Chemistry buffs...

[Cigaro]

I'm playing with unconventional designs of exhaust mufflers at the moment on the C70. (Just because I'm bored and my other bike is off the road).

What I've come up with is a large guinness can full of steel wool. The end is cut off, the linkpipe goes in that end, and the gases escape through the drinking hole at the top. It seems to provide the right amount of backpressure, and sounds good (not too loud - the steel wool seems to work well to absorb the sound).

It might even become a permanent fixture on the bike.

Only problem is. Somewhere in my cannabis-addled memory of A-level chemistry, there is a little lightbulb that is flashing at me. Something about iron oxide (or rusty steel wool) and aluminium (for instance, a can of guinness) making thermite (a highly flammable material that isn't a good thing inside a hot exhaust system).

Am I worrying about nothing? Would there be enough oxygen in the exhaust for it to actually burn? Would it get hot enough? Would the two materials even react in the first place?

Cheers.

[Itchy]

Didn't Nath do exactly that but instead of using wire wool he used those green scouring pads and brillo pads?.

And erm Thermite has its OWN ie the oxygen attached to the Fe oxygen supply its why thermite can't be put out with water and and it burns underwater.
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[Cigaro]

Scouring/brillo pads are still made of steel wool (well, you can get nylon ones, but they'd melt).

Thing is, I know that the conventional method of making thermite is to use powdered aluminium, so I'm wondering if it would react with the smooth surface of a drinks can very well...

[jack_zxr400]

put a video of it up on youtube so we can see
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Previous Bike: ZXR 400
Current Bike: R6
Test Date: 8/8/2008-PASSED

[Itchy]

[The Shaggy D.A.]

The ignition temperature for thermite is 800-1000 degrees C, whereas exhaust temperatures are around 400-700 up at the header, so it's extremely unlikely you'd get any fireworks down at the can end.

Might want to avoid making it backfire though
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[cyberglass]

if the can starts to powder and mix with the oxide you could possibly get thermite but i cant see it lighting as if the mix isnt near enough perfect its a pain to light up

Also you would notice if the can has started to powder though as the metal is so thin it would get holes in fairly quick and well before you have enough thermite to pose a hazard.


But im no scientist i just play with the stuff so i could be wrong and you could burn off you foot or something
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[GhostRider]

IIRC the inception of a sustainable thermite reaction requires a specific ratio of iron oxide to aluminium anyway, so if something did occur, well, that'd be just plain bad luck.

GhostRider
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[stinkwheel]

From an electrochemical standpoint, the alloy will offer protection from rusting to the iron.

In theory the alloy would all corrode away into aluminium oxide before the iron would start to form rust. The aluminium effectively acting as a sacraficial anode for the iron.

It's a tad more complex than that because rust formation is a third order reaction but what I'm saying is the can should rot away before you get any significant quantity of rust forming.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[stinkwheel]

I should add that I can vouch for the fact that a C90 runs fantastically well on a blue flame end can off a CBR600.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[SoND]

For thermite you need powdered Iron Oxide (red) and powdered aluminium mixed in the right ratio. To ignite it you need temperatures a lot higher than your engine can produce.

If your exhaust makes and ignites thermite then you've broken science and should be ashamed of yourself.
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