woodwalker Posted January 31, 2008 Share Posted January 31, 2008 I need to cut a piece of angle iron, but do not have a big saw, so I though " Why not use thermite? I have iron oxide and aluminum, and Ill use magnesium from a fire lighter to light it." I got some iron oxide, put it in a pestle and mortar, and ground it up pretty fine. Then I got some aluminum and work hardened it, before filing it, then ground up the filings the best I could in the pestle and mortar. I then proceded to shave the magnesium off of the fire starter. I decided to do a test run, so I got about an eighth of a teaspoon of both aluminum filings and iron oxide and mixed it together. I put the mixture on what I wanted to cut, and dumped the magnesium on top of it. I threw a match onto the magnesium, which burned, but the thermite never ignited. Why didn't it work? Should I have measured the iron oxide and aluminum in terms of weight, not volume? Should I have mixed the magnesium in with the other two ingredients? Quote Link to comment Share on other sites More sharing options...
eburgblue Posted January 31, 2008 Share Posted January 31, 2008 Thermite is some really cool stuff when used properly..... you could use a "shaped" dynamite or nitro or semtec too........ best advice...... quit screwing around with xxxx that's not meant for the job..... buy a torch or take it somewhere to get it cut safely. If you want to mess with things like Thermite please at least take a course in pyrotechnics or chemistry before you hurt yourself or someone else! Quote Link to comment Share on other sites More sharing options...
Finnr Posted January 31, 2008 Share Posted January 31, 2008 Playing with thermite is an excellent way to wake up dead. Don't mess with it. Finnr Quote Link to comment Share on other sites More sharing options...
Ice Czar Posted January 31, 2008 Share Posted January 31, 2008 aluminothermic reactions are dangerous in and of themselves, they can be far more dangerous given a few uncontrolled variables. But the blanket warning of "don't do that" around here is beginning to rub the wrong way. Are there better safer ways to cut that angle iron? Probably, but then he didnt mention how thick it is either. Would a thermite charge actually cut it completely? Hard to say, it will burnout what it hits more likely than not. Is it better to feign ignorance and allow someone who is already actively trying to set off a thermite charge proceed by trial and error? Or should we explain the dangerous variables? I think that is a no brainer. 1. mix ratio, 2x > 3x oxide to aluminum very well mixed 2. preheated thermite can almost instantaneously burn, going off too fast to move to a safe distance 3. generally ignited by a strip of magnesium, not filings 4. flash burns and intense UV light dictate welding leathers, gantlets, and hood 5. anything that hot coming into contact with water or a damp material can flash heat to steam, with explosive effects 6. can vaporize toxic metals you do not want to breath 7. not an indoor activity, since it contains its own oxygen source and intense heat, its nigh on impossible to extinguish I too would advise a more appropriate solution to cutting the steel on the other hand, thermite welding, thermite foundry work, and blowing that safe at the Federal Reserve are more appropriate uses of thermite :p Quote Link to comment Share on other sites More sharing options...
RainsFire Posted January 31, 2008 Share Posted January 31, 2008 try buying aluminum powder and red iron oxide at a paint shack.. that eliminates a few variables.. and ya, use a magnesium strip.. which I think you can get at a hobby shop? or I think somewhere that deals with magnesium roofing? I could be totally wrong but I heard somewhere about that.. Quote Link to comment Share on other sites More sharing options...
habu68 Posted January 31, 2008 Share Posted January 31, 2008 Also check with local law enforcement, possession of a pyrotechnic device may be frowned upon. Another thought, what is the chemical structure of spent thermite? At the reaction temps it would seem that all of the carbon would burn out leaving pure iron. I ask because I have access to the sprues left over from the welding of rail road track they are about 1 1/2 " thick and 10" long. and covered with the sand from the casting pot. I just wonder how they would forge. Quote Link to comment Share on other sites More sharing options...
