Soon to be built 4inch housing piston, 3 inch porting

[SpudUke5]

I already posted this in one of my other topics, but since it also pertains to this, i am going to post it here also.

Well i tried my new coaxial today and it worked but i had a major leak in the front where my barrel sleeves through the bushing. It always seems that i get a leak whenever i sleeve the barrel through the bushing and this is a major problem for me that must be fixed.

How do you guys ensure that it doesnt leak through the bushing (female part)? Epoxy?

Since i am soo going to make my 4 inch piston, 3 inch porting cannon, i cannot manage to make mistakes and get leaks like this.

The problem may lie in when i am dremeling, or in my case using a drill with a dremel tool to sand away at the bump that blocks my barrel from going through the bushing. I may sometimes drill at the smooth part and it may cause there to be an uneven area that air may leak through.

I may have a solution. That would be to apply epoxy in the female part along with the primer and cement, so that it glues and the epoxy fills in the grooves.

So what do you guys think? Tell me what you do to sleeve a barrel down a bushing.

[frogy]

I'm just going by the parts I thought he was going to use... I suggested that he not step it down. Even though I think he already had that it mind

If a tee is 3" ported... That normally means 3" everywhere, except for the piston in some cases...

Your post doesn't really make sense though... Why would you size a pipe down to 3" with a bushing, just to size it back up with another?


and for your question Crotchus, I think epoxy is unnecessary if you do it correctly Try to just dremel out the bump only, and then finely dremel the rest of the bushing just a scrape... If you don't think the fitting will slide through, possibly try fitting it while wet before grinding more away... The fit through the bushing should be fairly tight, but still workable, without glue...

Remember to dry off the pipe and fitting before gluing

Epoxy should fix your coaxial though, I don't recommend on planning to mess up a weld so you can use epoxy

[SpudUke5]

What i mean by 3 inch porting is the barrel, which i heard from someone here that 3 inch porting is the barrel size.

Yea i guess i just cant mess up. I have alot more time to finish this cannon so i am going to carefully dremel this as best as i can, the when i am gluing, i will use the glue as a lubricant to slide it down the barrel, but im not going to prime inside of the female part of the bushing because primer only makes it worse when trying to slide it down. The same thing happened with this coaxial i just made.

Ill try your method of wetting it first and then drying it. That friction may cause a little wear on the inside of the female part of the bushing but it will only help me.

So frogy ne more projects? Large or small scale?

[DYI]

The porting of a barrel sealer is generally considered as the part in its main chamber----> barrel flow that has the least flow. In most cases, this is the barrel port. The porting doesn't include the pilot, which the main firing flow doesn't pass through.

[frogy]

I'm planning on making a fancy advanced combustion... A pneumatic airsoft sniper... A paintball trip mine-type grenade... Countless ideas I will most likely carry out...

Expect many guns at our shootout I'm trashing a few old ABS guns, even though they are perfectly safe, they're just too ugly for me

I would also like to make a semi-auto golfball gun... I need some 1.5" SDR 21/26

[SpudUke5]

Well we can always trash those old ABS guns at our shootout with our new guns Now wont that be fun

You got alot of ideas but how many of those cannons can you build before our shootout?

i think that you should that build the advanced combustion or the sniper before the we have our shootout. I will provide the firepower with this cannon so you dont have to bring a golfball gun.

but all of those ideas sound interesting ne way.

[frogy]

I'll definitely be making an advanced combustion... As of now I have plenty of 3" pipe to make it, but I'm thinking about 4" pipe, or a clear chamber...

$30 for 4' of 2" that's only rated for 140 psi or so isn't very interesting though

I'm probably going to go with a 3" to 2" or 4" to 2" gun

Why do so many people use clean outs if Male\Threaded Caps are safer? and much easier to not get hair spray or something sticky onto the threads.

I'm not that interested in combustion at all other than mini's though... So I may just trash the large combustion idea and go with a hybrid or another pneumatic

I do have a coaxial type sniper on the way... but currently I messed it up

The next attempt, probably tonight, will be a 1.5" to 1/2" or 2" to 3/4" with a 3/4" female threading...

[SpudUke5]

That sucks, you messed up your sniper O well.

I dont really like combustions, due to the failure they have, in my experience, in the winter, but i still have summer to wait for so that may be interesting. I just built one just to know if i could.

Pneumatics are interest. I say you go for a hybrid, just so ou can bring it so i can see it shoot supersonic, if we can get that, which is fesable.

Well i hope yout attempt is a succes

[frogy]

I put together a few more valves\guns this weekend through today... I'll post the images after I make sure they're working... Hopefully with a small test shoot if I can... Supposed to be reaching subzero temperatures soon aren't we though?

I have a 2" to 3/4" coaxial (PB\airsoft), now completely finish (-paint ) 2" BST, and a 1" to 1/2" BST for piloting the 2", or small cannon...

[SpudUke5]

Well i recieved my parts today and man are they big. They are definatley pressure rated so i have no worries on that.

I ordered the parts from sprinkler.com, the same place schmanmann did for his swat cannon.

I am soon going to start my building after i get homework out of the way and soon enough i will have a cannon built.

If you want pics, just tell me.

[MaxuS the 2nd]

Go on, do us a pic of all your bits and bobs.

[SpudUke5]

Well here is my piston that i have made. Tell me what you think.

[frogy]

What kind of foam is that?

The sealing face loops a little floppy, possibly try using a thicker metal so it doesn't bend and then bolt on a 2.5" washer so the sealing face stays straight...

I've never used an end cap for a piston before, so I'm probably a very good person to take advice from...

I think the foam is a great idea to fill dead space and use as a bumper... I definitely need to add some to mine... I may borrow some Polyurethane foam from my school it's just a two part thing...

[SpudUke5]

thats foam from a water football

The reason why the sealing face is floppy is because i have it screwed on well so that it wont come off and because its on tight i kindof lifts the face up a little. The cap fits tight and perfectly in 4 inch pipe.

I will try to get a 2.5 inch washer from home depot. All i need the metal is support so i should be fine for holding it up, and also i dont know if homedepot sells thicker sheets of metal and i also dont know if my metal scissors can cut thicker. I also pushed my piston against my the seal and the metal seems to hold up well because the pressure is distributed among the seat's lip.

[frogy]

Ah ha Tin snips aren't good for cutting sheet metal and keeping it flat

Do you have a jig saw, a band saw, or a scroll saw to cut the sheet metal on so it stays flat?

If you can find a washer that is smaller than 4" and bigger than 3", and one that is smaller than 3", but bigger than 2", you can place the rubber between the say, 2.5" and 3.5" washers, which will keep the rubber nearly perfectly straight and strong...

I'd just make the washers out of sheet metal, but I have a scroll saw and jig saw to cut metal on