O-rings? Are they feasible for the shallow pocketed?

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Xerxys
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Sat Jul 12, 2008 12:55 pm

I hate asking for help like this because there is probably is already a topic on it and it annoys me when other people do it. Moving on.

I need to make some O-ring grooves for a pneumatic, well, device. It's not actually a cannon but you guys are experts and I'm a member here so I decided to ask

The problem is: I have a dremel, a drill and a small budget. Nothing more.

I am also a Brit.

If anyone knows how to make the grooves please tell me.

The device does launch ME so it almost could be partially in the right place.

P.S. Any guesses on what it is?

P.P.S (off-topic) 4th cannon (1.5" bore, 3" chamber, Dual solenoids, burgle like) almost finished.
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kablooie
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Sat Jul 12, 2008 1:11 pm

The way I make O-ring grooves is to take a coupler, pipe, or another straight edged fitting that will fit closely over the the thing I want to put a groove in and then go around the edge of it with a hacksaw, or a larger handsaw for a bigger groove. This works pretty well, I made a pneumatic ram (1/4") for my current project with it, and it seals very well, but not perfectly. It takes a whole lot of patience, and you have to make sure to be careful and even, but it's worth a shot.

If you are looking for perfection, it's gonna take a lathe, unless you are extremely patient, coordinated, and lucky.
Xerxys
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Sat Jul 12, 2008 1:16 pm

I was planning to use a couple rings anyway for the seal bit i need to make the grooves in a cap so I can't use a coupler
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pizlo
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Sat Jul 12, 2008 1:18 pm

I do em by eye with a dremel.
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kablooie
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Sat Jul 12, 2008 1:21 pm

You could use any straight edged round hollow thing to do it. Be creative, start searching for things that might work, other pipes, fittings, jars, whatever. I am always searching the recycling for things that would work as pistons and ammo, and I suggest, if all else fails, looking there to find your coupler substitute.

Edit: Pizlo, does that work for you? What are the seals like?
Xerxys
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Sat Jul 12, 2008 1:49 pm

Thanks, I suppose I'll do 'em like that then. The seal is already really tight without the O-rings so I should be O.K. The seal is (and remember this is British pipe) between a 1" end cap and 1.5 " pipe. It is a Perfect fit. Easily tight enough to use a fitting

Oh, and it is for an air-pressure (like the vurtego) pogo-stick
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Coodude26
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Sat Jul 12, 2008 2:39 pm

Yea, here in the US at least 3" endcaps fir really well into 4" pipe.
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frankrede
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Sat Jul 12, 2008 3:22 pm

Coodude26 wrote:Yea, here in the US at least 3" endcaps fir really well into 4" pipe.
No f*cking way.
Seriously, that has NOTHING to do with O-rings.
Current project: Afghanistan deployment
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pizlo
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Sat Jul 12, 2008 3:30 pm

I used that method for an impromptu water shooter thingy, and I'd say it was about 95 percent water tight. So for most spugdun situations I would have to do better.
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jonnyboy
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Sat Jul 12, 2008 4:03 pm

frankrede wrote:
Coodude26 wrote:Yea, here in the US at least 3" endcaps fir really well into 4" pipe.
No f*cking way.
Seriously, that has NOTHING to do with O-rings.
Yes it does, read the topic. He needs a straight cut...
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frankrede
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Sat Jul 12, 2008 10:27 pm

jonnyboy wrote:
frankrede wrote:
Coodude26 wrote:Yea, here in the US at least 3" endcaps fir really well into 4" pipe.
No f*cking way.
Seriously, that has NOTHING to do with O-rings.
Yes it does, read the topic. He needs a straight cut...
No it doesn't.
Cooldude isn't talking about a straight cut.
Current project: Afghanistan deployment
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ammosmoke
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Sat Jul 12, 2008 10:54 pm

It is launching you? Are you sure sure that you want to make something like that using such a ghetto approach? Are you sure the barrel won't just collapse from the weight of you being in it?
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Coodude26
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Sat Jul 12, 2008 11:42 pm

Xerxys wrote:The seal is (and remember this is British pipe) between a 1" end cap and 1.5 " pipe. It is a Perfect fit. Easily tight enough to use a fitting
That's what I was talking about.
clide
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Sat Jul 12, 2008 11:57 pm

Xerxys wrote:The device does launch ME so it almost could be partially in the right place.

P.S. Any guesses on what it is?
Pneumatic pogo stick?
Edit: Oops I just now saw that you already said what it was.


The method I was fond of before I got my lathe was layering different round objects. What I would do is find something that was the diameter that the bottom of the groove would need to be and then find something that would fit around that to hold the o-ring in place.

For example for 2" o-rings I would use some 1.25" pipe or a 1.25" plug and I would put sections of 1.25" coupler around it with a gap to make a groove. Then I would use a 3/16" o-rings around it. Fine tuning could be done with Teflon tape to make the fit tighter or careful use of a file to make the groove a little deeper.
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SpudMonster
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Sun Jul 13, 2008 1:01 am

Coodude26 wrote:
Xerxys wrote:The seal is (and remember this is British pipe) between a 1" end cap and 1.5 " pipe. It is a Perfect fit. Easily tight enough to use a fitting
That's what I was talking about.
He's not in the U.S. so the 3" endcaps comment is off-topic anyway.
Stupid quote of the now:
joestue "The chamber is rated to 100 psi, it don't say that on the side, but the 2 inch stuff is rated to 300, so by analogy..."
"only the last two feet hear the end is black cellular core"
"I'm taking it to 300 psi"
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