sodium metaborate instead of borax

[Greenhornet_au]

I have not melted gold before, but could it be that your torch heat is not high enough and the crucible side is too cool for pouring,
as the gold touches the higher side it cools on the surface.

Casting lead has similar issues.

 

[nucopia]

That seems to be what the problem is Dave ..the small crucible is ok with a small amount of gold (couple of grams ) because it can melt the gold and form a small button no need to pour it etc
but with a larger amount of gold, it just cant get and stay hot enough to keep the gold liquide and pour it into the mold ..
Its taken us 4 years to collect that 16 grams and I am happy to now have a decent blob of gold to hold onto and until we can collect more I wont need to melt it again :Y:

 

[davsgold]

That seems to be what the problem is Dave ..the small crucible is ok with a small amount of gold (couple of grams ) because it can melt the gold and form a small button no need to pour it etc
but with a larger amount of gold, it just cant get and stay hot enough to keep the gold liquide and pour it into the mold ..
Its taken us 4 years to collect that 16 grams and I am happy to now have a decent blob of gold to hold onto and until we can collect more I wont need to melt it again :Y:

All good Bryan, I know it's great when you can get all those small nuggets and fines melted together into one piece, well done mate. Just gotta keep at it and accumulate more. erfect:

cheers dave

 

[jon_m]

Copied your set up Dave, and melted my first gold.

Thanks again for your video and explanations.

Maybe with one burner I should have turned the crucible - looks like I started to melt it. Only put a couple of grams in for first go and had trouble deciding when the gold had melted, so burner was on for 12 to 13 minutes! ... and torch should have been further back??

Also appears I added too much borax, Had an extra blob of black come out, aside form that on the button. Dipped it into HCl from the mould but was it just too much borax that stopped it all from separating?

 

[nucopia]

Jon_m
Is that a hebel block you are using ?

 

[davsgold]

G'day jon_m

Your on the right track mate, I do think you need two torches and keep them back out a bit from the graphite crucible, I have the nozzles of the torches only about half way into the hebel block.

And yes you don't need very much borax, first use of a new crucible I put maybe 1/4 teaspoon in with 65grams of cleanish nuggets, the cleaner the gold (acid cleaned) the less borax I use, and because there is remaining flux/borax lining the crucible for the next times it is used I put a lot less in.

The graphite crucibles do wear away from the heat anyway but I get at least twenty or more uses from one before it gets to thin, and I just crush it and pan of the remaining fine gold that is stuck in the glass flux/borax which is in the old crucible.

cheers dave

 

[jon_m]

Warning - Restricted hazardous chemicals/dangerous goods use or discussion isn't endorsed by Forum Management. Individuals using any hazardous chemicals/dangerous goods do so at their own risk/s and need to ensure their own legislative compliance.

Hi Nucopia, yes hebel block. Cut it very easily with a bow saw, and bored the hole with an old 55mm bit. I noticed your button looks quite golden compared to my mine. Guessing there's quite an amount of silver in mine. Wish someone would invent some alchemy for dummies.

Dave, thanks for the confirmation. Looking forward to doing some cleaner melts now. And a heap of mercury arrived yesterday. Way way more than I need! So have to get a retort underway - but if that' a story, then its one for another thread I guess.

Appreciate your help greatly.

 

[nucopia]

Did another melt of some fine gold and a couple of small nuggets yesterday.
I think I used to much borax which just created a blob of sticky crap in the bottom of the crucible..
Put the blob in acid over night and now its just oop:

After it dries out in the sun for a while , its going into a small vial.
:/

 

[davsgold]

when the glassy blob is dry, put it back in the dolly pot and crush it up again and pan off, get the gold and add the gold next time you melt.

when doing the job and with gold and borax I just use about 1/4 teaspoon at most to 65grams of clean gold/nuggets

if melting in a porcelain type dish whenyou have the gold and borax all molten just use a graphite rod, or (welding rod) as it is starting to cool push the glass around a bit and away from the gold, keep using the flame when necessary and the glass flux will stick to the rod and leave the gold behind.

Once again keep the glass flux cool it down and recrush it as there will be fine particles of gold in it.

The easiest and best method is a graphite crucible (small cylindrical tube type) and put it in a furnace till all melted and then tip into a graphite mould.

cheers dave

 

[nucopia]

Thanks Dave
I have kept everything as you suggested and will likely crush it up and pan it off later..
I think after Chrismas I will order a grafite crucible and get some hebel block from bunnings ..
Only thing i need then, is more gold to smelt
Heading out on Boxing day for a couple of weeks in Wellington to finish the house reno and a few days here and there at Ophir or Stuart Town ..

 

[davsgold]

Have a great Christmas nucopia and we may catch up again it the great outdoors somewhere. ickshovel:

cheers dave