| Railway Preservation News https://www.rypn.org/forums/ |
|
| warning about grindling aluminum https://www.rypn.org/forums/viewtopic.php?f=1&t=2328 |
Page 1 of 1 |
| Author: | Alan [ Mon Dec 03, 2001 3:56 pm ] |
| Post subject: | warning about grindling aluminum |
did anybody else get this warning in an email? > > > > Below is an extract from a car enthusiast magazine which describes very > > graphically what can happen if you mix two metal oxides, which > > individually are relatively harmless. Something to be aware off if you do > > much DIY or are a car enthusiast yourself. > > > "SAFETY ITEM > > Most engineers are aware of the danger of grinding aluminum and steel or > > cast iron with the same appliance. > > I'm sending the following details of an incident that has happened to me > > while using a 1" belt grinder. > > In January I was using the grinder to smooth the edge of a hacksaw cut on > > a 2" length of 1.1/2" angle iron. I had been grinding for about 1.1/2 to > > 2 minutes when there was a loud 'thump' accompanied by an approximately > > 2ft diameter brilliant yellow-orange fireball. The fireball lasted not > > more than half a second and then completely extinguished itself. It > > completely enveloped the machine and my hands to halfway up my forearms > > and to the top of my stomach. > > As soon as it went out it was obvious that I had suffered some serious > > burns to my hands, as besides large white areas on the heel of each thumb > > and the palm of my left hand, the skin was hanging from the heel of both > > hands from my little finger to my wrist and from the finger joint of my > > left hand. Also the right cuff of my shirt was smoldering, my face felt > > burning, and I could hear the front of my hair sizzling. Nothing on the > > bench was burning. The only evidence was a few streaks of white powder on > > the bench top and on a few items lying on the bench. The workshop was > > filled with dense white smoke with very little odour. > > Initially I could not understand how I could have suffered such severe > > burns from such a brief exposure to the heat. Later that evening after > > some thinking and questioning of my son (who also uses my workshop) it > > became clear what had happened. > > A few days earlier he had ground the heads of about 12 aluminum pop > > rivets. Finely divided aluminum mixed with finely divided ferrous oxide > > produces a compound called thermit. > > Thermit is used to fill incendiary bombs and commercially to weld large > > steel items, i.e. railway rails into continuous lengths. It burns at > > approximately 3500?C (6300?F) hence the extensive burns from such a short > > exposure time. The end result was, excluding my fingers; I suffered deep > > second-degree burns to about 60% of my left hand and 50% of my right hand. > > In light of my experience, I feel there should be a very strong warning > > passed on to the readership as to the dangers posed by grinding steel > > after having ground aluminium, unless the machine is thoroughly cleaned of > > all aluminium dust. The potential is certainly there for even more > > serious injury." > > > adofmsu@aol.com |
|
| Author: | bob K [ Mon Dec 03, 2001 4:39 pm ] |
| Post subject: | Re: warning about grindling aluminum |
Another hoax Alan. Robert@trainorders.com |
|
| Author: | bob K [ Mon Dec 03, 2001 4:50 pm ] |
| Post subject: | thermite/aluminum info |
Here is some info I found searching Thermite. A search on grinding aluminum did not turn up any warnings. I copied the text, the photos didn't add to the topic. The reaction being demonstrated below is called a "Thermite" Reaction. Thermite is a generic name given to high temperature reactions between a metal oxide and aluminum. The thermite reaction shown here is the single replacement reaction between iron(III) oxide and aluminum to produce aluminum oxide and elemental iron: Fe2O3(s) + 2 Al(s) Al2O3(s) + 2 Fe(s) + heat As the equation shows, this reaction releases heat energy and is thus considered exothermic. The standard enthalpy change in this reaction is -849 kJ/mol (DH° = -849 kJ/mol). Thus 849 kJ of energy is released for every mole of iron(III) oxide that reacts!! With such a large amount of energy being released, the temperatures produced can reach values as high as 2200 °C!! Since the melting point of iron is 1530 °C, the iron produced in the reaction is actually formed in the liquid phase at temperatures well above a thousand degrees celsius!!! To start the reaction, a sample of the thermite mixture, powdered aluminum and iron(III) oxide, is placed inside of a clay pot. The reaction is ignited by inserting a burning sparkler (remember, even exothermic reactions absorb some energy, but even more energy is produced). The reaction then proceeds by releasing lots of energy in the form of both heat and light. Molten iron is seen to drip out of the bottom of the clay pot and into a pile of sand placed below it. The liquid iron will continue to glow and emit heat for several minutes until it cools to a hard, black solid. Robert@trainorders.com |
|
| Author: | John Stewart [ Mon Dec 03, 2001 9:46 pm ] |
| Post subject: | Re: warning about grindling aluminum |
> Another hoax Alan. Well, if it is, then the model engineer who states that it happened to him has sure fooled a lot of people; and faked some good photographs of his hands. I'll try to find out where I saw it; it was either the Vancouver Island Model Engineer newsletter, or the one from Burnaby (Vancouver, BC) Why an older model engineer would try to spoof his fellow clubmembers is beyond me. No, I don't think it happened April 1st. John Stewart Ottawa. john.stewart@crc.ca |
|
| Author: | John Stewart [ Mon Dec 03, 2001 9:59 pm ] |
| Post subject: | Re: warning about grindling aluminum - found it |
Found it! Google is a great search engine. http://www.steammachine.com/vime/index.html - and get the March/April newsletter (PDF format) and look at page 7. John Stewart > I'll try to find out where I saw it; it was > either the Vancouver Island Model Engineer http://www.steammachine.com/vime/index.html john.stewart@crc.ca |
|
| Page 1 of 1 | All times are UTC - 5 hours [ DST ] |
| Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group http://www.phpbb.com/ |
|