help with igniteing

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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fastcannonman
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Thu May 31, 2007 9:32 pm

i built a pritty nice combustion cannon the other day, and i tested it out today. (i made shure all the glue was dry). my chamber is a simple one. 3" pvc pipe, two screws a quarter inch apart. and a bbq igniter. everything works, but when i put the hairspray in, it wont ignite. ive put small amounts of hairspray in, to larg amounts. its not just lightin. could anyone plz help me on how to fix this problem??
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Pete Zaria
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Thu May 31, 2007 9:36 pm

The most common problem is too much aerosol. A half second spray is usually enough. Try using almost none and work up from there.

Another common problem is that the fuel and air aren't mixing well enough - this is why we use chamber fans. An old computer fan and a 9v battery will do the trick.

Are you venting out the chamber between shots to make sure the exhaust gases from the previous shot aren't messing up your fuel/air mix?

Try some other fuels. If you don't have the money to build a propane meter (one can be built for around $30...) then try carborator cleaner or engine starter fluid.

Peace,
Pete Zaria.
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fastcannonman
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Thu May 31, 2007 9:38 pm

i have a old compter fan in it, but it skips from time to time. i try to air it out using one of thoes air cans. could that be the problem? :?
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Pete Zaria
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Thu May 31, 2007 9:45 pm

fastcannonman wrote:i have a old compter fan in it, but it skips from time to time. i try to air it out using one of thoes air cans. could that be the problem? :?
Quite possibly so.

Switch to a fan that works and try using that without the canned air. I bet that will solve your problem.
Also, seriously, try some other aerosol fuels. Look for engine starter fluid or carborator cleaner.

Peace,
Pete Zaria.
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homedepotpro
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Thu May 31, 2007 9:51 pm

are your screws drilled through the pipe a quarter inch apart
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fastcannonman
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Thu May 31, 2007 9:54 pm

the two end points are a quarter inch apart. sould i moov them farter?
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homedepotpro
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Thu May 31, 2007 10:21 pm

no, if anything closer, sometimes the spray gets on the inside of the chamber and conducts the current around the inside chamber and away from the spark gap
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gotbass7
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Thu May 31, 2007 10:25 pm

just blow and shake a lot. its easier to do then install a fan. install a fan later, and hand mix for now.
Obsolescecne is just a lack of imaginaiton-www.accrc.org
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fastcannonman
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Thu May 31, 2007 10:26 pm

should i put small pices or rubber around the screws at the top on the inside
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pyromaniac
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Thu May 31, 2007 10:33 pm

If you have any oust around try that works great got my smalish combustion. its not a min i its small though. 1 inch chamber and 3/4 barrel.
:pottytrain3:
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fastcannonman
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Thu May 31, 2007 10:37 pm

ok ill try that
SpudBlaster15
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Thu May 31, 2007 11:00 pm

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Last edited by SpudBlaster15 on Wed Jul 14, 2021 3:53 pm, edited 1 time in total.
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fastcannonman
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Thu May 31, 2007 11:02 pm

thanks becuase now i read the back lable. well i found my problem
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