DoomLabs: Gandalf's Staff

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I built a 12 gram based Gandalf's Staff Cannon with a sliding breech for the MXS Two Towers game at EMR. It shoots the mini-nerfs. While discussing the concept with Mother (of MXS) she accepted the concept for refinement and contingent upon me considering actually taking the Gandalf role at that game. I accepted the role and built the staff (I would have built it anyway). The staff, along with the Devastator-III and expecially the tremendous support of my fellow members of Dead By Dawn and my raucaus and aggressive portrayal of Ganfalf won me an MVP for that game.

I don't have many pictures developed or scanned yet so stay tuned. Also note that the performance of the mini-nerfs is very marginal as it is so don't be in any hurry to build one.

Sliding Breech
Fires mini-nerfs
400 PSI globe lever valve
1" Copper chamber
Chamber divider for 2 shots per 12 gram
Two piece take down
12 gram CO2

Dr Doom as Gandalf with Cannon Staff

Note the 12 gram based Gandalf's Staff Cannon with the sliding breech. It shoots the mini-nerfs. Surprisingly the vest came clean!

Design Concepts

The goal was a staff that was also a cannon. 2" PVC is very workable - but very unwieldy as a tall staff. I had previously discovered that the 1.25" thinwall PVC provides a perfect fit for mini-nerfs. And it's a reasonable diameter for a staff. And I'd been wanting to combine the two for quite a while.

Constant air was desired - but not practical for the diameter of the PVC pipe. As it turns out, 12 gram CO2 cartridges turned out to be a good match.

A whistle valve was strongly desired (squeeze action lever valve) and I had only recently found out what these were called and where to obtain them.

Given the low performance of the mini-nerfs, and with some experimentation, I found I could asymmetrically split the chamber and get nearly similar performance from both shots (first shot is upper chamber only; second shot is with entire chamber).

I found that I could use the the mini-saw blade on my dremel (the spring steel one - NOT the sculpting disc) and split the PVC pipe (you can see the split line if you look) With splits and relief cuts I found I could hork and slide the pre-assembled cannon inside the lower sheath.

The sliding breech works well - but required a lot of sanding. The sleeve is a split piece of pipe and it really wanted to contract. With a bridge piece (and a useful interlock) and a lot of pipe sanding I got it to slide easily yet seal the air. Next time I'll boil the sections to attempt to relieve the internal stresses.

The mini-nerfs are too light to carry very far. They are also finless and I found that the muzzle blast would tweak them off line and they'd go in all directions. Indeed one was lucky to hit a car 10 feet away they were so screwy (I was ready to drive over the assembly at that point). During the game I found I could stabilize them somewhat by poking a 6" piece of flagging tape up the bottom end. They still don't go very far, but they fly straight. (Ok, they wiggle like a shark swimming).

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