Piston problem again

[nabu92]

Yeah, I fixed that earlier today. I really appreciate all the help though.

[SpudUke5]

Well while we are on the talk of pilot, pistons, etc. i am going to ask a question.

As you may have heard or not, i am building a 4 inch piston cannon and i am wondering if i can pilot it with a blowgun, keeping in mind that the pilot volume is at its lowest volume. Is this possible? If not, then will a 3/4 inch ball valve be fine?

[MrCrowley]

Probably not without O-rings, and yes. Though a 1" sprinkler would be better.

Except that one problem, you know... ah...um... JSR will explain

Or the problem Fat Pants from UKSGC once had. That can't be solved with epoxy either.

I seriously doubt that story, it's all hearsay and sounds like a joke to piss him off.

[Velocity]

Well while we are on the talk of pilot, pistons, etc. i am going to ask a question.

As you may have heard or not, i am building a 4 inch piston cannon and i am wondering if i can pilot it with a blowgun, keeping in mind that the pilot volume is at its lowest volume. Is this possible? If not, then will a 3/4 inch ball valve be fine?

A blowgun probably will not work without o-rings (as MrC pointed out). The ball valve should work fine. For best performance and ergonomics, get a small (3/4) QEV and hook the blowgun up to that.

[SpudUke5]

Ah thank you velocity, and might i say that your americannon (the 4 inch piston one) is beautiful, only of you had the room to shoot it

So you are the perfect person to talk to about this matter. I know that you used 2, 3 inch endcaps as a piston and then you said that you modified it.
Can you specifically tell me what you did to the 3 inch endcaps?

I am using one 3 inch end cap as my piston and my problem i encountered is that it is kindof hard to put the sealing face (innertube) on the rounded part because it creates an uneven surface, so how did you put on your sealing face.

I have an idea of a modified piston but im not sure if it would work. My idea is that i would take the 3 inch endcap and saw off the rounded part. Then i would fill it with expanding foam and then when dried i would bolt on the sealing face. Would that possibly work?

I will most likely pick up a 3/4 QEV from Mcmaster which is 40 minutes away from my house. I though about using a 3/4 inch QEV from your cannon actually. I also may replicate something similar to your universal fill-pilot system.

EDIT: Also Velocity, how did you attach the QEV to the plug? Did you drill a hole in the plug? With a 3/4 drill bit, or whatever is closest? Did you attach it with a brass threaded bushing?

[MrCrowley]

I think Velocity sanded down the end cap to make it fit, not sure, I just hear that's what you have to do.

To get rid of the round end cap face, just get a large metal washer/disk and bolt that onto the front with the sealing face.

[elitesniper]

Ah thank you velocity, and might i say that your americannon (the 4 inch piston one) is beautiful, only of you had the room to shoot it

So you are the perfect person to talk to about this matter. I know that you used 2, 3 inch endcaps as a piston and then you said that you modified it.
Can you specifically tell me what you did to the 3 inch endcaps?

I am using one 3 inch end cap as my piston and my problem i encountered is that it is kindof hard to put the sealing face (innertube) on the rounded part because it creates an uneven surface, so how did you put on your sealing face.

I have an idea of a modified piston but im not sure if it would work. My idea is that i would take the 3 inch endcap and saw off the rounded part. Then i would fill it with expanding foam and then when dried i would bolt on the sealing face. Would that possibly work?

I will most likely pick up a 3/4 QEV from Mcmaster which is 40 minutes away from my house. I though about using a 3/4 inch QEV from your cannon actually. I also may replicate something similar to your universal fill-pilot system.

hey the mcmaster ware house is near your house? so you live some where in LA california?

[SpudUke5]

To get rid of the round end cap face, just get a large metal washer/disk and bolt that onto the front with the sealing face.

But saw off the face first right?

@ elitesniper: No there is one is Aurora, Ohio which is close to Cleveland, Ohio which is were i live.

Also froggy picks up his stuff there too, but he lives in Akron, Ohio which is just about the same distance.

[elitesniper]

ah, is it a store or a giant ware house?

[SpudUke5]

Its a giant warehouse, so all i have to do is call them, then have them direct me to the one is Ohio, then i order through the phone, and then in 45 minutes i can pick it up.

[jackssmirkingrevenge]

Except that one problem, you know... ah...um... JSR will explain

There are many problems defined as that one problem, but I'm sure epoxy can be used to solve any one of them

[MrCrowley]

To get rid of the round end cap face, just get a large metal washer/disk and bolt that onto the front with the sealing face.

But saw off the face first right?

If you find a a metal disk ~3" in diameter.

But you really don't need to, just put the metal disk on the end cap and sealing face on top of the disk, that way the sealing face can't bend back and is supported by the metal disk.

Okay, this is really simple, listen carefully.

Grab end cap with hole in the back for the bolt.

Grab metal disk and sealing face, both with holes for the bolt.

Grab a small metal washer to stop sealing face getting sucked away.

Put washer on bolt, put sealing face on bolt, put metal disk on bolt, put bolt through the back of the end cap and tighten with nut on the other side.

That's it, now the metal disk will stop the sealing face from flexing back.

[SpudUke5]

Ok i think i got it now, but to ensure that i do understand, i am gonna reiterate im my own words.

So do all of what you said but not on the round side, but the open face where the 3 inch pipe would connect if it was being used as a cap? Then therefore the round part of the cap would be used as a bumper? Unless i use a different configuration.

[MrCrowley]

Nope otherway round sorry

[SpudUke5]

Are you being sarcastic? if you arent, then i am not sure what you are talking about. Maybe a diagram? Im sorry that i dont understand. Its been a long day

But i did get a different idea from what you said, unless its your idea.

so im partially confused now

EDIT: Ahh nvm i got it, but dont you think that the metal may scratch the pipe?