12/12/06 Big Update - The Taternator II Aluminum Spud Gun

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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mark.f
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Fri Dec 22, 2006 9:56 am

I've got a hypothetical question for ye:

Let's say, <I>if</I> I wanted to build something similar, what's your thoughts on aluminum tube 3" ID, 3.5" OD, (with standard tolerances taken into account), blocked off on both ends with 1/4" aluminum plate bolted together with 3/4"-10 threaded rod and sealed off with Buna-N gaskets? Also, 2" female SCH-80 steel threaded adapters would be welded into place, (with supports from a coupling and some aluminum I-beam on the inside), on both sides to attach the barrel on the front and to vent on the back? That's the simplest way I can think to pull of an aluminum gun. My calculations say that this pipe, (with the aluminum 35,000 PSI yield tensile strength), would be safe to use up to about 760 PSI. What would you say, necessarily, that your gun would be fairly rated to?

Also, if you're looking to add some more stuff to this, I know where you can get a pneumatic cylinder, (double acting), operated elevation system for under 100 bucks. That'd be neat, eh?
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Dumbascii
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Fri Dec 22, 2006 5:01 pm

markfh11q wrote:I've got a hypothetical question for ye:

Let's say, <I>if</I> I wanted to build something similar, what's your thoughts on aluminum tube 3" ID, 3.5" OD, (with standard tolerances taken into account), blocked off on both ends with 1/4" aluminum plate bolted together with 3/4"-10 threaded rod . . .
Also, if you're looking to add some more stuff to this, I know where you can get a pneumatic cylinder, (double acting), operated elevation system for under 100 bucks. That'd be neat, eh?
I'd worry about the 1/4" plates deforming into a cup shape from the pressure. At 500 PSI, that plate would feel 3534 pounds transfered to the corners where the bolts are. Any perforations like for ignition, fuel, venting etc... would weaken the plates. That's why I used 2" thick aluminum block for the manifolds. 3/4-10 rods have such coarse threads you'd have a hard time getting uniform torque. I'm using 3/8-16 rods tightened to 100 inch-pounds and scary 2X oxy/MAPP mixes with no problem (except spud vaporizing).

You might do with a steel chamber welded (professionally) onto 1/2" end plates. Cheap, but would weigh a ton . . .

For elevation, a 12V electric drive on the 3/8-24 rod would work nicely. The fine threads take forever to drastically change the elevation. :(
codz30
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Mon Oct 08, 2007 7:01 am

HOLY SHORTS! that thing is only mean mutherf**ker! I dont want to be in that things way!
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wangpushups
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Tue Oct 09, 2007 3:16 am

Holy shit what a beast.
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Redcoat
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Tue Oct 09, 2007 5:17 am

That is one wicked-arse gun. I love the stand for it, Looks like it's come straight from a park swing. What kind of range do you get out of it?

A video would be awesome! :Headbang:

Happy Spuddin'
Poo.
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