I want to slow down my copper oxide thermite reaction

[Uarbor]

Almost a year ago I purchased a nice supply of copper oxide and 9 Micron atomized aluminum. I was making reactive targets for 22. It was a lot of fun. But I'm trying something new now want to slow the reaction way down and attempt to use it to melt some copper which will be cast into a mold. I have been an electrician for 35 years and copper has been a part of my life everyday. I want to make something out of copper using Pyro. I do have some experience with cad welding of electrical grounding wires using something looking extremely similar to Copper thermite it seems as though the granules are much larger though. I was wondering if I could granulate in the copper oxide and if that would slow things down. I was wondering if anybody had any experience with such a thing? All comments and suggestions are welcome thank you in advance

[Richtee]

I tried that stuff once... about 10 grams on an iron plate. Good thing I used a long sparkler fuse. It self contained and bounced the plate about 10 foot. Be careful...

 

On edit.. won’t copper melt at like charcoal temps? Heap a pile around a metal can full of scrap...

Edited February 10, 2022 by Richtee

[a_bab]

Granulating the oxide will certainly help. Another way to slow it down is to use larger aluminium (as large as 100 microns is used for iron thermite) and to heavily imbalance the reaction by using an excess of copper oxide. But none of this would likely provide you with a nice pool of clean melted copper.

Just use a furnace and melt copper if want to cast. Copper is notorious to give ugly casts with lots of porosity. Bronze solves this issue.

Edited February 11, 2022 by a_bab

[Arthur]

Copper thermites are notorious for being sensitive and likely to go high order.

[kingkama]

Some people use Copper oxide for make Brown smoke report. Edited February 11, 2022 by kingkama

[Uarbor]

Copper thermites are notorious for being sensitive and likely to go high order.

that was the whole idea with the reactive Target. They were a lot of fun Edited February 13, 2022 by Uarbor

[Uarbor]

Granulating the oxide will certainly help. Another way to slow it down is to use larger aluminium (as large as 100 microns is used for iron thermite) and to heavily imbalance the reaction by using an excess of copper oxide. But none of this would likely provide you with a nice pool of clean melted copper.

Just use a furnace and melt copper if want to cast. Copper is notorious to give ugly casts with lots of porosity. Bronze solves this issue.

a big part of my hobbies is doing things the hard way LOL that's why I enjoy blacksmithing and things like that. Same thing with fireworks really. I always pick the more difficult projects to start out with. I think you are absolutely correct a larger aluminum grain size would be the way to go. Whenever you do the cad welding for electrical wires there is a separate Starter Powder which is very fine and then that lights the heavier stuff that does most of the work. It makes a beautiful casting of perfectly smooth copper with the commercial product. But right now I'm just trying to keep it from blowing up. I also found out that alloying copper with a little bit of silicon will actually make it flow much better and make better castings but of course you can't do that with a thermite reaction. I could easily use my blacksmith Forge to melt copper but I am afraid of that because if you spill even one drop in the Forge none of your Forge welds will stick for the rest of your life Edited February 13, 2022 by Uarbor

[Richtee]

So don’t use your forge. Use your grill like I do for charcoal (and burgers and steaks) Yes, I have cooked charcoal and burgers at the same time before.

Edited February 14, 2022 by Richtee

[WSM]

a big part of my hobbies is doing things the hard way LOL that's why I enjoy blacksmithing and things like that. Same thing with fireworks really. I always pick the more difficult projects to start out with. I think you are absolutely correct a larger aluminum grain size would be the way to go. Whenever you do the cad welding for electrical wires there is a separate Starter Powder which is very fine and then that lights the heavier stuff that does most of the work. It makes a beautiful casting of perfectly smooth copper with the commercial product. But right now I'm just trying to keep it from blowing up. I also found out that alloying copper with a little bit of silicon will actually make it flow much better and make better castings but of course you can't do that with a thermite reaction. I could easily use my blacksmith Forge to melt copper but I am afraid of that because if you spill even one drop in the Forge none of your Forge welds will stick for the rest of your life

 

 

That sounds like silicon bronze. I'm a high voltage electrician, plus have also done a fair amount of cad welding in the past.

 

I'm not so certain you can't add silicon to the copper cast. Rail thermite (used for welding railroad rails in the field), has a mixture of materials in it to cast an alloy unique to their needs.

 

I believe alloys are possible with additions made to the basic Goldschmidt reaction.

 

The materials of the base charge are usually coarser to control the rate of the reaction (to make it flowable and not just a spray of molten metal), and use just a tiny amount of fine Al/CuO as a primary charge (first fire), unless you want to use an iron sparkler to fire off the thermite, similar to the way rail thermite is initiated.

