BenB
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| posted on 26/9/07 at 09:32 AM |
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Talking of magnesium
Following on from the talk of magnesium, there was mention a while back of the importance of cleaning up after angle grinding....
Aliminium will burn very much like magnesium (required temp is higher though)...
One problem in workshops can occur due to the accumulation of grindings under the workbench. Typically an pile of iron (which rapidly oxidises), and
magnesium / aliminium powders.
Whether or not the stories are true I'm not sure but there are reports of sparks setting off the pile in thermite style reactions.... Worth
getting the hoover out every now and again (at least between working on different types of material).
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MikeRJ
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| posted on 26/9/07 at 09:44 AM |
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A good point, though possibly more applicable to e.g. bandsaws as you shouldn't be grinding aluminium anyway!
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Hammerhead
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| posted on 26/9/07 at 09:47 AM |
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forgive my ignorance, but why shouldn't you grind ali?
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BenB
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| posted on 26/9/07 at 09:55 AM |
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Yes but if you don't grind it (even though I do!!) you'll have to file it which will still make lots of lovely ali filings to mix up with
the iron oxide....
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jimgiblett
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| posted on 26/9/07 at 10:05 AM |
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quote:
Originally posted by Hammerhead
forgive my ignorance, but why shouldn't you grind ali?
The ali can melt into the porous gring disc material. When the disc later heats up again it can crack / shatter / explode the disc. High speed
flying bits of grinding disc tend to make a mess of organic matter such human body parts and the like.
- Jim
[Edited on 26/9/07 by jimgiblett]
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blakep82
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| posted on 26/9/07 at 10:08 AM |
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i was thinking about the thermite thing the other day while i was watching brainiac.
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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llionellis
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| posted on 26/9/07 at 10:15 AM |
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True, discs should only be used on the materials specified by the manufacturer. I have only seen one disc explode in 40 years in engineering, I have
to say it was quite spectacular and fortunately no one was hurt.
Discs are available for use on aluminum http://www.tgsindustrial.co.uk/productdetail.aspx?prodid=478&prodgroupid=150
being one supplier of such discs.
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blakep82
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| posted on 26/9/07 at 10:25 AM |
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think i might go hoover up today...
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Hammerhead
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| posted on 26/9/07 at 02:15 PM |
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quote:
Originally posted by jimgiblett
quote:
Originally posted by Hammerhead
forgive my ignorance, but why shouldn't you grind ali?
The ali can melt into the porous gring disc material. When the disc later heats up again it can crack / shatter / explode the disc. High speed
flying bits of grinding disc tend to make a mess of organic matter such human body parts and the like.
- Jim
[Edited on 26/9/07 by jimgiblett]
Thanks for the reminder 
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macspeedy
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| posted on 26/9/07 at 03:29 PM |
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you can buy all the parts for thermite from ebay!!!! think it has to be in quite accurate proporsions 3:1 if i remember 
[Edited on 26/9/07 by macspeedy]
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trogdor
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| posted on 26/9/07 at 08:55 PM |
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I may be wrong but i think that the iron oxide that is needed for a thermite reaction is not the common rust oxide, it needs an iron oxide with a
different oxidation state. i remember trying to start a thermite reaction when i was younger which didn't work, but we did do it at college! the
molten iron produced burnt through three fire proof mats! makes a spectacular bang and cloud of smoke!
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