mortar tube sizes/thickness

[Ralph]

Arthur, Multibreaks cannot be shot from anything but steel. Show me close proximity video of a successful (out of the barrel and in the sky) 4" or larger 4 break or more shell fired from anything but steel and I will send you 1000 cap plugs for free, shipping included to the UK.

 

 

Do really long single break cans count ?

[Mumbles]

http://www.pyrobin.c...0may%202010.wmv

 

The shell at 2:15 was fired from fiberglass. I'll take my caps any time jk

 

I do agree. I never fire anything more than two breaks from anything but steel. Well, I've done four break 3" and three break 4" shells from other mortars. Fiberglass is actually better than HDPE for multibreaks due to the one piece construction. I have a friend that swears by the stuff. Anything under 10lbs he'll shoot from fiberglass, sending up 2 and 3 break 5" shells routinely.

 

I really wouldn't go out looking for steel for guns and try to make one yourself. Even if you think you're an excellent welder, it's best to at least have someone who's done it before make the first one. As has already been mentioned, cast iron is a big no-no. I believe Shimizu recommended steel with a seam. The theory was that you can point the seam away from yourself, and it will (in theory) rupture that way should it decide to give. I believe all the club steel guns are seamless.

 

On the topic of multi-break shells, I hope you're comfortable making lots of flash. Bottom shots make multibreak shells safer and more likely to survive the lift.

[Ventsi]

Thanks fellas. I'll go out to the metal yard sometime this week and talk to the guys there about what I need. And yes, I'll likely have my shop teacher weld it for me, real nice guy, we go skim-boarding sometimes. And Mumbles, I already have them built and there are no bottom shots, I just put a big piece of solid cardboard on the bottom, along with some corrugated cardboard to act as somewhat of a shock absorber.