Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 66 users online :: 4 registered, 0 hidden and 62 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Aluminium Tube Pressure Rated?

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Unread postAuthor: Gippeto » Mon Apr 28, 2008 11:21 pm

Hey Mitch. Might be a good find there. :)

Is this seamless tube?

Did some quick numbers. Used 2 mm for wall thickness, and 15 mm for od.

No way of knowing the alloy or heat treat I suppose, but as you cannot bend it, I don't believe it is annealed. :)

6061-0 (annealed) has a yield strength of 8000psi, which gives a burst pressure of 2138.75psi.

6061-T6 has a yield strength of 35000psi, giving a burst pressure of 9333.33psi.

200psi seems to be pretty conservative. :wink:
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2394
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Unread postAuthor: Mitchza89 » Mon Apr 28, 2008 11:50 pm

Yeah mate it's seamless tube, hence why I reckon it could be able to hold enough pressure to satisfy my hunger :D.

Thank you so much for the help with this mate. I reckon I'll be making the first aluminium piston gun on spudfiles pretty shortly. I'm gonna have the chamber as 25mm aluminium tube, all copper fittings, and a 20mm copper tube barrel. It's all gonna be nicely polished.

...Thats the plan anyway :D.

Cheers mate.
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: Gippeto » Tue Apr 29, 2008 9:15 am

Sounds good, I look forward to it! :)

20mm is going to have plenty of power! Watch the fence. :lol:
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2394
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Unread postAuthor: Mitchza89 » Tue Apr 29, 2008 9:16 pm

Hmm I'm a bit concerned... I got most of the parts for the gun. The 25mm aluminium tube is the slightest bit loose in the copper fitting. I'm gonna be using epoxy putty to keep it all together. Do ya reckon this very slight looseness will make a difference in how it's all going to bond?
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: Gippeto » Wed Apr 30, 2008 12:21 am

JSR is the epoxy "expert" , maybe pm him.

My suggestion would be to rough both sides of the joint with some 40 grit before you epoxy it together.

Do you have any info on the epoxy? Specifically the shear strength and/or tensile strength?

Might be able to make a better call with those numbers.
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2394
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Unread postAuthor: Mitchza89 » Wed Apr 30, 2008 12:39 am

Well the tensile strength of the epoxy putty I have is 3000psi. It's a metal epoxy so it might be alright. I'm still worried that the pipe wobbles a tad because the pipe has an OD, about a millimeter smaller then the ID of the copper elbow so it's not quite a tight fit.

Cheers mate.
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: Gippeto » Wed Apr 30, 2008 12:55 am

Ok.

Jb weld has a tensile strength of 3960psi, and a lap shear strength of 1040 psi.

Calculated for a 1" tube with a joint length of 1".

Surface area of joint= 3.14in2

Surface area x shear strength =3265.6 (we'll divide by 4 for safety)

= 816.4 pounds (maximum allowable force on joint)

Area of 1" tube =.785 in2

Max pressure = 816.4 pounds / .785 in2

Max pressure = (oddly enough!) 1040 psi

Should double check for the shear strength of the epoxy you will be using though.

What kind is it?
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2394
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Sponsored

Sponsor
 


Unread postAuthor: Mitchza89 » Wed Apr 30, 2008 1:06 am

:| Wow... You really know your stuff Gippedo. I'm very, very impressed...

I can't remember the name of it, but it's an automotive metal epoxy putty... I don't actually have it yet. I just know that I'll be getting it tomorrow :D. Ehh it should be fine mate. I won't kill myself because I won't be taking this gun high enough to start with.
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: dongfang » Mon May 05, 2008 4:00 pm

Hi

I just want to say - good luck with using aluminium! I just made a pump out of the same tube that you found.

Some time I will try get some aluminium welding rods, and see if I can weld it just with propane. If it works as easily as announced, that would be great for a hybrid..

Why don´t you also use aluminium for the barrel? It´s a much nicer material (IMO) for that than copper: It´s light, it doesn´t get bent as easily, it won´t corrode and look ugly, and no smelly fingers!