JohnW Posted January 31, 2008 Share Posted January 31, 2008 My high school chemistry teacher demostrated thermite for our class. She had a small amount in a paper cone in a tripod above a sand box. The flash was impressive, we could hardly get over it, but that didn't explain the laugher from the front on the class room. The thermite had no problem going through 2" of sand and the counter it was resting on, but finally stopped on the cement floor. Quote Link to comment Share on other sites More sharing options...
habu68 Posted January 31, 2008 Share Posted January 31, 2008 Another string on thermite:http://www.iforgeiron.com/forum/f7/thermite-welding-4245/ Quote Link to comment Share on other sites More sharing options...
matt87 Posted January 31, 2008 Share Posted January 31, 2008 I just wonder how they would forge. Standard blacksmith's answer: get it hot and hit it! Can't realy hurt to try I guess, supposing you observe suitable safety precautions for working an unknown material (full face mask, good ventilation, bucket of sand etc.). Quote Link to comment Share on other sites More sharing options...
keykeeper Posted January 31, 2008 Share Posted January 31, 2008 Also check with local law enforcement, possession of a pyrotechnic device may be frowned upon. You have that right, Habu. Laws vary form state to state. In my state, our local fire dept. put on the annual 4th of July fireworks show. Any of us that wanted to help had to go to a "pyro" school, AND obtain proper licensing from the State, individually. Everyone who participated had to have a license. We even had to have an approved magazine to store the shells until the show, complete with multiple locking devices. There are also laws governing the possession of pyrotechnic devices, depending on each devices respective class, as determined by state code. Sparklers, fountains, etc. are allowed to be possessed. Firecrackers, bottle rockets, etc. etc. are a no-no. In these times we live in now, with Homeland Security and such, everything is suspect from the authorities, if brought to their attention. Even people who reload ammunition or shoot black powder firearms can become suspect if not careful as to what they obtain, the quantities obtained, HOW they use it, etc. Better safe than sorry, IMHO. Quote Link to comment Share on other sites More sharing options...
rthibeau Posted January 31, 2008 Share Posted January 31, 2008 But the blanket warning of "don't do that" around here is beginning to rub the wrong way. Incomplete or inaccurate information is worse than being told "Don't Do That!" because you would be encouraging dangerous activity and providing an opportunity for misunderstanding/misapplying that info. Contributing to disastrous consequences would indeed be "rubbing the wrong way". Quote Link to comment Share on other sites More sharing options...
Ice Czar Posted January 31, 2008 Share Posted January 31, 2008 then we should strive for accuracy? it wasn't particularly your post that got me riled up we do alot of dangerous things around here, thermite is but another the injuries just as disasterous as improperly using a powerhammer its easier to scare with information than it is to scare with a blanket denial Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 31, 2008 Share Posted January 31, 2008 Funny a friend at NM Tech was just telling me about their chemistry lab yesterday which was refining Mn and another element using thermite. They had trouble getting it started too and had to borrow a torch from the Geology lab folks. Of course high winds made it hard to light the Mg. Some of the Sprues from RR rail welding will harden, some of them look like wootz when forged at low temps due to the coarse crystallization. Some don't. Quote Link to comment Share on other sites More sharing options...
welder19 Posted January 31, 2008 Share Posted January 31, 2008 Buy a torch, not only will you be able to cut this piece of angle iron but you will a one of the most valuable tools for steel work, however make sure you either take a class or find someone who knows how to use a oxy/acet torch to give you a couple lessons on how to use it. Oxy/acet can be very dangerous if misused or used by someone who doesn't know how to use them. Just my oppinon, but as far as the thermite goes....I have know idea, and sounds like you know just enough to get into trouble with it....so if you going to continue to play with it be careful and try to learn more before you try again. welder19 Quote Link to comment Share on other sites More sharing options...
Alan B Posted January 31, 2008 Share Posted January 31, 2008 I have welded rail road rails with thermite and I can tell you it is nasty stuff. Unless the iron you are wanting to cut is at least an inch thick I believe I would seek out another alternative. If you are set on using thermite, one way to control the flow of molten metal is to place the thermite in a clay pot with a weep hole in the bottom. This will allow the molten metal to flow down and through the piece below it. Please use great care. Quote Link to comment Share on other sites More sharing options...
