Lighting metal fires (and putting them out??)

if you look up fire extinguisher compatibility charts online they'll often only talk about class A B C E and F fires so what is a Class D fire how do we start one and how do we put it out why was this fire extinguisher two thousand dollars and why haven't I finished my thesis yet yeah good day welcome back to another episode of explosions and fire if we consider the periodic table most of the elements are metals right and most of the metals are flammable most of them aren't very flammable so they have to be a fine powder or heated to a high temperature but most metals will react with oxygen and sort of burn at some

point what's more exciting is when you have a metal that's so reactive when you have that Burning metal and you put water on it rather than the fight going out the fire actually intensifies and you generate hydrogen which is a big explosion Hazard so that's a Class D metal fire right so if you take any of these elements and they're burning and you put water on it rather than extinguishing it will only fuel the fire there's quite a few of these elements that are capable of causing a class D5 and a lot of them aren't very surprising though like you've got all this group one elements like sodium and potassium and cesium that are very reactive water at room temperature so of course the fire is also going to be reacted with water and you got all these lanthanite Metals at the bottom which aren't really real elements and are just a conspiracy to keep employing more physics PhD students what I think are the most interesting elements in this group are the metals that are really stable at room temperature both the air and water but once they get in a fire get really carried away and you can't use water on them theoretically you could build a building out of these elements and it would be perfectly stable if extremely hazardous in some circumstances but the bulk material is not really considered to be a fire hazard unless you're really trying to set her on Fire Let's really

try to set it on fire I mean how hard is it to set these metals on fire so for some flammability tests I have plates of three different Metals I've got zinc magnesium and titanium now theoretically all of these are flammable Metals but they're not treated as flammable Metals so what does it take to set them on fire so the first test we're going to do is we're just going to put them under a simple propane blowtorch zinc has a melting point of just over 400 degrees so the propane torch quite readily melts the plate the zinc does occasionally catch on fire it burns with quite a brilliant Blue Flame the Fire doesn't really go on to consume the whole sheet of metal but just the fact that zinc has such a low melting point doesn't really matter how big a bulk block of zinc is in any fire scenario the zinc is probably going to melt and cause a huge Hazard magnesium has a melting point of 650 degrees which is probably on the upper temperature range of what the flow torch can realistically achieve it's also quite a big bit of metal so it takes a while for the blowtorch to get it up to a reasonable temperature the weirdly colored footage is from a thermal camera that I have now the maximum temperature that this thermal camera can read is about 650 degrees so if it reports a temperature of like 700 or 750 it's not accurately reading out that temperature it's just screaming in pain because it's looking at something way hotter than it's meant to be you can probably see where this is going after about three minutes straight of blow torching the Magnesium slowly catches on fire and the whole plate has been heated for such a long period of time that once it starts burning it just consumes the whole block magnesium fires are intense they're not super violent they don't splatter everywhere but the amount of light and the brightness of that pure white light that comes off it I was worried about the cameras and getting their senses burnt on it it's that bright it's amazing I didn't think we would be able to set this whole block on fire with just a blowtorch but it burns it definitely Burns so titanium is definitely one of the metals people refer to when they talk about the class D fires so can we set bulk Titanium on fire well the thing that works against us is titanium's melting point is incredibly High really another thing that works against us is that this isn't pure titaniums it's like 90 titanium this alloy has improved mechanical properties over pure titanium and while I can't find anything online to confirm this my guess is that this alloy is less flammable than pure titanium is as such the propane torch is not able to set the titanium plate on fire um it just makes it Go these cool colors as the titanium reacts with oxygen in the air and makes a sort of thin film of titanium dioxide which is kind of cool but we're here to see fire how do we set

Titanium on fire now I was going to go out and get different blow torches and step through different gases and get hotter Flames but I think it's only fair we just immediately jump to Extreme Measures if we're talking generating extreme temperatures my thought immediately is thermite I'm sure all you pyromaniacs out there already know what thermite is it's just a mixture of iron oxide and aluminum but what's significant about thermite is that there's no gases generated in the reaction in most pyrotechnic reactions you generate hot gases and those gases disperse which sends your heat away we don't have that in a thermite in fact the reaction product we generate is molten iron and that iron retains all the heat the aluminum oxide doesn't leave either so you get just molten slag foreign on the titanium plate does not lighter on fire at all in fact apart from all the molten iron sticking to the plate is completely fine so we weren't able to damage it even remotely with the thermite so what else have we got um well