Regards
Soren
  • 0

User avatar
dongfang
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 448
Joined: Sun Aug 27, 2006 8:02 am
Location: Switzerland
Reputation: 0

Unread postAuthor: Mitchza89 » Mon May 05, 2008 7:12 pm

My thoughts exactly Soren :wink:. I really am generally surprised that more people have not gone into Aluminium tubing much at all. I reckon it's a great material to use. The only reason that I can think of, is that it's quite hard to bond together and find fittings for but if you have some decent epoxy or you know how and have the equipment to aluminium weld, then even better! :D

I saw your pump yesturday. It looks really well built. You should be able to get much more then 20 bar out of it though. I've taken my pump up to 350psi with no worries at all. I could have gone alot higher I think but my guage only goes up to 300psi and so I didn't want to risk breaking it.

Do you have any plans of making an all aluminium gun Soren?

Cheers mate,

Mitch.
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: dongfang » Tue May 06, 2008 4:39 am

Hi Mitch, thanks for the nice words.

I am sure my pump could take a lot of pressure, but I just made it for taking a gun up to 10-15 bar without breaking my wrists. With a piston area of about 3.33 sq cm, it will go up to about 15-20 bar with a reasonable effort / comfort. If I once need more, I'll make another, smaller bore pump! Of aluminium again...

Yes I have a plan of making an all-aluminium gun! Something like a burst disk free hybrid. Just a small scale experimental thing, to get a little experience with hybrids. My ultimate goal is the sonic GB :twisted: :twisted: :twisted:

Regards
Soren
  • 0

User avatar
dongfang
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 448
Joined: Sun Aug 27, 2006 8:02 am
Location: Switzerland
Reputation: 0

Unread postAuthor: Mitchza89 » Tue May 06, 2008 5:50 am

That's a great plan! It's going to be a beast of a gun :D. I only just realised that your pump has dimentions different to mine. I use 3/4'' copper as the cylinder. It would explain why I'm able to get to 400psi quite easily. The strong advantage of your pump, is your able to fill up your guns much, much quicker so it all depends on the pressure your after, and the size of your chamber. To get a decent marble gun up to 300 psi, I'll have to use a pump thats the same size as yours otherwise I'll be pumping all day...

When do you think you'll have this Aluminium weapon of mass destuction all writen up and designed? :D
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: dongfang » Tue May 06, 2008 7:22 am

Hi Mitch,

What is the exact (actual not nominal :wink: ) ID of your pump cylinder?

Yeah I'm already looking around for parts for one more pump. Maybe with a 16 mm (OD) cylinder. Just for some materials strength tests that I want to make, and publish here.

The aluimium gun is just in the planning stage right now. I have a few other things ahead in the queue. BUT in the lunch break today I could not resist going to the hardware store, and look at propane torches and aluminium welding (soldering) rods. They have it all!

Regards
Soren
  • 0

User avatar
dongfang
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 448
Joined: Sun Aug 27, 2006 8:02 am
Location: Switzerland
Reputation: 0

Unread postAuthor: Mitchza89 » Tue May 06, 2008 6:07 pm

I honestly couldn't tell you off the top of my head. ID is probably 21 or so mm and the ID would be about 18mm. These numbers are just total estimates.

Ahh I've got the same problem. I'll get bored so I'll duck to the hardware. I'll be poor as hell but I'll still walk out with 40 bucks worth of parts, ending up more broke... :D
  • 0

Image
User avatar
Mitchza89
Brigadier General
Brigadier General
 
Posts: 1056
Joined: Tue Jan 09, 2007 12:05 am
Reputation: 0

Unread postAuthor: DYI » Tue May 06, 2008 7:51 pm

Contrary to the opinion on the first page of the thread, tubing is generally higher quality, and made to higher tolerances, than pipe. I have a .25" ID SS tube with walls only 0.03" thick, which is RATED to 2000psi.

Good luck on using the aluminum tube, it really is one of the best materials for spudgun construction.
  • 0

Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
DYI
Lieutenant General
Lieutenant General
 
Posts: 2861
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan
Country: Turks and Caicos Islands (tc)
Reputation: 9

PreviousNext

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'