SpudFiles

I mentioned it in another thread, but I'll give more details here...
It's a working gun but not a completed project, yet...

It's a 40.5"x .5" barrel, 23"x1" chambered coax, I have fired it at up to 180psi and was wondering what you guys think max safe o.p. would be( I do value your opinions)....

The piston is a 1"x13/16"x1.25" rubber stopper, large end towards barrel, button head 5mm bolt going thru the center with nylock nut on the pilot side(the bolt and nut are just to expand it slightly for a snug fit), and a coil spring to keep it seated when not pressurized(credit to jsr), the pilot valve is a scrader with a modified cap and a pushbutton for firing...

It will fire with less than 5 psi ...

This gun will be inserted into a walking cane blank, and I'll be makeing a handle for it that will allow hidden access for filling and firing...

I'll post pic's og the working gun later today, and hopefully this weekend will get the cane part pinished...

Cool idea,
I like the walking cane part

But the spring behind the piston, won't it release the air slower because of the fact that the spring must also be pushed back/ compressed (If thats the right word..? ) by the air in the chamber, or is that negligible?

If the spring would be powerful enough, would that make a cannon a semi-auto one ?

what type of copper is it made out of...

Carlman wrote:what type of copper is it made out of...

Type L... solder/thread adapter on pilot end, 1" to .5" reducer(solder/solder) on barrel end, brass 1"to.25" bushing for pilot, brass .25" close nipple to .25" tee, fill schrade on one leg, fire schrader on other....

Oooh concealed stuff. Sounds good.
However, isn't 1" a bit thick for a walking cane?

psycix wrote:Oooh concealed stuff. Sounds good.
However, isn't 1" a bit thick for a walking cane?

Not if your pimpin'...lol

I have fired it at up to 180psi and was wondering what you guys think max safe o.p. would be( I do value your opinions)....

According to the copper tube handbook, Type L, 1" drawn copper tube has a rated working pressure of 850psi, and an actual burst pressure (room temp) of 5115psi.

That leaves the solder to consider;

Having crunched the numbers for 50/50 lead/tin on a 3/4" joint, I won't bother to do it again. As long as you don't leave it pressured up, creep won't be a real issue, and it'll hold if properly done.

Brazing the joint will anneal the copper, and lower the working pressure.

I run my copper guns at 400psi with no problems. (3/4" is the largest diameter though.)

Gippeto wrote:

I have fired it at up to 180psi and was wondering what you guys think max safe o.p. would be( I do value your opinions)....

According to the copper tube handbook, Type L, 1" drawn copper tube has a rated working pressure of 850psi, and an actual burst pressure (room temp) of 5115psi.

That leaves the solder to consider;

Having crunched the numbers for 50/50 lead/tin on a 3/4" joint, I won't bother to do it again. As long as you don't leave it pressured up, creep won't be a real issue, and it'll hold if properly done.

Brazing the joint will anneal the copper, and lower the working pressure.

I run my copper guns at 400psi with no problems. (3/4" is the largest diameter though.)

I actually used "solder-it copper bearing paste, csp-41" a plumber friend turned me onto it, it's basically solder powder mixed into a paste with flux, initial melting point is low, but to remelt(for seperating connections) it takes the normal higher temps(which is great because your first joint won't melt while your making the second, like on the reducer of a coax), to look at the joints you wouldn't tell the differance between this and typical solder joint other than this looks like it fills much better, and is a lot "cleaner" looking, and supposedly, 5 times higher pressure rating...

my plumber friend said he'd used it on pipes and then pulled them until the pipe tore, and the joints didn't fail...

Anybody here tried it?

I've not tried to pull a soldered joint apart, but I did calculate the pressure required to cause a shear type failure of the soldered joint.

It was many times the burst pressure of the pipe, this with 50/50 lead/tin.(I use 95/5 tin/antimony which has ~5 times the rated working pressure.)

I'll stick with conventional paste and solder. When pressurizing the joint, knowing it's fully soldered gives me peace of mind.

so...pictures?

Velocity wrote:so...pictures?

Updated to add pics... look at top of thread...

Looks great I can't wait to see it with the wood. How do you plan on concealing the pilot/fill end? Making a handle around it could be tough.

And nice organizers...hopefully we'll get to see some damage with those ball bearings.

daberno123 wrote:Looks great I can't wait to see it with the wood. How do you plan on concealing the pilot/fill end? Making a handle around it could be tough.

And nice organizers...hopefully we'll get to see some damage with those ball bearings.

REAL Damage will have to wait until I get some hpa, it does great with light projectiles, but the bearings REALLY need 400+psi to do impressive damage...

the handle will make JSR proud, it'll be made out of epoxy, with a vented black rubber button cover over the button, and I'm thinking about making the fill side so that I can use 12g co2 with a screwin piercing adapter for full stealth mode... use the little grey sabots in the box in front and behind the bearing(they are really tight), and then, if the occasion arises to ventilate something, screw in the co2 cartridge to fill and push the button to fire... Slick, huh?

12g co2 will fill this chamber ONCE to 643psi or thereabouts... {edited to remove possible connotations} So , one good shot should be all thats needed..

jeepkahn wrote:

psycix wrote:Oooh concealed stuff. Sounds good.
However, isn't 1" a bit thick for a walking cane?

Not if your pimpin'...lol

10 points

Air canes are a lot more common than people realise.

Great creation you got there...but the ammo boxes are what makes this post really cool