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Old 11-08-2015, 09:30 PM
Dwane Dwane is offline
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Join Date: Aug 2015
Posts: 306
Black iron

Hi wrtner,
A replacement for the low oxygen welding rods recommended by John Bedini is soft iron wire. This goes under many names, tie wire, baling wire black wire and so it goes. It is soft in as much as it is malleable and easily bent and twisted. It has become somewhat a specialised product. Most tie wires now available are mild steel zinc or galvanised coated. The advantage of using these would be their diameter options. Smaller diameter closer lamination effect for a circular coil core.

Commercially I have found that the lowest carbon steel available is 1004 and is coloured black end. I think I am correct in stating that most mild steel are around 1015 which is carbon between 2% and 3%. The Carbon affects the remanance.

To make black iron from mild steel it is necessary to anneal the mild steel in a furnace of some sort. I am lucky enough to have a kiln. The process is simple. The mild steel is heated through to cherry red at approximately 1000 centigrade, and then allowed to cool slowly. When removed from the kiln it will be coated with a layer of Black residue. This is very brittle and falls away easily. Beneath this carbon residue the mild steel now is coloured Black.

This process has effectively leached the majority of carbon from the mild steel and is classified as soft Iron. It's magnetic properties are now more suitable for high speed switching.

I also chose to go this route for my prototype as by drilling and tapping the end of the bolt, I am able to securely fix the coils to a backing plate. Using bundled wire make secure fixing more difficult.

Hope this helps.

I am putting my FEG back together to day. I have a bit of circuitry to design for the controller switching. Here I think that I have to discover the charge and discharge parameters for the pulsing back to the battery. From my perspective there are two discharge rates. 1) A battery boost and 2) Lenz boost to the coils. This is where all the headaches arrive!

cheers

Dwane
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