SpudFiles

Starman, he's from New Zealand like me, it costs us about $12-$15NZD($10US-$13US) for a small container of primer or solvent.

I am glad to hear you are doing it properly! This might seem obvious, but if you plan on taking a piston out of the threaded fittings, be sure to have the piston come out of the female end, because in my experience, male fittings have had a smaller inner diameter than the pipe, which would create major issues with servicing the piston.

With the pvc glue, be sure to seal the can very well, otherwise it could turn into a useless jelly-like stuff that you will have to throw away and waste your money.

hehe. yea I love the stuff already. SOOO strong. Can I use any O ring that fits? I could also hot glue over the screws, that stuff seals good but is fairly brittle. My piston doesnt seem to last long, I couldnt find the neoprene you were talking about and the pencil case isnt exactly durable. I would like to find some neoprene though

microman171 wrote:hehe. yea I love the stuff already. SOOO strong. Can I use any firrint O ring? I could also hot glue over the screws, that stuff seals good but is fairly brittle. My piston doesnt seem to last long, I couldnt find the neoprene you were talking about and the pencil case isnt exactly durable. I would like to find some neoprene though

Hot glue doesn't seal sh|t

Well every single Mitre 10, Hammer Hardware or Bunnings store in NZ will have rubber gaskets, either in orange or black, or both. They a circular, usually in a small clear bag and are about 8cm in diameter with a small 2 or 3cm hole in the middle.

They are there, just ask.

I did. The only thing she had were clear plastic things or toilet washers. Or is the toilet washers what you were tlkaing about? Hot glue does!! It just doesnt work on anthing that moves a bit... for example a car tyre valve (not the screw in shrader type but the tubeless tyre type.)

EDIT -

With the pvc glue, be sure to seal the can very well, otherwise it could turn into a useless jelly-like stuff that you will have to throw away and waste your money.

Took your advice! In fact I just went out to the garage to tighten the lid. I would hate to waste it.

Hot glue doesn't seal leaks at 100psi, trust me. It could help seal threads, but it wont seal a leak from a bolt on a serviceable piston. You'll need JB-Weld or silicon.

Where did you go? My hammerhardware had them in a draw with other stuff like that.

As long as it's rubber and is not porus it will work. It doesn't have to be neoprene. You have to improvise in this hobby, think a bit for yourself.

Yeah I was going to improvise... But the toilet washers felt a little hard and I dont like to waste money. I went to mitre 10 Matamata. Okay I'll trust you with the hot glue. What about O rings? I have a big pile of them that fit my bolts.

They're like $2 man, just try 'em out. And they would be hard, compared to a pencil case. Shouldn't matter anyway.

I meant an o-ring to go around the piece of pipe the end cap is bolted too. You'll have to make a groove for it.

MrCrowley wrote:Starman, he's from New Zealand like me, it costs us about $12-$15NZD($10US-$13US) for a small container of primer or solvent.

Bring him in-line there....long, deep breathing....

I sometimes forget the cost variance of things over there. I can see how $2k could get shot quickly on this hobby in NZ.

I do love this hobby so I guess it is worth it. This weekend (or maybe tomorrow when I am walking home) I will try them out. I didnt actually ask the price so I just assumed that I might cost more. Remeber I am new to all of this. Previous cannons involved ball valves. After that it was a spring trigger ball valve. Ah, so I dont need the bolts to be sealed? As long as I push the cap on good I should be fine right... I mean they taper the fittings for a reason - so they are well sealed.

No, you need a new definition of 'well sealed'

Hot glue does not work, tapered fittings will not work either.

This is 100psi, 50kg of force per square inch (2.5cm).

Tapered fittings will not hold this by itself. You should do a lot more research into pressure before continuing, you obviously are lacking some sense in safety. Do you take physics at school?


You will still need the bolts, did I say otherwise? No.

I said you will need the o-ring on the piece of pipe the end cap is on, before the bolts. So when the air will be stopped by the o-ring first, and then the bolts clamping the end cap on behind the o-ring.

So you carve a groove into the pipe, but not so much it goes all the way through, you then stick the right size o-ring on (will need to be about 50mm in diameter) and then you drill holes for the bolts through the end cap and pipe, and you put teflon tape on the bolts to help them seal.


Just search, plenty of people have done this before. And you really should learn it yourself so we don't spoonfeed you, otherwise you lack a common sense of exactly what you are doing and you may miss important info.

Also learning this for yourself you will gain improvisation skills. I hope you realise nothing in this hobby has any sort of SOP (Standard Operating Procedure), I.E. you can make anything from anything, as long as it has the principles.

What I meant was... The cap WILL NOT be on on its own, the bolts will hold it on. BUT the taperd fitting should hold the pressure. The bolts stop the cap from flying off. By O rings I thought you meant that the bolts needed them. I understand it all now and thank you.

The taper wouldn't contain the pressure, otherwise you wouldn't be able to get it on the pipe with ease. But yeah an o-ring should do the trick.

I'd recommend just using threaded fittings, so much easier. Though they're about $13 each in 2". You may need rubber washers on the bolts too.

Okay thanks . I have a plan now! I will post pics in the next few days!

There has been a long delay on this project because I have got other things to spend money on. I am thinking of making a completly NEW piston. It need to fit in 2" pipe. I also need to find a new sealing face (I am out of pencil case and bike tube doesnt want to work for me).