Non-Chemical Oxyhydrogen torch (HHO) for melting gold

[KreAture]

I have been fiddling with a kiln and different burners to melt my small tests of gold and have had difficulty either getting enough gas flow or getting the combustion right to achieve proper temperatures. My kiln manages 800c and I can get to 900c with manual gas torch in a small crucible.
Being a bit fed up I decided to make a HHO cell (yes with mixed gas output) and a bubbler to arrest any flashback. Then I simply ordered a small jewelers torch from aliexpress with a flashback arrestor in the handle and 4 nozzles from 0.3 to 0.6mm plus a huge 1.5mm one. This torch was so cheap that I could have bnought 10 of them with the money I spent on gas torches for propane/butane and MAPP etc.

I tested the built in arrestor and it seems to work well with the flows I can provide at the moment. (The lower the flow, the higher the chance of flashback.) My little cell only runs around 192w (12v 16a) and it produces approx 12l/h. This is below recommended flows for these nozzles but seems fine. At half power I get flashbacks stopped in the torch with the 0.6mm nozzle but the smaller nozzles seem to have enough flow.

The visible flame (in dark room) is only about 5mm long but it seems to do the job on tiny beads of gold.

I tested it on a crucible I had left over with some gold powder stuck in the borax.
With no preheating of the crucible and just sticking the torch to the gold dust at 1-2mm distance it immediately turned into beads. I was amazed at how easy this was compared to the kiln.

Going to increase my HHO output and do a few more tests on this before my next proper melt but this was fun.
I really wanted to share this as it was such a joy to get it working.

I will post some pictures later. Maybe even do a video under the microscope of the effect the flame has on some gold dust. It is just so lovely to see.

 

[KreAture]

Here's a picture of the tiny flame.

I tested remelting my little bead of gold to form it better and include the tiny 8mg bead and some dust in the crucible. Worked very easily and took around 5 seconds!
The bead was molden for a fraction of a second after I removed the flame and blinked to solid and I could pick it out of the borax and drop it in water.
Weight was 123mg. (I got myself a 20g range, 1mg resolution scale for this. Here in Norway I doubt I will ever see an ounce nugget...)

 

[shmandi]

I think you should increase l/min of HHO for anything more serious.
What kind of cell do you use, what is your power supply and what do you mix water with?

 

[rickbb]

I've been looking at HHO torch systems and you can get a complete 95LH setup for $200 on Amazon.

 

[KreAture]

shamandi:
Of course I need to increase lph. This was just what I had available to do a quick test.
I was also interested in actually getting info out there on how low flow you can get away with on these nozzles before you get flashbacks. I had been under the impression that I needed around 80 lph for the 0.6mm nozzle but with a good flashback arrester (as you have a higher chance of experiencing a flashback) and just a few 10's of lph you can get tiny work done.

The cell I tested with had 17 plates with 3mm spacing. I had a 12v supply available so I used that and adjusted the water with sodium hydroxide to an amperage I was ok with. In the video it runs, as I said, at 192w.
The voltage potential is rather too high for the gap so I kept the lye down to a minimum. This appears to work ok for a test cell.

rickbb:
Wow, that sounds interesting! I wonder what the shipping is to my corner of this, the frozen hellhole or planet of Hoth.