thermite won't ignite

[rthmjohn]

I'm having trouble igniting my thermite. I'm using magnesium ribbon as fuse, which is what most people use, so I'm guessing that it has to do with the ratio of aluminum powder to rust. I don't have a scale of any sort so I used the densities to calculate the approximate volumetric ratios which came out to be (I may have miscalculated) about two parts of rust to one of aluminum. What am I doing wrong?

[YT2095]

Mg ribbon will lose all its heat when the thermit pile absorbs it, and so it`ll extinguish.

 

traditionaly thermit is done in stages, you`re missing at least stage 2

 

btw, what`s the thermit for?

[budullewraagh]

also, you may want to make sure your reagents are mixed very intimately. a good way to do this is to add a little ether and stir. then just let the ether evaporate off

[akcapr]

your pieces of rust or aluminum may be too big. Last time i tried thermite the aluminum fililngs were to big, and so the thermite was hard to light, dint light at all actually. THe proportions have to be right and all the ingredients have to be small and mixed well.

[Mendelejev]

I use sugar, some glycerin and H2SO4 instead of Mg. That works great !!

[YT2095]

it doesn`t actualy.

[akcapr]

mendeleev, sorry but that would do absolutely nothing but maybe snoke- it thin k u mean potassium permanganate. that and glycerine is used pretty often to light thermite

[rthmjohn]

the aluminum is fine powder (2 micrometer particle size) and the rust is also fine powder. They look very well mixed too. Is there a specific color the mixture should be to indicate a nice ratio, like pink or light red?

[H2SO4]

I have ignited thermite before with Mg ribbon. I think its all about placing the ribbon correctly.

[Mendelejev]

mendeleev, sorry but that would do absolutely nothing but maybe snoke- it thin k u mean potassium permanganate. that and glycerine is used pretty often to light thermite

 

Yes, indeed. I was confusing the two methods I've tried so far.

 

1. Sugar + KClO3 and some drops of sulfuric acid

2. Glycerin and potassium permanganate.

[H2SO4]

maybe granulated Mg mixed with some oxidizer to for a powder. This should burn extremely hot. If you do this, dont grind, its potential flahs powder.

[akcapr]

dont hope on lighting ur thermite until u get the mixture right. try geting a scale.

[rthmjohn]

I'm investing in one currently.

[YT2095]

use a sparkler, the sort used on birthday cakes, they`ll light even a Bad mix!

 

although I`m still curious What you want Thermit for?

[jdurg]

Probably for the same reason people want sodium/potassium metal, nitrogen triiodide, nitric acid, etc. They hear about the high reactivity and have a major urge to try it out themselves. Or they see a demonstration of it and want to try it out on a larger scale. When you haven't seen it done that often, you think it's the coolest thing in the world. Once you've seen it done a few dozen times, or once you've been injured or nearly been injured by it, it loses its 'edge' and becomes a ho-hum type of thing. That's pretty much my feeling on reacting alkali metals with water. You can only do it so many times before it becomes somewhat boring. However, I don't really think we should think any less of people who want to try these experiments out. If it weren't for my urge to try and synthesize nitrogen triiodide, I never would have even begun collecting elements and my interest in chemistry would have dropped considerably. So the best thing we can do is make sure that everyone knows the major risks associated with these experiments.

 

Themit reactions are very interesting to see, but they can go out of control in a blink of an eye. Remember, you're dealing with LIQUID iron here. That stuff is frighteningly hot and will ignite virtually anything it touches. Also, if some water were to accidentally drop into the reaction vessel, it will cause a massive steam explosion and fling molten iron all over the place. This can cause widespread fires and major property and health damage. Thermit is not something to pooh-pooh. It is nasty stuff that should only be done in VERY small quantities unless you have a wiiiiiiiiiiiiiiiiide open field to do this in that has been fireproofed and you have the local fire department around to supervise it. (As you can't just put it out by spraying water or a fire extinguisher on it. You basically have to let it burn out and pray that it doesn't harm anything important).

[YT2095]

I don't really think we should think any less of people who want to try these experiments out.

 

Whoa Nelly!!!

 

no one said or even insinuated that! I`m genuinely curious what he wants Thermit for.

[jdurg]

Whoa Nelly!!!

 

no one said or even insinuated that! I`m genuinely curious what he wants Thermit for.

 

 

Oh, I know YT. I was just saying that pre-emptively as I'm sure we'd eventually get someone posting in here saying 'he just wants to blow something up'. Happens in virtually all forums.

[rthmjohn]

Jdurg is right. I've never done it before, but I have read through all of the precautions. I live in the desert, so there's plenty of wide open space without any plant life whatsoever (save a few scattered shrubs). But just real quick, I recently purchased a scale accurate to the nearest tenth of a gram and had it calibrated. I weighed out 3g of Al powder and 10g of iron rust. I stirred it for a while, and then placed 3g of KMNO3 on top of the thermite. I used glycerine to ignite it, but the only thing that burned was the KMNO3. What went wrong?

[ThermiteMan]

i lit my iron oxide thermite with sulfur andddddd hmm im trying to think. i think it was potassium nitrate.i dont remember off hand. ill have to look it up but all i remember is that it went off really quick when i did it at my friends house. but then i remember when you put your solid iron in water hydrogen sulfide was released. and that SMELT SOOOOOOOOO BADDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD

[latentheat]

It was sulfur and aluminum. Thermite starter.

[ThermiteMan]

Thanks i was trying to remember it lol. but i couldnt remember it since the last time i was at your house.

[akcapr]

try it with magnesium again, or a blowtorch. and if u can get some picture of ur thermite.

[rthmjohn]

I stirred it for a while, and then placed 3g of KMNO3 on top of the thermite.

I meant KMnO4. My bad.

[rthmjohn]

If i light it directly with a torch, will I have enough time to get away? I'm guessing the answer is no, but never hurts to ask.

[akcapr]

oh u will, its not an explosion- ull be able to to get away. Like look at my avatar- im lghting that flash powder with the equivalent of a blow torch, and i got away easily and i got it on film and wasnt hurt at all, and flash powder is a bit more violent than thermite, however thermite can fling hot fragments.