"In the world of spuds today"

[DYI]

its cool but how could you use up 4" pipe like that, it could be a high pressure pneumatic that could archive supersonic, only use an fire extinguisher or a used tank or a pvc tank which is fairly safe

-new tank, the current one is part of the hybrid in my sig and weighs twice as much as it needs to because of the rather thick endcaps

I have as much 4" seamless steel pipe available as I want, I get it free from the metalworking room at school, and can get endplates welded on for about $5 by the local welder, with tapped threads and everything. The SCTBDC's 2" ID chamber is bigger than this particular piece, and I don't quite trust the welds at 500 psi constant pressure, considering that the guy who did them doesn't have a certification to weld on pressure vessels.

The hybrid in my sig will definitely be supersonic, even with relatively heavy ammo.

EDIT: 3tables, PVC tanks aren't exactly safe at 300 psi, just FYI

[Novacastrian]

"In the world of spuds today" I made a piston with integral sealing face and a endcap with integral bumper. The size of the piston is 98mm.




The bumper still has to be drilled (in the center) for piloting.

[jackssmirkingrevenge]

Looking extremely good Nova though a little dainty, perhaps some radial ribs between the spool ends would welp support it on impact with the bumper.

The size of the piston is 98mm

That's just shy of 4 inches, what ungodly beast is this component for?

[Gippeto]

Very nice! That sucker is going to "boogaloo" (accelerate very quickly) when you trigger it.

I'm curious though, why not put your "floating" o-ring on the rear portion of the piston?

And, are you casting urethane now?

[Novacastrian]

The size of the piston is 98mm

That's just shy of 4 inches, what ungodly beast is this component for?

Well it's simply for a multi purpose cannon, something that can shoot stuff up to 33.7mm, down to 12.7mm
The chamber is 304 stainless approx 200mm long, walls are around 2mm thick. Max piston travel will be 8.5mm
The major hassle is modifying certain details of the barrels (to make them efficent, i will have to alter their length in the chamber to adjust piston travel and sleeve them as to get rid of dead space) as the design involves putting a barrel "stub" into the chamber witch will be a piece of the largest dia barrel i will be using.
Should be good with the larger barrel up to ~300psi. Not that i plan on using it at that pressure- normal shop pressures should be enough.

Edit: Sorry Gippeto i missed your post, i have been casting poly for quite some time now. It's bloody awesome gear.
Different hardnesses, from soft as a pencil eraser to hard as nylon, the bumper is 40a duro (pencil eraser) and the sealing face is slighty softer than bone 90a duro (95 is hard as bone).
As for the hammer piston i decided to keep it simple

@JSR i don't think it will need ribs but i will be the first to fess up if proven otherwise! Thanks for calling it "Dainty" too Prick

[SpudBlaster15]

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[MrCrowley]

Well it's simply for a multi purpose cannon, something that can shoot stuff up to 33.7mm, down to 12.7mm

You must be mistaken, golf balls are 44.5mm in diameter

[Novacastrian]

Well it's simply for a multi purpose cannon, something that can shoot stuff up to 33.7mm, down to 12.7mm

You must be mistaken, golf balls are 44.5mm in diameter

JSR has a fetish for Epoxy, I have a fetish with smaller calibers 8)
It is much easier for me to get away with smaller stuff here. I could make a golf ball barrel to fit but i would be relying on 33.7mm porting

Edit: Gippeto i misunderstood your previous comment about my "floating" o'ring. I was just about to ask why it would be better, until i realised that it would be because i would lower the pilot volume, however when the piston hits the bumper it should seal, negating that fact somewhat. Thanx for opening my eyes

[jackssmirkingrevenge]

Well it's simply for a multi purpose cannon, something that can shoot stuff up to 33.7mm, down to 12.7mm

Ooh, now that's something to look forward to The 40mm PVC pipe I use for chambers has the same inner diamter, interesting.

As for the hammer piston i decided to keep it simple

I think he meant having the o-ring as check valve rather than incorporating a hammer piston.

Thanks for calling it "Dainty" too

That's exactly what it is, ya big poofter what's the final colour scheme going to be?

[Novacastrian]

Thanks for calling it "Dainty" too

That's exactly what it is, ya big poofter what's the final colour scheme going to be?

You made my afternoon with that comment Biatch

[jackssmirkingrevenge]

I'm sure you'll counter it with a host of very manly damage pictures eventually, do we have an estimated time of completion for this one?

The chamber is 304 stainless approx 200mm long

One thing, why so short? Since you're using shop pressures, I'd go for at least half a metre of chamber length.

[Novacastrian]

As would i, however i use the "scraps" The time of completion for this will be by the end of the week, fingers crossed, about another 3 hours.

Keep in mind that my total expenditure over all of my cannons and ammo would not have exceeded $150Aus

Edit: Just realised that if i take into account the fact that i am on the clock at work i have probably "earned" about $2000 dollars making my cannons.
Hope PCGuy doesn't see this

[MrCrowley]

Keep in mind that my total expenditure over all of my cannons and ammo would not have exceeded $150Aus

Times that by 15

Bloody addictive and bloody expensive.

[jackssmirkingrevenge]

Bloody addictive and bloody expensive.

I spend a lot on airguns, but not spudguns. The amount you save by casting your own fittings is substantial, for example why purchase a pressure-rated endcap when you can make your own with a cardboard disk and a pouring of epoxy that costs you less than $1?

[MrCrowley]

Bloody addictive and bloody expensive.

I spend a lot on airguns, but not spudguns. The amount you save by casting your own fittings is substantial, for example why purchase a pressure-rated endcap when you can make your own with a cardboard disk and a pouring of epoxy that costs you less than $1?

Because I like pissing $13.27NZD up the wall everytime my holesaw comes a bit loose and makes a hole too big in the end cap.