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Short question topic

A place to ask general spud cannon related questions.
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Re: Short question topic

Unread postAuthor: hectmarr » Fri Aug 03, 2018 2:36 pm

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Re: Short question topic

Unread postAuthor: farcticox1 » Fri Aug 03, 2018 7:19 pm

hectmarr wrote:Does anyone know what this red knob is for?


That's what I used for the trigger :shock:

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Re: Short question topic

Unread postAuthor: hectmarr » Sat Aug 04, 2018 7:33 am

A beautiful trigger and I unknowingly ... :wink:
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Last edited by hectmarr on Sat Aug 04, 2018 7:51 pm, edited 1 time in total.
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Re: Short question topic

Unread postAuthor: farcticox1 » Sat Aug 04, 2018 3:45 pm

Makes for an easy trigger :idea:
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Re: Short question topic

Unread postAuthor: hectmarr » Sat Aug 04, 2018 8:04 pm

farcticox1 wrote:Makes for an easy trigger :idea:

I was improvising this little semiautomatic thing to shoot 6mm plastic balls, I work a couple of hours. That's why it was the question. I operated the shot with the solenoid, but now that I know what the orange button is for, I shot from there, as you explain.
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Re: Short question topic

Unread postAuthor: hectmarr » Thu Aug 23, 2018 10:09 am

What standard should a steel tube with an inner diameter and about 1.5 mm - 2 mm in wall thickness, manufactured for high pressure?
Can it be ASTM 312 SCH 5S?
I mean what kind of steel tube do you use?
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Mon Aug 27, 2018 4:40 am

Are you trying to calculate the burst pressure?

This is a good calculator to use, of course you need to know the grade of steel used but you can at least make an approximate determination.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

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Re: Short question topic

Unread postAuthor: hectmarr » Mon Aug 27, 2018 8:59 am

jackssmirkingrevenge wrote:Are you trying to calculate the burst pressure?

This is a good calculator to use, of course you need to know the grade of steel used but you can at least make an approximate determination.

Yes, just that. I have to buy a steel tube to build some more pressure. The calculator is very useful. Thanks Jack :)
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Re: Short question topic

Unread postAuthor: hectmarr » Tue Aug 28, 2018 4:50 pm

I found this table ... It seemed useful to me and that is why I leave it to everyone's consideration. I put colors to those that interest me, only this.
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Tue Aug 28, 2018 5:54 pm

The obligatory question is what kind of mix numbers will you be burning?
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: hectmarr » Tue Aug 28, 2018 7:51 pm

In my case, low level of mixing pressure, how much 10X, although I have projected 8X for the new camera that I will build. It would be about 1100 psi, 80 bar, as pressure peak approximately, surely less, It would be within the working pressure that tolerates a seamless tube sch 5 of 3/4 "and 1.6 mm of wall.The sch 40 tolerates much more, and is easier to get from these sides :roll:
The problem is that the tubes I am using have a thickness of 0.8 mm and have laminated and polished seam ... I feel uncomfortable when passing 6X, and it would be a serious flaw with the weapon so close to my face. It's not worth risking.
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Re: Short question topic

Unread postAuthor: wyz2285 » Tue Nov 27, 2018 6:00 pm

Anybody knows how a gas ram/ spring works? I tried to make a gas ram powered bolt action but no matter what I do it leaks over time, I made sure the surfaces are smooth, free float and right size o-ring (two of them even!) and it just leaks...
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: farcticox1 » Wed Nov 28, 2018 5:26 am

A bit like a gas ram that holds up a car tail gate.

Theoben Gas Ram.jpg
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Re: Short question topic

Unread postAuthor: wyz2285 » Wed Nov 28, 2018 5:30 am

I know, but how does the inside looks like?
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Wed Nov 28, 2018 9:03 am

farcticox1 wrote:A bit like a gas ram that holds up a car tail gate.


That's more or less what it is, here is the relevant patent.

Personally, I think such devices are of limited relevance to the average spudder because of the need to retain large amounts of stored mechanical energy on a single point, in a manner similar to a crossbow. It can be done, but it's easier and more practical to store that energy as pressurized gas that is released by a valve. If you look at commercial airguns, there is a fairly low upper limit that such configurations can achieve in terms of energy in the 30 ft lbs range, while precharged pneumatics can be an order of magnitude more powerful.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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