Dropping Gold using Stump Out (sodium metabisulfite)

[butcher]

Use a copper buss bar, if gold is in solution copper will cement it out, leaving your solution in good shape for another batch.

Read Hoke's book.

She teaches you how to make a gold test standard solution. you can use to test your stannous chloride solution with.

Did I mention read Hoke's yet?

 

[Richard NL]

"just put a few pieces of solder in the container"
"storing it in a dropping bottle that is kept closed tightly"

Wrong combination!

Pressure will build up from the hydrogen gas.
The first thing that will expand is the rubber bulb, till the point it will rupture.
Blowing almost all the Stannous Chloride out of the glass pipette dropper bottle.

It was a real mess and a whole lot of cleaning.
Everything covered in Stannous Chloride

 

[goldsilverpro]

"just put a few pieces of solder in the container"
"storing it in a dropping bottle that is kept closed tightly"

Wrong combination!

Pressure will build up from the hydrogen gas.
The first thing that will expand is the rubber bulb, till the point it will rupture.
Blowing almost all the Stannous Chloride out of the glass pipette dropper bottle.

It was a real mess and a whole lot of cleaning.
Everything covered in Stannous Chloride

The 1st time I made sannous chloride, I put it in a bottle with a rubber bulb/eyedropper, just like you. Same thing happened except I caught it before the bulb popped. It had expanded to about 2" in diameter.

When Hoke says, "dropping bottle", she's not talking about one with a rubber bulb. She's talking about a glass bottle with a fritted glass stopper. The stopper is turned to a certain position that allows drops to come out, one by one, when the bottle is tilted. Hoke wrote that book 76 years ago. When I first started, these bottles were very common. They still make them. The last touchstone kit I bought had 4 empty glass dropping bottles, with instructions how to make the acids.

http://www.coleparmer.com/Product/Clear_glass_dropping_bottle_50_mL_Pack_of_6/EW-08923-04

 

[Richard NL]

I hope that we can reduce this mistake by these posts!

The clear glass dropping bottles in the link you gave, looks really nice.
But a bottle with a rubber bulb/eyedropper can be purchased for about +-€1,25 (7 minute walk to the store)
I think that a newbie has a great chance to make the same mistake.

 

[upcyclist]

I use the polyethylene refillable dropper bottles--basically, you squeeze the body instead of a dropper bulb. In my experience, acids eat those bulbs like, well, acids eat them

Also, with these, you can leave the cap on loose, it still protects the contents (contaminants would have to travel uphill to get to the opening in the bottle).

I got mine from amazon, but they're not too hard to find elsewhere.

--Eric

 

[FrugalRefiner]

Cheaper on eBay.

Dave