SpudFiles

i have heard about using rubbing alchohol in cannons, so i tried it in my small gun (used mainly for experiments). i poured in some & rolled the gun around a little bit & it worked great BUT the fumes built up over time due to the left over alchohol in the chamber and the nect day i hit the button (dry fire) and it went off & scared the crap out of me (it did this several more times until i washed it out).
Anyway, my question was, will using alchohol mist eliminate this problem? because alchohol certainly works well

Try to find some type aerosol fuel. A lot of body sprays work, I have even got air freshener to work.

Problem with rubbing alcohol is that it is a solvent (pretty sure it effects PVC) not to mention I have always had getting liquid fuels to work well.

And to answer your question, you should have better luck with misting the alcohol. It is going to reduce the alcohol in your chamber, but it will most likely leave alcohol behind and may bring you back to the original problem.

One thing is that rubbing alcohol is not entirely alcohol. You should try to extract as much alcohol as possible. You can filter it or evaporate the alcohol into another container. And yes, you should atomize it as well.

would a fan work to blow the fumes out?

would 80% alcohol work ?(my dad has a lot of 5 liter cans to sterilise)

There is another problem as well. In order to fuel an average size chamber accurately, you will need to be able to measure the alcohol to .02mL or so, then vaporize it when injecting it into the chamber. While you could probably throw some in and try to ignite it until there is enough vapor to do so, (basically what you inadvertently did) there are many fuels that are a lot easier to work with.

Well it seems you have a very small cannon for .02 mL for fueling. After a certian size a chamber using alcohol will fire again, if vented, without fueling it again. My record is 7 times on one fueling. If the cannon is small enough you can just use a cotton swab and rub the alcohol on the inside of the chamber. This makes it consistent and uses the least amount of fuel. What size mini are we talking about here?

I use rubbing alcohol for my mini cannon all time. I use a spritzer to spray it in the chamber and its good to go. I bought 99% rubbing alcohol from walmart and its VERY powerful. With one spray I get about 4 good shots cause it doesnt seem to burn it all the first time. Just make sure its atomized and it's fine.

99%?!?! I've never come across such a concentration. I'll have to look into this. As far as atomization, I always have to blow out the chamber after I fuel my minis. This means that the vaporization of the fuel on the chamber walls is more than sufficient to fire it multiple times.

I'm gonna call BS on the 99%. Alcohol absorbs moisture out of the atmosphere like nobody's business. As a result, even reagent grade alcohol purchased from chemical supply houses tends to be on the order of 95%.

It's pretty easy to distill store alcohol to higher concentrations. I've done it plenty of times myself. Then again I have a whole buch of chemistry glasses. It could be possible to make a distiller.

rcman50166 wrote:Well it seems you have a very small cannon for .02 mL for fueling. After a certian size a chamber using alcohol will fire again, if vented, without fueling it again. My record is 7 times on one fueling. If the cannon is small enough you can just use a cotton swab and rub the alcohol on the inside of the chamber. This makes it consistent and uses the least amount of fuel. What size mini are we talking about here?

That is not the fueling volume, it is the meter's resolution, and is based on a roughly 4L chamber. If you only want to inject enough fuel for one firing, and do it accurately, that's how precisely it should be measured.

rcman50166 wrote:It's pretty easy to distill store alcohol to higher concentrations. I've done it plenty of times myself. Then again I have a whole buch of chemistry glasses. It could be possible to make a distiller.

Ethanol's azeotropic at 95.6%, and thus it cannot be distilled further. Isopropanol is even lower, at 87.9%. The proper term is "a still" BTW, not "a distiller".

LoL spudguns, moonshing.... what 'll be next ?
somethink tells me that police won't belive you that you are doing all this to safely launch potatoes

I've seen Isopropyl Rubbing Alcohol at the pharmacy where I work that claims to be 99%, so it does exist. Whether it is at the concentration it claims to be at, I have no idea.[/quote]

I own a bottle of 100%.
If you dont believe me ill get a pic.

But I have used this 100% alchohol stuff and put it in a spray bottle to mist it and it has worked very effectively, not having this problem you have.