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Posted: Sun Jun 22, 2008 7:10 pm
by Lentamentalisk
epoxy=superglue
epoxy is a super glue.

as for the fueling/ignition issue, don't listen to spudfarm. just put your fuel in first, and then turn on the air. The air will be flowing in much faster (and way more of it) and will create a ton of turbulence, thus mixing your fuel. If there is any less fuel near the spark plug, that will change quickly, as the air will be swirling around, and will also diffuse fairly quickly.

edit: Oh ya, also, DDT is unlikely if you use and air/propane mix, but could be getting dangerous with an oxy/propane mix because of your (I am assuming) skinny, long barrel.

Posted: Sun Jun 22, 2008 7:14 pm
by SpudFarm
it is just a guess from my side..

it is a pretty darn fast "bottle neck" and i was thinking it took a while before it got there

Posted: Sun Jun 22, 2008 7:48 pm
by DYI
Unless you actually go to all the trouble of purging the chamber of any inert gases before you fuel, I can't see detonation being a problem in that chamber with oxy/propane at the mixes you're talking about. Even at 20x, there'd still be about 13% nitrogen left. It seems as though even a small percentage of buffer gas can make the crucial difference.

I say that because my ME20H-41 has the same diameter chamber, almost 3 times as long, and has fired more than 20 oxy/fuel mixes, with two at 20x, and most at 10 or 12x. If it had detonated a significant amount of fuel on a few of those shots, I'd have noticed it by now.

I'm not saying to stand beside it when you fire it, just that it probably will hold together fine with oxy/propane. Just stay away from acetylene.

Posted: Sun Jun 22, 2008 9:11 pm
by brplatz
So the epoxied barb/sparkplug will work ok. And it will mix like i thought with diffusion and all. I heard about purging the chamber and such but isnt that only neccesary with oxy/propane or oxy/MAPP mixs? For now its just Air/Propane and will be that for a while!

Acetalyne = Boom
Sddds13 has some nice experience with that :D

Posted: Sun Jun 22, 2008 9:33 pm
by sddds13
I love my micro acetalyne cannon. Nothing like a tennis ball catching fire and flying 250+ yards.

Posted: Sun Jun 22, 2008 10:46 pm
by brplatz
yes that is quite fun! flaming tennis balls + desert is bad though

Posted: Mon Jun 23, 2008 7:26 pm
by sddds13
UPDATE: Ignition Coil will be installed thursday. Wiring is complete (except coil) and damage pics should be up on thursday or friday. Video and pictures will soon follow. Any ideas of what you would like to see get destroyed please tell us.

Posted: Mon Jun 23, 2008 7:44 pm
by SpudFarm
sddds13 wrote:. Any ideas of what you would like to see get destroyed please tell us.
what about that extremly mad making avatar?

or a two by four

Posted: Mon Jun 23, 2008 8:19 pm
by brplatz
Because sddds13 thought it was hilarious,

those 330v capacitors give a NASTY shock when you touch them fully charged! i really tossed that camera flash! Just for everyone else be careful cause i nearly s@#$ my pants :D

Posted: Mon Jun 23, 2008 8:39 pm
by sddds13
If you want real fun break the capacitors off the board and then charge them. Then throw them at someone. LOL there reaction will be to catch it and BAM you shock them crazy good. Altho they may kill you after. Buy a small capacitor from radioshack.

Posted: Mon Jun 23, 2008 8:43 pm
by SpudFarm
i passed out from a camera cap dumped into a ignition coil (twice)

Posted: Mon Jun 23, 2008 9:36 pm
by brplatz
now that sounds really bad. i wear my pvc insulated gloves from now on!

Posted: Mon Jun 23, 2008 9:55 pm
by sddds13
spudfarm wrote:i passed out from a camera cap dumped into a ignition coil (twice)
That is why you never want to build cannons naked. lol that would be a bad sight for anyone.

Especialy if you had many 3/4 holes cut into potatos. lol they may think something is going on.

Posted: Mon Jun 23, 2008 10:14 pm
by daxspudder
During maintenance on my sub(marine not woofer), we often take charged capacitors and toss them to each other, it really is a lot of fun... if your the one throwing it...

Posted: Mon Jun 23, 2008 10:56 pm
by THUNDERLORD
Those camera flash caps are no joke.
One got me one time while ripping the plastic cameras apart, my jaw went MMMmRRR!! Then I kind of laughed cause it was inevitable.

I was thinking of making a flashy blinding light(s) contraption to add to the muzzle end of a home defence type something for night time use.

Or add a red lense for simulated muzzle flash for some cool toy gun.

Back on topic, nice Hybrid, hope to see finished pics/info. 8)