aa92td Posted November 1, 2011 Share Posted November 1, 2011 Hello there , its been a while since i was here last time, but i need your help guys. at the last few months , I'm working on thermites project , that should be relaible for long therm use, and that i will be able to ignite them even after months of mouistness , correctrly i'm using the Black iron oxide - aluminum formula binded with sodium meta silicate and press of 3 ton. lets say that i'm having some HUGE troubles of ignitions , my only solution was boron potassium nitrate but it's to expensive for a hobby. So i tought about regular electric ignition with Fe2O3-Al binded over to prime the Fe3O4 thermite , and i'm also not sure about the sodium meta silicate as the main binder , i tought of using nitrocellulose as a binder but i dont know if its will be relaible enough and if it's sure to press it under 3 tons weight. i will be very happy to hear your ideas about ignition and binders.thanks a lot and sorry if there is any english mistakes.cheers. Link to comment Share on other sites More sharing options...
Potassiumchlorate Posted November 1, 2011 Share Posted November 1, 2011 Magnalium/Fe2O3 1:3 ignites most things. Link to comment Share on other sites More sharing options...
aa92td Posted November 1, 2011 Author Share Posted November 1, 2011 tought about it, but magnalium in big amounts is very expensive. Link to comment Share on other sites More sharing options...
50AE Posted November 1, 2011 Share Posted November 1, 2011 If you do it yourself, MgAl becomes the least expensive metallic fuel (at least for me). Link to comment Share on other sites More sharing options...
dan999ification Posted November 1, 2011 Share Posted November 1, 2011 tought about it, but magnalium in big amounts is very expensive. how much do you need, its not all that expensive here so much so that i have bought some cheaper than i can make it. dan. Link to comment Share on other sites More sharing options...
oldguy Posted November 1, 2011 Share Posted November 1, 2011 tought about it, but magnalium in big amounts is very expensive. Homemade mg/al is not that expensive, nor hard to make.(once you find & gather the things needed)Check out this thread....... http://www.amateurpyro.com/forums/topic/6326-water-quenching-diy-mgal/ Nor do you need large amounts, if you formulate thermite prime with it. Link to comment Share on other sites More sharing options...
Mumbles Posted November 1, 2011 Share Posted November 1, 2011 I think your ignition problems at least partly stem from your choice in binder. Sodium silicate is widely used in pyro to fire-proof items and resist erosion of nozzles and vents. If NC doesn't fit your bill, perhaps using something like a phenolic resin, or a resin of another sort to bind and waterproof. It might also be just because it's pressed into pellets. The lack of surface area works against you in ignition. Can you get silicon powder? It can be made to burn almost as hot as boron primes. Adding in Ti or Zr may also help to increase flame temp, and ignition. Link to comment Share on other sites More sharing options...
Arthur Posted November 1, 2011 Share Posted November 1, 2011 Do you need a binder? Some well pressed comps have no binder. Most things that store well are packed well, Cardboard sleeve and ends and then dip it in wax, then weld it into a thick gauge polythene bag and pack in cardboard box LABELLED. If you make a solid plug then you are trying to light the outside, If you make a small cavity for the prime than you are trying to light the inside which is usually more successful. Silicon helps primes because it burns to form fused silica slag which keeps the heat inside the prime where you want it, Al and Ti make a hot smoke which is heat produced that isn't priming the main charge. Link to comment Share on other sites More sharing options...
asilentbob Posted November 2, 2011 Share Posted November 2, 2011 Yes silicates in general tend to be fire retardant and/or refractory. What size/shape are the particles of iron oxide and aluminum? You could probably press it into a tube as Arthur suggests. And having the ignition point in a cavity is a very good way to insure ignition. If the aluminum is fine enough it is fuse sensitive, however it really sucks for formation of a good nugget of iron as too much of the aluminum will burn up in the air. Aluminum already coated with sterin may hold together better than uncoated... dunno. Once pressed, you could probably just store the pellets or whatever their final form is in ziplock baggies or something. Maybe an ammo can. I don't foresee oxidation of the aluminum screwing up the thermite unless the pellets were essentially left outside to the elements for a prolonged period of time. Link to comment Share on other sites More sharing options...
Short5 Posted November 2, 2011 Share Posted November 2, 2011 Iron Oxide/Al thermite is easily mixed with NC and lightly pressed into a paper tube wrapped with tape. A dash of potassium perchlorate and icing sugar(70/30) on top is easily lit by a piece of visco and will light the pellet which burns a bit slower than loose thermite. I am not sure what the effects of pressing it as hard as three tons will have. Link to comment Share on other sites More sharing options...
psyco_1322 Posted November 3, 2011 Share Posted November 3, 2011 I'd try resorcinol glue, it is a very good marine adhesive that is fair pyro friendly, in the fact that it burns up very well and not a lot is needed for a strong bonding in pressed or hand rammed items. If that is not available, I would suggest the use of plaster of paris, as its an oxidiser that can be reduced by Al, you could just formulate your thermite to have a little extra Al in it to use that up also. There is a plaster incendiary that I've seen around that is formulated as 60:40 Plaster:Al. A more modified version of the plaster paste could be made with a more reactive metal like Magnalium or Mg, and could possibly be used as prime. Maybe with some silicon as Mumbles suggested. If the right type of Ti was available, something that could take fire by fuse and burn white hot, that would be an excellent starter prime. I doubt you have any Armstrong Ti laying around though Pressing into a casing would be nice, if you had some available. I would think that a metallic casing would be better if the intents of the thermite where to direct the flow of liquid metal downward. A steel casing would heat up and possibly deform but would keep the spray of molten slag more confined, like a flower pot usually does. Link to comment Share on other sites More sharing options...
xBangergoosEx Posted November 6, 2011 Share Posted November 6, 2011 Works for me, not the best though. Link to comment Share on other sites More sharing options...
Mumbles Posted November 6, 2011 Share Posted November 6, 2011 You'd be surprised at how terribly that's mixed if you screened it. Link to comment Share on other sites More sharing options...
aa92td Posted November 6, 2011 Author Share Posted November 6, 2011 xBangergoosEx :Thanks for that, but as i said before compositions with KNO3 are hygroscopic , and i'm also need to keep the thermites charges for long therm use , and Al\KNO3\S is not the safet composition for long term use. About switching the binder to Nitrocellulose , i tought about it, and i also can get lots of smokeless gunpowder that contains lots of NC , i will check this option , but is it safe to press NC? one more thing, Mumbles lets say that i can get some silicon powder , what am i suppose to do with that? Link to comment Share on other sites More sharing options...
oldguy Posted November 6, 2011 Share Posted November 6, 2011 (edited) one more thing, Mumbles lets say that i can get some silicon powder , what am i suppose to do with that? Name: Fence-post primeType: PrimeSource: Eugene Yurek Potassium Nitrate 65 Charcoal Airfloat 12 Sulfur 10 Diatomaceous Earth 5 Silicon, 325 mesh 5 Charcoal, spruce, ball milled 3 Cut & pasted from <http://www.amateurpy...__1entry36478> Said to ignite a wet fence post in a hurricaneI didn't have any spruce charcoal, so I replaced that 3% with a mix of -100 +300 mesh mg/al.Works like a champ with everything I primed with it. Edited November 6, 2011 by oldguy Link to comment Share on other sites More sharing options...
Recommended Posts