You do realize black "iron" is steel pipe with a black finish, right? "STANDARD GALVANIZED STEEL PIPE # A-53-A Schedule 40 # Steam to 600 PSI, # Water, air, oil to 720 PSI # -20 to 400 Deg F " 720 PSI. A little bit higher than 150 :) Seamless pipe has a MUCH higher pressure rating. 1" Pipe that has...

boom_o_matic_2.0 wrote:well I guess I'll try that one site jook suggested

If you have a Tractor Supply company nearby, they sell it. Just make sure to ask them if you don't see it, they sometimes store it in back. 10ft for $8.

You do realize black "iron" is steel pipe with a black finish, right? "STANDARD GALVANIZED STEEL PIPE # A-53-A Schedule 40 # Steam to 600 PSI, # Water, air, oil to 720 PSI # -20 to 400 Deg F " 720 PSI. A little bit higher than 150 :) Seamless pipe has a MUCH higher pressure rating. 1" Pipe that has...

I wouldn't go above 100PSI. I think black iron is rated to 150PSI of steam.


What you are looking for is a schrader valve.

Hollowing the piston is fine, but you should seal off the hollow portion, or you will be increasing piloted volume. It has that "familiar" look. :) Sorry for all the questions everyone! I've made too many mistakes to redo anything else. :lol: Can I get away with using a pilot volume this large if I...

Thanks for letting me know about the DWV Tee, I was just following that instructables guide. :twisted: I reworked the piston and got it down to 1lb, 2oz. I think I can get it down even lower, I just need to borrow a 1" drill from work. http://img.photobucket.com/albums/v61/stampeder1/DSC_2282.jpg ht...

Well I can only calculate it if I know how long 350lbs of force would be acting on the piston, if it is a continuous pressure I can do that now though....350>80 so...yes it would Why does time matter. Wouldn't the force still hit a maximum of 350lbs(for example) no matter what, constant or split se...

Ok, I made a bumper out of an 5" 80lb compression spring.


But then I did some calculations and the surface area of the end of the piston is approx 7". This at 50psi equals 350lbs of force. I don't know how the weight of the piston itself affects things...


Will the spring pancake?

So, with one inch of travel, would ya'll think it's safe at say 50PSI? It couldn't gain that much momentum in one inch, could it? I need to find a good bumper in the mean time...

The only thing that worries me is if the tee breaks. All the fittings are glued to that and have a combined cost of $20.

1lb 11oz aluminum piston! :confused2: That's what I get for being an impulse buyer and not calculating the weight before hand... I left the grooves like that in the back for a giant spring to use as a bumper. Disregard the horrid finish of the middle of the piston, I was lazy and using a dull insert...

I am making a piston for a 2" valve(3" tee) using this as a guide: http://www.instructables.com/id/Colossal-Cannon%3a-Building-a-behemoth-piston-valved/? 3in pipe is not 3.00in. You would think this would be the case, but no. 3in pipe is really 2.946in pipe. Therefore, PVC rod that is 3.00in in diam...

Thanks guys! I don't think I want to go above 60 PSI, I don't want to take any extra risk on this thing blowing up. Would a longer chamber with a lower psi(50-60) be the same as a shorter chamber at a higher psi(80-100)? I don't plan on making this a cannon you can hold in your hands, I just want to...

I am building a golf ball cannon, and I currently have( not glued ): 10ft of 4 " pressure rated PVC 10ft of 1.5" SDR 21 PVC sleeved in 2" shd 80(barrel) And the appropriate fittings to make a 3" piston valve. What would be the ideal chamber/barrel length for both portability and power? I was thinkin...