 

You may want to try to source coarse copper oxide and aluminum granules for your base charge of thermite and see if you 1) get it to work, and 2) it flows properly to cast.

 

As to casting it, using a proper DRY graphite mold would likely be the best way to handle this (don't forget all the basic safety protocols you learned in your years as an electrician!). Be safe!

 

Good luck and have fun.

 

WSM

[Uarbor]

 

 

That sounds like silicon bronze. I'm a high voltage electrician, plus have also done a fair amount of cad welding in the past.

 

I'm not so certain you can't add silicon to the copper cast. Rail thermite (used for welding railroad rails in the field), has a mixture of materials in it to cast an alloy unique to their needs.

 

I believe alloys are possible with additions made to the basic Goldschmidt reaction.

 

The materials of the base charge are usually coarser to control the rate of the reaction (to make it flowable and not just a spray of molten metal), and use just a tiny amount of fine Al/CuO as a primary charge (first fire), unless you want to use an iron sparkler to fire off the thermite, similar to the way rail thermite is initiated.

 

You may want to try to source coarse copper oxide and aluminum granules for your base charge of thermite and see if you 1) get it to work, and 2) it flows properly to cast.

 

As to casting it, using a proper DRY graphite mold would likely be the best way to handle this (don't forget all the basic safety protocols you learned in your years as an electrician!). Be safe!

 

Good luck and have fun.

 

WSM

thanks I just so happen to have some silicon. I wish I still had my arc flash gear that would be perfect for this LOL

Check out how nice this comes out.

 

https://youtu.be/OFs1yKg6JvU

 

It's hard to find rough copper oxide everybody's always bragging about how fine it is when they're selling it. I think I'll give granulation a shot. Maybe granulating with dextrin will slow things down. It can't hurt to try I guess. I'm impressed with the amount of copper that get there must be added copper granules in that stuff.

Edited February 14, 2022 by Uarbor

[Richtee]

That welding is fucking COOL

Sorry... back to topic. I just hadda admire the video.

[WSM]

thanks I just so happen to have some silicon. I wish I still had my arc flash gear that would be perfect for this LOL

Check out how nice this comes out.

 

 

Yup! That's what I've done many times.

 

As seen in the video, the reaction is very fast and creates the hot liquid molten metal in less than a second.

 

What they show is a brand new graphite mold, doing the same thing with a well-used mold is a bit trickier and sometimes extra steps are required to keep the molten metal in the container until it cools enough to remove the mold. We used to use some kind of putty to fill imperfections in the graphite mold, if necessary.

 

Also, the split mold has to fit together PERFECTLY (NO gaps), or the hot metal (which has very low viscosity) will run out and create "interesting artwork" on the surface underneath the mold (very hazardous!).

 

I never waited 15 seconds for the metal to cool before removing the mold. It usually sets up enough in 2-3 seconds to remove the mold and only a few seconds more before removing the glass flux (with a sharp rap from a steel tool, screw driver or pliers [whatever you have handy]) from the top of the cast copper.

 

I forgot to mention the thin steel disk under the thermite. It keeps the thermite in the mold till the molten metal is formed (in microseconds) and then burns away and allows the flow into the mold below. In the trade, we nick-named the disk a "coin", but it's actually a thin, formed shallow cup in shape (as seen in the video).

 

One thought: Thinking about the flux, you may want to add some borax (sodium borate granules) to the thermite mixture to help control the reaction and help the molten copper stay shiny and un-tarnished. The glassy flux will be on the top of your cast copper and can be broken off easily with a hard metal object, after the cast metal is solidified (no need to wait for it to completely cool or the glass will be hard to totally remove).

 

Good luck and don't go cheap on your PPE. At a minimum, use good leather gloves, a somewhat darkened face shield, long sleeve cotton or wool shirt and trousers, closed toe leather shoes and an initiator that keeps you away from the process. Never stand above the reaction; all that high heat rises VERY fast and you don't want a face full. This is a hazardous process but can be done safely of you are careful.

 

WSM

[Uarbor]

 

 

Yup! That's what I've done many times.

 

As seen in the video, the reaction is very fast and creates the hot liquid molten metal in less than a second.

 

What they show is a brand new graphite mold, doing the same thing with a well-used mold is a bit trickier and sometimes extra steps are required to keep the molten metal in the container until it cools enough to remove the mold. We used to use some kind of putty to fill imperfections in the graphite mold, if necessary.

 

Also, the split mold has to fit together PERFECTLY (NO gaps), or the hot metal (which has very low viscosity) will run out and create "interesting artwork" on the surface underneath the mold (very hazardous!).

 

I never waited 15 seconds for the metal to cool before removing the mold. It usually sets up enough in 2-3 seconds to remove the mold and only a few seconds more before removing the glass flux (with a sharp rap from a steel tool, screw driver or pliers [whatever you have handy]) from the top of the cast copper.

