Water contact with molten aluminum can work on a home scale; on an industrial scale the same contact can behave like molten alkali metal (sodium, potasium, cesium) contacting water. Not just a steam explosion, but something more like a thermite explosion of atomicly fine particles. How does the scale change the result, and what is the trasition point? Unclear. Seems to have something to do with the aluminum still being very hot even after contacting the water. Safest is don't pour into water. If you do: 1 Keep the volume down. 2 Avoid superheating the aluminum.
N-no. I'm recalling a "lead explosion" right now. Thank God for shop-grade safety glasses. A slightly damp "waster" bullet went into the pot, and POP! I had lead droplets on my face. No big ones, thankfully. Moisture and hot metal do *not* mix. I wish I had known that 28 years ago like I do now.
This gets a little more into it. I follow his explainations and observations but it still leaves some questions. Unfortunately I'm not quite bright enough to ask them. Suffice it to say there is more hazard than just steam and for now I'll just have to take the basic safety precautions. Pete
Aluminum is like a tamer version of magnesium... (you use sand, and not water, to deal with Mag fires... Get aluminum hot enough - say, to melt - it becomes a whole lot more reactive. Powdered aluminum is used in solid rocket fuel, and in explosives. Molten aluminum is yet more reactive...
The physics involved is somewhat unpredictable. But simply put: A little metal and a lot of water is usually fine, a lot of metal and a little water is bad. One of the worst cases is insufficient preheating of tools. A very small amount of moisture at close to the boiling point has a very high probability of going boom. I had an episode like that when casting bullets once, dropped a warm, wet ingot into the pot. Got a low "pop" and lead fountain 2 feet high. Managed to back up before it came down, so I just got my work bench covered in a layer of lead sheet. With reactive metals it can get even worse. Even though aluminum appears fairly docile it's still very reactive and energetic. A steam explosion can produce a spray fine enough to catch fire in air. And you do not want to experience that close up.
Turn around. Your preaching to the choir 2 & 3 degree. ER thought I would loose the middle finger ... burn unit sent me home with good narcotics and told me to keep it clean V/r HT1
It is amazing what will burn when aerosolized or reduced to extreme air born fines........grain explosions come to mind, but if you take a handful of wood saw dust (sanding fines) and toss it up into the air or an open flame it will usually produce a flash fire ball. Many powdered metals used for sintering can be similarly dangerous and they burn much hotter and release much more energy. Best, Kelly
For some reason I imagined Rorshach from the Watchmen movie improvising some prison weapon with ignited creamer dust.
Yeah, I respect the guy's research efforts and findings but there's still something missing. From his presentation you would almost have to conclude that pouring aluminum into a greensand mold is like playing Russian roulette with catastrophe, which it clearly is not. I think the hazards for us are much more in the realm of steam events than reactive ones as long as we limit the exposure to water to its use in the sand. Pete
I find his “informative and cautionary” video to be simply an elaborate rather pompous misrepresentation of reality. It serves no useful purpose. Quite the contrary. It should have been obvious to the “scientist” making the video that pouring aluminum into water was perfectly safe if done as shown with large amounts of water in an unconstricted space vs the demo of a large amount of aluminum poured into constrained small volumes of water. Please, give me a break! If their purpose was to actually inform, then they should inform and make the distinction clear. Wanna make a aluminum cannon? I suggest welding a bottom cap on a 10” thick-walled pipe 20 feet long propped vertical. First pour in 1 gallon of water and then 10 gallons of molten aluminum. See, that proves molten aluminum is dangerous, children. Be afraid of it. Don’t try to understand it. You can not use it safely. Oh, and please subscribe and click likes.... Sorry for being grumpy. Denis
I couldn't find the "Subscribe" for your post. I am of mixed feeliings on this sort of subject. I've known plenty of logically-challenged individuals who follow thoughts such as "If gasoline is dangerous and blows up, why hasn't my car exploded?" then they procede to dump gasoline onto a pile of crap to help ignite it...with ensuing hilarity (sometimes). On the flipside, I know of many examples such as this where there's a risk of issues, but FFS the molten metal itself is pretty damned dangerous and if you can't handle it carefully, then the nice book Mr Darwin wrote might apply. That said, I've had a small steam explosion which vomitted molten metal out of a plaster mold into my face when I was a boy; thankfully the volume of metal was small and I sustained no lasting injuries, but it left a deeper respect I didn't have previously. It's all in the scale, be that the scale of materials or ignorance. Largely I'm OK with such provided there's an understanding that safety and sound methods can made even the most dangerous activities manageable; extra credit if they expalin those methods.
I positively agree that appropriate cautions should be made regarding molten metals. But to suggest that steam explosions are purely determined by a roll of the dice is irresponsible. It would be far better to accurately point out truly safe methods and underscore the dangerous ones. But the key is to help folks understand that there are clear principles which, if recognized and accounted for, result in likely disaster or result in safe handling. Those principles have nothing to do with rolling dice. And to suggest the outcome is left to chance is disingenuous and, itself, furthering ignorance. The world needs no help in furthering ignorance. Denis
Before seeing the latest Youtube movie posted on this page, I was only concerned with steam explosions and I still am, as far as casting safety is concerned. I have had one incident, when I placed cold brass scrap into a crucible and I wore hot metal on my face shield. That was a good enough lesson for me and 36 years later, nothing else nasty has happened. To get to back to the movie; the point he claims is that clean molten aluminium can sometimes react at a molecular-level, appears to have some substance. His claims need to be peer-reviewed, but the video "evidence" appears to show much more than a steam-reaction. Take precautions folks. Straddling a crucible with the family jewels might be painful, Cheers Charlie PS Any potential hazard from damp sand, can be totally eliminated by using oil (petrobond) as the binding agent.
