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my buddy and i just slapped this cannon together today out of abs. we glued on the parts on using the abs glue, but i am not sure how short the barrel should be nor am i shure about what kind of ignition system i should be using. preferably nothing too complicated. im looking for any constructive criticism. thanks in advance

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Very basic cannon... hm for ignition you can go out and buy a piezo grill igniter and maybe making a simple spark strip for your chamber out of a length of pvc cut in half...
Or you could try your luck at making a camera ignition system....

Your barrel looks fine.. since your chamber is 3 in and your barrel is 2 inch that looks about right.. Other thinggs you could include would be a fan for more reliable and faster ignition and metered propane if you want maybe 1/2 more the power >:D ...

thanks for the tips. this is our first cannon which is why it is so basic. we didn't want to get to technical with what little know how we have. we pretty well guessed on what peaces we needed at rona. although i am frammilar with the camera ignition system i have no knowledge of its effectiveness. i have heard talk about fans on here but have no idea how they are incorporated into the system.

A chamber fan sits in the chamber, mixing the fuel/air. Otherwise a spark has to be in a perfect spot where there happens to be the right mix. I assume your chamber is 2.5 inches? CPU fans are common, but most of the ones I have seen would work best in a 3-4 inch chamber.

i beleive it is a 3 inch, although im not posotive, we had to grab these materials fifteen minutes before rona closed. also one other noobie question, how common is it for these things to astronomicly fail. because im not a fan of having things explode in my hands, and am wondering if there are some definite no no's when firing these. also what keeps the fans from being burnt from the side effects of combustion?

Yes... you run 2 wires threew it.. You know what the perfect sites you should read are www.advancedspuds.com <<<< everything you need to know AND www.burntlatke.com < also excellent

Soak up a much information from those sites as you can it will explain everything you need to know about combustiones
good luck

Nothing, asides from the fact that the flame front doesn't have very good duration. You can pass your hand quickly over a lit candle, but you can't leave it in the flame.

As far as good information goes Burnt latke is around 9001 times better than Boogieman's site..

I'm surprised noone really mentioned fuel metering, that with a chamber fan will give some of the largest improvements.

Well.. Fueled meter in abs pipe... is doable but I wouldnt want my gun blowing up.. well in the case for abs.. tearing up...

And yes I know that burnt latke s better but boggieman has everything while burnt latke dosent have TOO many optiones specially for begginers, like they dont discuss barrels, or different ignitiones other than stunguns... or stuff like that..eh I dont know.. their both good sites I guess

Look through the whole site and you will find more, especially in launch examples. He tests various barrels there.

thanks you guys, this is valuable information. i just wonder who the gods are that made those sights.

one last question how do you tell the difference between pressure rated abs and cellular core.

Usually ABS isn't pressure-rated, but I believe it is easier to get pressure-rated ABS in colder areas due to the fact that PVC gets brittle at low temperatures. Be ready to shell out the $$.... Unless the pipe has a pressure rating written on it, it is UNSAFE to use it under pressure.

Like the cannon the size is small enough for practicality, but big enough for "HOLY CRAP"s from your friends when they first see it

johnrodgers wrote:one last question how do you tell the difference between pressure rated abs and cellular core.

The gods?

Lol, boogiman and latke. (latke is some work to do with potato, not his actual name...I think- or is that latka...)

Here are your gods:



It will say on the side. Pressure rated is few and far between, but cellcore is plenty enough for a 1x combustion. It also fails nicely.

bad news i have the cellular core, do you mean when it fails it isnt catostrophic or are you being sarcastic? i was thinking since we already assembled it all i could some how go about re enforcing it, what are you're guys thoughts? as long as i dont goon it up and load a dumpload of hairspray in there i thought i might be able to get away with it. but then again i am a noobie.