Up in flames....no pun intended.

Discussion in 'Mistakes, Blunders and Boo Boos' started by cwkelley75, Aug 9, 2012.

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  1. Nov 23, 2019 #41

    MachineTom

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    MachineTom

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    As a kid I used to return deposit bottles to the deli for change. Then go to the hardware store and buy 000 steel wool pads. Then wrap a small candle in paper, then wrap the steel wool around. When dark bend a coat hanger around the steel wool and light it off. Then swing it around, the sparks and all were flying all over, clumps of flame.

    Ahh, to be 10 years old again.
     
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  2. Nov 24, 2019 #42

    Cogsy

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    Thermite is a mixture of rust and aluminum (I said aluminium oxide earlier but that's not correct), Because of the oxygen in the ferric oxide (rust) the reaction can self sustain without external oxygen including under water. It's also a quite a fast reaction (and really cool to watch) that burns hot enough to separate water into its components and burn the hydrogen in the right circumstances (burning water is another cool thing to see). Unconstrained, a thermite reaction will be over in seconds and result in a spray of small, extremely hot particles, spread over the immediate area.

    Magnesium alloy takes quite a bit of heat to ignite, especially in big chunks rather than ribbon form, so in the incendiary bombs they used thermite as a trigger to ignite the big chunk of magnesium alloy, which would then burn hot and long (maybe 15 minutes) with a view to heating up the surrounding environment enough to get a large fire going. I don't know how they ignited the thermite though - that stuff is also reasonably difficult to light (we use magnesium ribbon as a fuse). The magnesium reaction does require external oxygen, so can be smothered with dirt. However it also burns hot enough to separate water into hydrogen and oxygen, so spraying water onto it would literally be adding fuel to the fire, which is why the dirt/turf would have been the preferred method.
     
  3. Nov 24, 2019 #43

    goldstar31

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    Thank you, I now agree! It fits in with my childhood memories.
    In practice then, the Air Raid Wardens were issued with stirrup pumps and galvanised pails to tackle the things.
    There ws TWO settings for the hose end. One would direct a jet of water and was used for normal fires whilst the other created a fine spray which effectively cooled the exotherm down and stopped the reaction. However, as Cogsy rightly asserts a jet of water would cause an explosion scattering still burning magnesium and thermite even further onto roofs Later, there were explosive devices in side to pierce roofing tiles.

    I made brief(?) reference to Alexandra Palace. It had been the scene of early TV which shut down with most things when war was declared. It was replaced with a jamming system of German radio beams which could guide attacking bombers along a line to the target. Unfortunately, secrecy of the device created the Blitz on Coventry with erroneous loss of life. Our visitors to merely picked up the church between Cullercoats and Tynemouth and they then followed the river. But, but we had the sort of replica of Sydney Harbour Bridge across theTyne at Newcastle. Of course, it was bombed repeatedly but missed. I recall a Ju88 having a go.
    But further up the Tyne was a smaller but identical bridge and it was mistaken for the 'real thing', hence my experiences.
     
  4. Nov 24, 2019 #44

    lkrestorer

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    A circumstance that may be a bit closer to home for most people is dealing with small alkaline batteries that have outlived their usefulness. These are listed as items that are acceptable to simply throw in the general trash. In my small home shop there is always aluminum and steel particles and swarf along with paper , cloth and whatever else becomes trash in the receptacle waiting to get full enough to dispose of. Occasionally I have a battery to throw away. Now, go back to the earlier entries above that talk about fires being started with batteries and metal. I make a habit of securely covering the terminals with electrical tape (any type of tape will do - I'm an old electrician) so that whatever "juice" is left in the battery can't start a fire. I even do this in our house waste even though there is little chance of contacting metal (oops, watch out for the aluminum foil!)
     
  5. Nov 25, 2019 #45

    skyline1

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    A sensible precaution as although domestic alkaline batteries especially exhausted ones do not generally have sufficient current capacity to present a major fire risk, in some unusual situations they could.

    Who knows what they could come into contact with in the general waste and you might accidentally throw out a "live" one further increasing the risk.
    In our area we are lucky enough to have separate recycling facilities for them which helps in this respect.

    Rechargeable batteries are quite a different matter especially the very high power LiPO ones used to power model aircraft, drones and the like.
    Heed the many warnings on them carefully, If abused (and sometimes even if not) they can ignite, spontaneously re-ignite and even explode with considerable force.

    I recently met someone who had actually burnt his house down whilst recharging model aircraft batteries.

    Apparently the fire brigade had told him that the only way to deal with them was to contain them and let them burn themselves out as they simply reignite until they run out of fuel

    I could not guarantee this as fact but an Internet search for "exploding LiPO batteries will reveal some pretty scary video footage

    These should definitely NOT be disposed of with domestic waste and I think it is now an offence to do so in the U.K.
     
  6. Nov 25, 2019 #46

    lkrestorer

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    Yes, the rechargeable batteries definitely need to be recycled/disposed of properly. It is illegal for them to be thrown into common trash in the U.S. also. They are somewhat scary in the ways that they react.

    My lesson with the alkaline batteries was seeing a 9-volt battery fall into some steel shavings. It didn't cause any damage but there was a small but exciting display of sparks and it got very hot before the metal burned away and it put itself out.

    There are many 'common' ways that we can hurt ourselves and our surroundings. Please be careful.
     
  7. Nov 25, 2019 #47

    lkrestorer

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    cwkelley75 started this post with a story about him making 'titanium bone screws'. I'm proud / disappointed / scared / anxious (pick your favorite) to say that on December 9th I will be getting some of them installed in my left shoulder along with a collection of various other metal and plastic parts. I'll be a bit wobbly for a while but I hope to get back into the shop for some rehabilitation after the first of the year.

    Enjoy your health when you have it.
     
  8. Nov 25, 2019 #48

    Dubi

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    Every best wish for a safe operation and speedy recovery.
     

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