Copper thermite

[Redrocketman]

After talking with SS2S director RM, he has highly advised that I switch to using copper thermite igniters, when firing very large r candy motors. I saw 4 X 75mm 6000ns motors ignited instantly and all at exactly the same time. They pledge by it. Now after a bit of a look around, it's fair to say there is some concern over its sensitivity & explosive nature. Yes it is very reactive. These guys know me very well, know my work practices are sound, safety is no. 1 ( has to be, I solely use PVC motors ) and that I will not misuse or do anything untoward that may hurt or injure myself or anyone in there vicinity. AER group is great, but this forum is without a doubt A1 for getting help in relation to technique, composition make-up etc etc.

Has anyone had experience using this composition for ignition? I have just ordered 1kg of copper, have more Al than I can use so it looks like a winner to me. Wondering how easy it really ignites?. Rick said it will ignite no problem with a mini bulb

Cheers

[NeighborJ]

I will attach a photo of cu termite, used for CAD welding, as you can see it is quite coarse grained. In this mesh size it is not explosive at all but in extremely fine mesh(200-325) it will explode very violently. It is friction sensitive and has been used in exploding targets as a binary explosive.

The cu needs to be cu II oxide for the reaction to take place. I don't think you will have any luck with regular copper dust.

BTW for CAD welds it is hard to light with anything other than a Flint striker. I would think that if you coat nichrome wire with nc laquer and roll it around in the termite powder it should light easy. The nc should prevent any explosive reaction from anything bound within it. But treat the mixed fine powder as if it is flash powder, that means diaper mixing and static proof containers, don't mix more than you will need.

I will attach a photo of cu termite, used for CAD welding, as you can see it is quite coarse grained. In this mesh size it is not explosive at all but in extremely fine mesh(200-325) it will explode very violently. It is friction sensitive and has been used in exploding targets as a binary explosive.

The cu needs to be cu II oxide for the reaction to take place. I don't think you will have any luck with regular copper dust.

BTW for CAD welds it is hard to light with anything other than a Flint striker. I would think that if you coat nichrome wire with nc laqure and roll it around in the termite powder it should light easy. The nc should prevent any explosive reaction from anything bound within it. But treat the mixed fine powder as if it is flash powder, that means diaper mixing and static proof containers, don't mix more than you will need.

Edited August 7, 2016 by NeighborJ

[Arthur]

Remember that it's copper oxide with aluminium. Start small and coarse, get finer and bigger only if you really need. Copper thermite will go high order if it's too fine or too big.

 

For a specialist igniter I can see a use for it. For classic thermite projects it may send molten copper outwards if it detonates.

[Redrocketman]

Thanks mate. Geez if I need to Burn/destroy something ie an expired hard drive the faithful iorn thermite is more than satisfactory!! Sorry I was I bit blasé in my explanation of copper. Yes I know which breed to purchase, I would prefer to keep my posts fairly simple, as we'll never know who's reading.

Not a large amount goes into an igniter, a small amount only needs to be prepared at any one time. I treat any unstable composition with utmost care, and this comp will be treated as such.

As always, take care & be safe all

[Seymour]

The ease of ignition is dependant on particle size. If your CuO is quite fine (I've been seeing stuff that is like fine sand a bit, you want the stuff that is finer than flour) then it is all about the Aluminium.

 

With Dark Flake Aluminium it is very easy to light. Black match will light it, as will an e match or other fuse.

 

With Atomised Aluminium it is likely that you need to light it with something hotter. MgAl fuelled coloured star mixes are usually hot enough, and as such I use a coloured star on a fuse to light this stuff. Specifically most of my experience is with 44 micron granular, which should be about the same as 300 mesh atomised in ease of ignition.

 

 

 

For classic thermite projects it may send molten copper outwards if it detonates.

 

For sure it does, with Aluminium ranging from Glitter Star Aluminium to anything finer. With the possible exception of less fine Aluminium mixes the molten copper is a fine aerosol, not in any droplets or large bits. It's in the form of smoke. very pretty, pink smoke. So long as you stand back a bit there is no risk, and if you are too close, the risk it from the intensely hot fireball more than any molten (or gaseous) metals. Essentially it just acts like a form of flash powder. A pile can do anything from "thump" to "bang".

 

 

 

extremely fine mesh(200-325)

 

For pyrotechnic Aluminium I'd consider that to be on the medium - average area of the range of sizes available. My personal assessment of extremely fine would be the dark flake aluminium with a large fraction of the material being less than 10 micron in diameter.

 

However in almost all areas of life 200-325 mesh Amiminium would be extremely fine! It's just that in pyro, fineness of Aluminium has a whole different set of meaning.

[Redrocketman]

I fire all motors remotely from a long distance ( dababu!! ) I'll post new results when next order arrives ( dark flake Al & Mg )

This comp is only used to fire large AP & epoxy based fuel. I think the s£%t would hit the fan using them with sugar based propellant!

[dagabu]

I eat Doritos with French onion dip! (Redrocketman!!)

[Redrocketman]

He he he

[dagabu]