Marc Posted January 31, 2008 Share Posted January 31, 2008 Could the original post maybe be some kind of troll?? Quote Link to comment Share on other sites More sharing options...
matt87 Posted January 31, 2008 Share Posted January 31, 2008 I'm curious just how thick this angle iron is... a proper hacksaw, a decent blade tensioned properly and a vise will help you cut surprisingly thick iron. Just use proper technique, don't go too fast, and take breaks if neccesary. Quote Link to comment Share on other sites More sharing options...
jeremy k Posted January 31, 2008 Share Posted January 31, 2008 When no power is available - I've used the old trusty "hand hacksaw" takes time but you can get it done if needed. Don't forget about the simple tools - not saying they are easy - just simple:-). - JK Quote Link to comment Share on other sites More sharing options...
woodwalker Posted January 31, 2008 Author Share Posted January 31, 2008 Also check with local law enforcement, possession of a pyrotechnic device may be frowned upon. BAH! I live in talbot county, georgia, and there are crack-XXX houses on the street that I live on. The sheriff has gotten in two or three alcohol-induced accidents. I doubt that a bit of thermite will matter. The angle iron is about half an inch thick, but is really long, so I cant hot cut it in my forge, nor transport it 20 miles to my friends house (he has a welder with cutting head). I followed a few safety procedures when I tried (my leather apron, gloves), and I put the piece in question in the yard. I might be 18, but I generally think things out (or over think them). Quote Link to comment Share on other sites More sharing options...
habu68 Posted January 31, 2008 Share Posted January 31, 2008 Standard blacksmith's answer: get it hot and hit it! Can't realy hurt to try I guess, supposing you observe suitable safety precautions for working an unknown material (full face mask, good ventilation, bucket of sand etc.). That was the first plan when I picked up the sprues two years ago....dang I hate having to work for a living.... Quote Link to comment Share on other sites More sharing options...
habu68 Posted January 31, 2008 Share Posted January 31, 2008 I followed a few safety procedures when I tried (my leather apron, gloves), and I put the piece in question in the yard. I might be 18, but I generally think things out (or over think them). Leather apron, gloves. safety glasses, full hood face mask, welders jacket, steel boot covers will all melt or vaporize with thermite. The only effective protection from thermite is distance. Also remember that once started thermite cannot be put out until the reaction is over. "When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years." Mark Twain Quote Link to comment Share on other sites More sharing options...
evfreek Posted January 31, 2008 Share Posted January 31, 2008 Hi woodwalker. You need to find a fellow high school chemistry student who knows how to do a heat of reaction/fusion balance. 1/8 t of each ingredient will not sever a 1/2" thick angle iron. Plus, thermite is better for demolition than cutting. In our high school chemistry class, the instructor set a few teaspoons on fire. It was not enough to melt through lab tweezers, but it did melt the tool into the blob, rendering it useless. Demolition, not cutting. As for igniting it, you need finer ground mixtures and more of it. Also, if you are in GA, you can probably get ignitacord. This stuff burns HOT! That's because one if the ingredients is thermite. And it lights easily. You can even light it with hammer and anvil. As for your angle iron and hot cutting it, don't mess with the forge. Ground fire. Search the blacksmithin' forum for the phrase. It will get you out of jams with the big stuff. Quote Link to comment Share on other sites More sharing options...
woodwalker Posted January 31, 2008 Author Share Posted January 31, 2008 Hi woodwalker. You need to find a fellow high school chemistry student who knows how to do a heat of reaction/fusion balance. 1/8 t of each ingredient will not sever a 1/2" thick angle iron. Heh, I guess I should have mentioned that I was doing a small test run, as I hate wasting my time grinding stuff that will not work. The ground fire idea does sound good, though. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 31, 2008 Share Posted January 31, 2008 Woodwalker, it may be fine with the local law; but you may not want to get on the bad side of the ATF and sometimes it can be hard to tell what's OK and what's not. Specially as you are out in public on a forum with it it might be wise to err on the side of being discrete, (Be Discrete was the motto of a bagpiping club I once knew) I myself *never* do anything I might get in trouble for---had my son in law the LEO fire the black powder cannon last time he visited...or admit to it in public... Hole in the ground forge and a hot cut will work. I make big hacksaws using a bow saw frame and a metal cutting bandsaw blade cut a tad short for extra tension---cut trolly rail in two with that. I consider it part of my exercise program and ifn you were to see me you'd say I could use a whole lot more exercise! Quote Link to comment Share on other sites More sharing options...
matt87 Posted February 1, 2008 Share Posted February 1, 2008 Don't forget what a self-important backdoor, non-elected, legislating body the ATF can be. Shoelace is a machinegun, donchayaknow... Quote Link to comment Share on other sites More sharing options...
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