it wont fire!

[baardkaas]

hello there

i'm new in the spudgun building thingy

e made one of 2 bottles taped together (with opposite holes)
at one end a cap and at the other a copper tube about 40 CM long.
as spark i used a lighter spark connecter with some wire that runs into the gas chamber.
the spark is little but i tought that was no problem.
i think the deoderant gets liquid to fast.

can u help me please!

i'm dutch so dont mind the bad grammar

[jackssmirkingrevenge]

Your problem is probably due to improper fuelling, have a look through this thread for some advice.

Since you're Dutch, you might want to join here - brand new forum and still picking up but it will be more relevant to your material and linguistic needs

[Ragnarok]

the spark is little but i tought that was no problem.
i think the deoderant gets liquid to fast.

Possible problems:

- You may be spraying the deodorant over the spark gap, which could prove an electrical short.
- But more likely, you're using the wrong amount of fuel (probably too much). Too much fuel won't light, and is as bad as too little. Try being as sparing as possible on the fuel and see if that will work.

[jackssmirkingrevenge]

One other thing:

2 bottles taped together

... will probably blow apart on firing

[psycix]

Hi there. I'm dutch too welcome to spudfiles.
The two bottles will surely blow apart... if it doesn't blow the first time, then it will blow another time.'
Go to your local hardware store, (gamma, of karwij ofzo) and buy some PVC pipes (thick-walled) and some proper PVC glue.

Oh one minor note: combustions are illegal in our country. Pneumatics are legal-ish when used in your own backyard.

[baardkaas]

5 euro's of tape will stick.. (special repair tape end a lot of cheap tape)
i tried it first with normal stickband (sorry cant translate)
and yes it was a boom (and a pretty hard one)

@ ragnarok
so if the wire gets wet it wont spark ?

that would explain a lot.

and a too little spark does not exist ?

i tried 2 kinds of deo
first i tried axe afrika but did not do a thing.
then i tried some that was real fine cloud like spray i got one "poof" and now i'm breaking my head over how did he bang so easy when i used bad tape and now after a real thick layer of tape he wont do it.

[Ragnarok]

5 euro's of tape will stick.

Spudguns are not something where I would recommend low standards in construction. 5 euros of tape might seem like a lot (and I'm sure it is) - but the question is "Is it enough?"

so if the wire gets wet it wont spark?

Depends on how it gets wet. If there's liquid connecting the two prongs across the chamber wall, then the spark will run through that in preference to jumping through the air, because of the MUCH lower resistance.

and a too little spark does not exist?

Small sparks don't help, and it is possible for a spark to not be energetic enough to ignite a mix, but in your case, that seems unlikely. However, try shortening the wires you're using (if that's possible), because that may help.

[jackssmirkingrevenge]

and a too little spark does not exist?

What's the size of your spark gap?

[baardkaas]

1 or 2 mm
a little too small i guess

@ ragnarok
thnx for the warning
but i'm a trail and error fan

[jackssmirkingrevenge]

Too small, go with 5-7mm

[Ragnarok]

Thanks for the warning, but I'm a trial and error fan.

You'll be less keen on it if you manage to injure yourself. I have nothing against trial and error where an error is neither dangerous nor expensive, but I have enough scars as proof of my mistakes already.

Seriously, this is not a place to mess around with trial and error. People have been killed or maimed by chambers blowing apart - unless you fancy dying or losing an eye, I'd seriously recommend you start to take spudguns more seriously.

[jackssmirkingrevenge]

People have been killed or maimed by chambers blowing apart

Not by spray and pray combustions, surely...

[Ragnarok]

Not by spray and pray combustions, surely...

I was sure you knew this story.

I couldn't tell you off the top of my head whether it was a spray and pray, but there was the guy who was struck in the chest by a combustion's clean out cap, which hit him hard enough to disrupt the rhythm of his heart.
It is a rare occurrence to be hit in the chest hard enough at the particular point during the heart's cycle for it to send the heart into fibrillation, but it can happen.

Whether or not the spudgun in that story was a spray and pray (and I suspect that it may well have been), it could certainly happen with one, particularly one where build standards are lax.

EDIT: You do know this story. I've just found the original topic on Spudtech, and a certain "fullmetaljacket" was one of those who responded.

[psycix]

Try to use less fuel. With a deodorant can the shortest press you can do would be enough to fill your chamber. Don't go PSSSSSSSSSSSSSH for more then half a second, and vent the chamber with fresh air after each shot (or non-shot).

Dus altijd eerst verse lucht erin en dan een klein beetje brandstof.

[psycix]

Too small, go with 5-7mm

Doesn't really matter. 1mm seems like a good spark gap to me.

EDIT:
Sorry for the double post.... I want the delete function back!