 

I forgot to mention the thin steel disk under the thermite. It keeps the thermite in the mold till the molten metal is formed (in microseconds) and then burns away and allows the flow into the mold below. In the trade, we nick-named the disk a "coin", but it's actually a thin, formed shallow cup in shape (as seen in the video).

 

One thought: Thinking about the flux, you may want to add some borax (sodium borate granules) to the thermite mixture to help control the reaction and help the molten copper stay shiny and un-tarnished. The glassy flux will be on the top of your cast copper and can be broken off easily with a hard metal object, after the cast metal is solidified (no need to wait for it to completely cool or the glass will be hard to totally remove).

 

Good luck and don't go cheap on your PPE. At a minimum, use good leather gloves, a somewhat darkened face shield, long sleeve cotton or wool shirt and trousers, closed toe leather shoes and an initiator that keeps you away from the process. Never stand above the reaction; all that high heat rises VERY fast and you don't want a face full. This is a hazardous process but can be done safely of you are careful.

 

WSM

thanks for the info. I do in fact have borax I use it for flux when I do my Forge welding in blacksmithing I never thought about it slowing things down. That's a good idea

[WSM]

thanks for the info. I do in fact have borax I use it for flux when I do my Forge welding in blacksmithing I never thought about it slowing things down. That's a good idea

 

 

It may be slower, but it won't be slow! The reaction happens very fast and the metal solidifies in a few seconds.

 

The main purpose for the borax is to give a cleaner casting (see how shiny the cast copper in the video looks!).

 

WSM

[CountZero]

Red copper oxide thermite might be slower...

[Richtee]

 

 

Yup! That's what I've done many times.

 

 

OK..sooo why? What’s the application..bare copper in a ditch. I’m confused. Has to some strange grounding thing?? Curious. Obviously it’s not supplying current.

[WSM]

OK..sooo why? What’s the application..bare copper in a ditch. I’m confused. Has to some strange grounding thing?? Curious. Obviously it’s not supplying current.

 

 

In power stations, all metal is grounded, even the perimeter fencing. EMF is induced in metals (in power stations) by induction though the air, so grounding (and ground grids) are vital. A surprising (and dangerous) amount of voltage and current can be induced and get shunted into the ground grid.

 

The thermite casting of copper alloys is used to bond elements of the ground system into a complete and solid grid, without added resistances that mechanically bonded components would introduce.

 

The grounding of metal structures in power stations, plus separation of personnel from the grid by crushed coarse rock over it, are all for safety.

 

This discussion of Cad-Weld methods are an example of thermite copper casting, which is where this discussion originated.

 

WSM

[WSM]

Red copper oxide thermite might be slower...

 

Possibly, but how much? It may still be very fast, even with more copper and less oxygen that red copper oxide (Cu₂O) would offer.

 

WSM

[Richtee]

 

 

In power stations, all metal is grounded, even the perimeter fencing. EMF is induced in metals (in power stations) by induction though the air, so grounding (and ground grids) are vital. A surprising (and dangerous) amount of voltage and current can be induced and get shunted into the ground grid.

 

 

 

WSM

Thank you. I learned 2 things today A GOOD day!

 

On edit... Hmmm maybe I should wind a few big coils and hang ‘em on the fence of the local substation

Edited March 1, 2022 by Richtee

[WSM]

Thank you. I learned 2 things today A GOOD day!

On edit... Hmmm maybe I should wind a few big coils and hang ‘em on the fence of the local substation

 

 

If it's a chain link fence, it probably won't work (think Faraday cage). Some folks thought they'd cheat the system by putting coils on the ground under transmission towers. It worked BUT the power companies monitor their system so carefully, they were able to detect even that small power loss and eventually catch the thieves and prosecute them. They don't mess around!

 

WSM

[WSM]

Thank you. I learned 2 things today A GOOD day!

On edit... Hmmm maybe I should wind a few big coils and hang ‘em on the fence of the local substation

 

 

I believe an artist (with approval of the power company) demonstrated the field effect of transmission lines by sticking vertically in the ground, a field of 4 foot fluorescent tubes, and photographing them at night. They glowed with varied intensity depending on their proximity to the lines overhead. Very interesting!

 

The photo might be available on You Tube.

 

WSM

[Richtee]

 

 

If it's a chain link fence, it probably won't work (think Faraday cage). Some folks thought they'd cheat the system by putting coils on the ground under transmission towers. It worked BUT the power companies monitor their system so carefully, they were able to detect even that small power loss and eventually catch the thieves and prosecute them. They don't mess around!

 

WSM

Dayumm...