will need really.

As to your idea, quite close to the original concept

[SpudFarm]

As to your idea, quite close to the original concept

Yes but I think it is the best solution if you can get it to work. Since it was the original idea before you decided to try a projectile checkvalve that didn't work it deserves a try or five

The valve you are thinking about using now can probably be made easier and cheaper by using .22 cartriges with a hole drilled through the back. Just dent it at the "front" to stop the ball bearing from popping into the chamber during fueling.
You won't be asked why you buy so many lighters atleast

Well, good things usually comes from brain storms so I gave it a try.