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.

Features:

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

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).