Fuel Needs A Safe Way To Test

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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jrrdw
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Fri Sep 10, 2010 2:39 pm

As a result of discussion here the topic of a safe way to test a product to see if it will be a good fuel for a 'spray and pray' or standard combustion launcher.

What are your idea's on how to test a product safely?
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Fnord
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Fri Sep 10, 2010 3:27 pm

The most simple way would be to exploit the heat conduction properties of steel to transfer external thermal energy from an exothermic decomposition reaction through the containment walls, thereby increasing internal pressure as described in accordance with Charles's Law and PV = nrt (the ideal gas law), until such that, by means of both internal stress and degradation of the yield strength of the vessel through temperature increase, the elastic limit of the material is exceeded and the resulting failure causes the contents to equalize with the pressure of the surrounding atmosphere, eventually forming a stiochiometric fuel-air ratio and absorbing enough energy from the decomposition reaction to initiate an exothermic reaction within the mix. This reaction is easily observed in both the visible spectrum and the far-infrared range, as is demonstrated below:


Video removed by jrrdw, dangerous example!
Bah! that's not fair! I was sciencing as hard as I could!

Or you could look for flammable contents on the label.
Last edited by Fnord on Fri Sep 10, 2010 4:10 pm, edited 1 time in total.
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Ragnarok
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Fri Sep 10, 2010 3:35 pm

@Fnord: That is one of the funniest things I've read in months. :D
Does that thing kinda look like a big cat to you?
SpudBlaster15
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Fri Sep 10, 2010 3:39 pm

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Last edited by SpudBlaster15 on Thu Jul 15, 2021 1:49 am, edited 2 times in total.
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Technician1002
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Fri Sep 10, 2010 3:40 pm

The general concept of will it burn needs to be determined. The question for the thread is how to do it safely. A couple things comes to mind.

1 Location Are you away from flamables, including your clothing? This is a good reason to test outside with flame retardant clothing.

2 Is there plenty of fresh air? This is a good reason to do this outside.

3 Is there a breeze? This is the only reason to test indoors, but in a proper location such as a blacksmith's shop.

4 Is there a backup plan for unplanned accidents? Do you have a way to extinguish a can that is drooling flammable liquid down the side of the can and your fingers due to a plugged nozzle? Is there a fire extinguisher, garden hose, bucket of water nearby?

5 Do you have a buddy to observe and operate the safety backup plan?

I do not recommend spraying into a bucket and then lighting the contents. a large volume of air fuel mix may provide an eyebrow removal fireball. Adding a small amount of the test material to a flame already burning is recommended. A short spray just to see if it burns is recommended.

@Fnord, I think your video is likely to be deleted like mine. It's pretty obvious that is not the safe way to do it.

@SpudBlaster15 Many cosmetic items do not require a MSDS, so they are sadly lacking.

For a good example of this go to this site with many household products and look up the MSDS for White Rain Extra Hold Hairspray. It brings up a PDF explaining why it does not need a MSDS.
http://www.manchestercitysch.org/centraloffice/MSDS.htm
This leaves us with test it yourself.
Last edited by Technician1002 on Fri Sep 10, 2010 3:48 pm, edited 2 times in total.
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Fnord
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Fri Sep 10, 2010 3:43 pm

Yes! I got Ragnarok to use the ':D' smiley.

Guys, initiate phase 2 now.
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jrrdw
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Fri Sep 10, 2010 3:52 pm

Here is a small list of fuels from the Wiki.

Now we need SAFE ways to test them with out going through the pains of using the launcher witch can be very time consuming and aggravating.

Fnord suggested using a bucket, (in the above linked thread). That's a pretty good idea but has some issues. 1) You have to light it quickly. 2) You have the real possibility of getting burnt by a flame ball coming from the bucket when the fuel ignites.

You could wire up a sparker in the bucket with long wires to protect yourself from getting burnt. That would also be a better simulation for the test. What will your type sparker ignite and what wont it ignite.
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D_Hall
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Fri Sep 10, 2010 3:59 pm

Personal opinion: If you don't know how to answer that question, you don't have any business screwing around with new fuels. There are enough tried and true fuels out there; use one of them.
Simulation geek (GGDT / HGDT) and designer of Vera.
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jrrdw
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Fri Sep 10, 2010 4:04 pm

D_Hall wrote:Personal opinion: If you don't know how to answer that question, you don't have any business screwing around with new fuels. There are enough tried and true fuels out there; use one of them.
Yea but the thing is we have new members and a lot of guest viewing all the time. So we need to offer ways to do this safely so the new members don't hurt themselves trying to get the launchers we show them to work.
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jimmy101
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Fri Sep 10, 2010 4:48 pm

jrrdw wrote:Here is a small list of fuels from the Wiki.
Here is another one that is a bit more complete.
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Technician1002
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Sat Sep 11, 2010 11:52 am

One issue with some consumer products and various locations, is various regulations. In the US and now pretty much worldwide, Fluorocarbons (Freon) was banned as a propellant due to the hole in the ozone layer. A replacement many use is butane or propane or a mix. Now there is a push to control Volatile Organic Compounds (VOC emissions) which is pretty much any flammable fumes including gasoline, methane, alcohol, propane, butane, etc.

Due to various regulations, not all products sold in various countries are the same.

The best start is to read the label. Some products have a MSDS, but many consumer products do not. If you get a product tested as fantastic in one country, it may be a dud in another due to an alternate propellant. A safe way to test if the launcher failure is fuel related becomes the issue.
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SpudFarm
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Sat Sep 11, 2010 3:24 pm

Why do someone need to test if their aersol is flammable before fueling the gun with it?
I would just try it..

Just don't use something completely unknown and it should be fine.
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Biopyro
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Tue Sep 14, 2010 7:12 am

Partially inflate a balloon with the fuel, inflate the rest with air from a bike pump. Ignite from a distance.

Of course this isn't a quantitative method, but it tells you whether the fuel will burn, and if done consistently it might be possible to compare fuels .
Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety. -Benjamin Franklin
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jackssmirkingrevenge
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Tue Sep 14, 2010 8:09 am

Fnord wrote:Yes! I got Ragnarok to use the ':D' smiley
lol that's the first thing I thought! Shame I missed the cause before it was removed.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Ragnarok
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Tue Sep 14, 2010 8:56 am

jackssmirkingrevenge wrote:Shame I missed the cause before it was removed.
PM sent.
Does that thing kinda look like a big cat to you?
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