| Author |
Message
|
| FordGtMan |
 Posted: 04/20/2008 0:27 AM Post subject: BB barrels |
 |
|
1st Lieutenant
Joined: 25 Oct 2007
Posts: 251
188.37 Spud Bux
|
| I know that you can use a arrow shaft as a bb barrel for .177 but i am making a coaxial and i need to get a barrel that will fit. As a person who has a bow and shoots, i know the arrow arent too thick. My friend has a bunch of broken aluminum arrow shafts that i can use, but i dont think that it can hold the 200-300+ psi i plan on making it into. Even though it will only need to be 3 1/2 inches long, will it still hold the pressure down on it or will the pressures cause warping or other crap to it? Unless there are any alternatives besides getting a bb gun and stripping it down, maybe there are other alternatives that will hold the pressure? |
|
| Back to top |
|
 |
|
|
|
| ajdevi92 |
| Posted: 04/20/2008 1:01 AM Post subject: |
|
|
Major
Joined: 23 Nov 2007
Posts: 356
401.00 Spud Bux
|
| im sure if you check the pressure ratings for that grade aluminium you should be fine, it should hold decent pressures . |
|
| Back to top |
|
|
| THUNDERLORD |
| Posted: 04/20/2008 1:03 AM Post subject: |
|
|
Loose Cannon
Joined: 28 Mar 2008
Posts: 707
1319.08 Spud Bux
|
The aluminum arrow shafts I have are maybe about .177 at the front which is threaded for the arrow point to attach but they're wider on the inside.
I'd say that if it's only .177 and only at 2-300 psi you could test it from a distance/behind something.
Worst that could happen would be if a piece of it shattered and hit you in the eye. So always wear eye protection.
Aluminum would make a poor barrel though because it's so soft that it will wear from friction. Also if it does rupture, it's soft but brittle at the same time.
It might just bulge first then go all at once. So that type of testing isn't very effective.
A lot of people are using brake line that fits BB size (4.5mm) bought for cheap at auto parts stores. That stuff is not very thick and I don't know if that would hold 300 psi or not but atleast it's steel.
I would suggest as an alternative maybe sleaving pipes together that each fit inside another pipe to give a bigger diameter.
You stated 3.5" length of barrel. maybe you could start with an old antenea tube and find a bigger diameter that fits into and so on.
Most hobby shops sell brass tubing and you could work it up to fit a steel(or brass which is probably better since the steel pipes are really a mild steel)1/8" or sometimes called 1/4" threaded pipe.
Another possibility since the barrel is only 3.5" would be to find the drill bit that length and diameter and drill into solid steel that would definately hold the pressure.
Not much is better than a rifled airgun barrel for .177.
I mean look at airguns even the pistol ones that liquid CO2 regulates while already in the barrel!!!
BTW I'm wodering what the heck you're building w/3.5" barrel? |
|
| Back to top |
|
|
| FordGtMan |
| Posted: 04/20/2008 1:58 AM Post subject: |
|
|
1st Lieutenant
Joined: 25 Oct 2007
Posts: 251
188.37 Spud Bux
|
Thanks for the suggestions. I am making a mini coax  , yet again...
I might try to look for brass tubing, but i don't know if i can get them secretly, as my parents are a bit unsupportive on the idea of high pressure guns... |
|
| Back to top |
|
|
| THUNDERLORD |
| Posted: 04/20/2008 2:23 AM Post subject: |
|
|
Loose Cannon
Joined: 28 Mar 2008
Posts: 707
1319.08 Spud Bux
|
After I replied I thought you must be making a mini.
So I wondered how helpful my reply would be(I was thinking bigger).
Maybe there's a way you could use one of the stronger epoxies around the barrel. I haven't used them much for higher pressure, except on the ammo itself.
I seriously doubt anything .177 will cause much damage if it ruptures at 2-300 psi.
Also with the brake line there should be a way to find out the pressure rating since it's used to hold hydraulic pressure to work brakes.
EDIT:Just remembered, A long time ago I had the Crosman revolver that looks like a .357mag.
I wanted a longer barrel so I unclipped the barrel and it slid out and I replaced it with a single 12" brass tube from a Hobby shop. It worked great and held that pressure fine.(had to fit it into a mcdonald's straw to get it to fit in the fake barrel shell part). |
|
| Back to top |
|
|
| OuchProgramme |
| Posted: 04/20/2008 12:01 PM Post subject: |
|
|
Major
Joined: 12 Jan 2008
Posts: 373
534.55 Spud Bux
|
K&S, -Where i get my piping from-, has a great selection
I believe JSR used the same brass piping from K&S to build his 400 PSI Pen Gun. |
|
| Back to top |
|
|
|
|