something I've always wanted to try is thermate is apparently just like the weaponized version of thermite instead of just having the aluminum and the iron oxide you've also got some barium nitrate and some sulfur the barium nitrate makes the reaction more intense because you've got an extra oxidizer in there which can consume some of the molten iron and a little bit of yellow just makes it more unstable and easier to ignite and smell bad oh by the way this is one of those pyrotechnic recipes I just copied directly from the Wikipedia page I'm sure every military has their own thermate grenade and I'm sure every military uses their own special recipe but someone has just copied this one onto the Wikipedia page and now it's probably a an intelligence leak if you either confirm or deny or correct that recipe on the Wikipedia page so we'll just assume it's correct I love talking about military stuff because you legally can't correct me on it even when I'm wrong so can the thermate make any impact on the titanium plates I mean no nothing at all really this is not going that well can the thermite even light the Magnesium plate on fire yo thermite sucks at lighting fires man what is this you'd think that molten iron would cause the Magnesium to melt but it's just still completely fine it's termite is not as good as you think it is at this point it would be easy for you to say why don't I just bloody scale up the thermite and do more thermite and you make a convincing Point um let's do that all right so we have a bit over 100 grams of thermite in this can here at the bottom we've got a titanium plate and a bit of metal on top here this one is um magnesium all right so we want the Magnesium ideally you catch a fire and maybe that will help titanium plate catch on fire if the burning magnesium Falls onto the burning titanium that's kind of the thinking um that's all the thinking that's involved there's no more thinking than that okay I've also put a square of the zinc metal down as well just so all the metals can hang out together they're all friends you might think it's stupid I've balanced this magnesium plate on top of this aluminum can that's definitely going to melt and then the Magnesium plate will just fall off but you've got to remember that I've studied physics I knew that the Magnesium plate would perfectly bounce and put the edge in the fire exactly at a great point for it to catch on fire the thermite burn for a solid 30 seconds or so and then once the Magnesium plate caught on fire it burned for the next I mean eight minutes it takes a long time to consume that much magnesium it was a pretty well controlled metal fire it only Set Fire to the grass once so you know I think that's okay all things considered this is probably not important but the iron oxide in that thermite reaction used to be Cutlery at my grandma's is that weird I don't know what does that mean anything so yeah we definitely set the Magnesium on fire the Magnesium set the zinc on fire the titanium plate is once again completely fine please give me ideas in the comments on how I could set Titanium on fire it must be possible I want to set the bulk Titanium on fire but for

now I have to declare that it's not flammable and I hate doing that all right so we've managed to light some class d5s but now we have to learn how do we put them out we have a burning magnesium fire and we don't want it to keep burning what do we do how do you put that out all right so this is our class D fire extinguisher this was about 1500 US Dollars which is quite expensive and makes you think that it's filled with some exotic chemical but in fact it's actually filled with sodium chloride it really is the world's most expensive salt shaker the sodium chloride is really inert so it won't react with the burning metal which is pretty rare because burning magnesium or burning sodium is very reactive and react with most things so sodium chloride is chosen to be unreactive and it's got a very high boiling point so in the high temperatures of the burning metal sodium chloride will just melt and form a crust around the metal and stop the metal from reacting with the air for that to work the sodium chloride has to be extremely dry and that's probably one of the reasons this is so expensive it's probably just very expensive because it's a critical bit of safety equipment those who need it really need it and you need it to work exactly when you want it to I don't think it's overpriced for what it needs to do if we look at the label here you see that it is rated to put out a fire of over two kilograms of magnesium which is quite a lot in you need 13 kilos of sodium chloride to be rated to put out I mean it's like 2. 7 kilos of magnesium you can put out a decent metal fire but not a huge one all right it's pretty heavy maybe I'm just weak now let's go start a magnesium fire and then put it out with this thing I'm Keen to use it although we probably should find somewhere where the grass isn't growing because I feel like we'll end up salting the earth I don't know how violent this is going to be so let's go find somewhere that doesn't have so much grass before we set this thing off oh that was fun all right it's nearly the

end of the video but we keep talking about putting water on a metal fire but we don't actually do it we need to demonstrate these things let's put bloody water on a magnesium fire why not I want to say thanks to my patreon supporters for allowing me to light fires and potentially more importantly allowing me to buy the extinguisher to put out the fires oh yeah if you have been suggested to watch this video as part of your training for a new job consider asking for more Hazard pain yeah that's it all right great