Non-Chemical problems pouring my gold

[Jkessans]

Everytime I pour my gold bars, the top always turns black, but the bottom and sides of ingot looks good. Any suggestions?

 

[snoman701]

You still have silver or other base metals in the bar and they are oxidizing. You can add a little borax and it will help.


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[anachronism]

As Sno said.

That given I would take the approach that you need to clean your gold better before melting it.

 

[grainsofgold]

Keep the torch on the top of the bar during and after your pour - you do not want the flame to be on the blue side more yellow- after the bar solidifies take the torch off and then you might want to pickle the bar in a heated pickle solution which will get the crud off-

 

[anachronism]

Keep the torch on the top of the bar during and after your pour - you do not want the flame to be on the blue side more yellow- after the bar solidifies take the torch off and then you might want to pickle the bar in a heated pickle solution which will get the crud off-

Sorry but this isn't right.

 

[grainsofgold]

I use a propane and O2 torch - never had an issue=

But always looking to learn more-

In melting silver I know that added o2 is not a great thing-

 

[snoman701]

I use a propane and O2 torch - never had an issue=

But always looking to learn more-

In melting silver I know that added o2 is not a great thing-

With a reducing flame you won't get the ugly oxidation scaling if there's silver there...and it doesn't take much silver to make it ugly. 98-99% will be UGLY if you hit it with heavy oxidation.

 

[Jkessans]

I just recieved my assay, it was 99.1....without doing an AR treatment. Thanks for your help on the torch, snoman