# Front and back



## Jmk88 (Aug 12, 2020)

Hello,

Probably one for nick or Lou.

I have been offered a large amount of front and back jewellery from an antiques man who took them as part of a bulk load; he has no interest whatsoever in jewellery and is offering me nearly a kilo at what he says is 15% of content.

I’ve been told to snap his hand off? 

Any thoughts? What is front and back? What does it mean? 

Thanks in advance.


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## Jmk88 (Aug 12, 2020)

Anyone....?


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## butcher (Aug 12, 2020)

Front and back of earings? I do not know, but it might be a good idea to find out before putting much money down to purchase them...
Ask the jeweler to get a sample, or show you what he has...


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## Johnny5 (Aug 12, 2020)

If it's too good to be true, it probably is.


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## jarlowski1 (Aug 12, 2020)

Johnny5 said:


> If it's too good to be true, it probably is.



Truer words have never been spoken


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## philddreamer (Aug 12, 2020)

I did a quick search on line, and all I found is earrings that have art in the front and the rear of the ear lobe. 
Same with necklaces... 
for an example of an earring:


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## Jmk88 (Aug 12, 2020)

Thanks all! 

I don’t think it’s a “too good to be true” scenario.

I have known the man and wife selling since I was 7/8. He is saying i can make some really really good money.... he’s talking a mark up of about 10/11k from a 6k payment.

He is a jeweller and is someone I would go to for advice. I just wondered whether anyone else has done similar.


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## nickvc (Aug 13, 2020)

Front and back is another description for gold filled or rolled gold, it’s hard to value as much is very worn but I wouldn’t want to pay more than the value of 1/20 9 carat with a profit added in.
You are been told it’s solid not filled hence the value he’s claiming which is nearly spot for 9 carat the only one making money here is him, you would lose £5000 not make 10 / 11 k.


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## Jmk88 (Aug 13, 2020)

Thanks Nick! 

Someone has said something similar... except that large proportions of the items are in face solid, with clasps and such being high quality filled. 

They have said that general rule of thumb is to go by about 50% of item weight and divide that by 9ct. 

If that is the case then my calculations make the chap spot on. Plus he knows there’s no where to hide so to speak so I can’t see he’s trying to scam me. 

In any case I’m taking 100 grams off him today which I have agreed to pay full asking price for if it is what he says. I’m going to process it all in his workshop tomorrow in front of him. 

If I get what I am told I should, I will purchase the rest.


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## nickvc (Aug 13, 2020)

The maths for that calculation is way off in my opinion but for your sake I hope I’m wrong, please give the results when you have done the sample batch as it may help others who are offered similar items.


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## Jmk88 (Aug 13, 2020)

Cheers Nick.

I’m heading over there shortly to sort 100g from the pile. 

Will 100% post results.


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## jarlowski1 (Aug 13, 2020)

Glad that you are able to take a small sample. Looking forward for the results.


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## kurtak (Aug 15, 2020)

Jmk88 said:


> In any case I’m taking 100 grams off him today which I have agreed to pay full asking price for if it is what he says. I’m going to process it all in his workshop tomorrow in front of him.





> I’m heading over there shortly to sort 100g from the pile.



So how did your test go :?: 

Kurt


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## Jmk88 (Aug 15, 2020)

I have just dropped it all and dried.

I have 17.3 grams from 100 grams of the material which makes the chap spot on.

This is however the first refine and I anticipate losing maybe 0.2/3 on the second. As I normally do.

I will be purchasing the rest Monday.


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## Jmk88 (Aug 16, 2020)

Second drop.

I’m going to collect a new blow torch shortly so will stick this in the oven for an hour (100c for anyone interested) and will post my melt later on this afternoon or evening.

The pictures are like Salma Hayeks dance from start to finish in dusk till dawn... I’m confused about which process I enjoy watching the most.

:roll:


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## Jmk88 (Aug 16, 2020)

And yes... that’s a picture of my wife. 

Not intended. 

:lol:


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## kurtak (Aug 16, 2020)

Jmk88 said:


> I have just dropped it all and dried.
> 
> I have 17.3 grams from 100 grams of the material which makes the chap spot on.



8) Glad to hear the test run went as expected/hoped for :!: :mrgreen: 

Kurt


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## Jmk88 (Aug 16, 2020)

Thanks Kurt! Much appreciated.

I will post final results.


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## Jmk88 (Aug 16, 2020)

Well.... here it is.

Not very happy with the outcome this is the second refine! 

I must have contaminated it with something.

It’s going to go back in next weekend I’m too tired to do anymore today. 

But all in all... success. I think after contamination removal it’s going to be close to 17 grams on the dot.


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## Yggdrasil (Aug 16, 2020)

I'm a bit confused of the color of your liquid.
It do not seem clear, is it silver chloride in it?
It should anyway be filtered so it is completely clear. before dropping the gold.
Nice size button anyway :mrgreen:


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## Jmk88 (Aug 16, 2020)

I don’t know I was struggling to filter it properly for some reason. I just couldn’t get it clear. 

I’m not sure I don’t think silver chloride I think it’s filter paper. 

Yes I don’t think the colour suggests any less than 95% but I will clean it up next week.


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## kurtak (Aug 16, 2020)

Yggdrasil said:


> is it silver chloride in it?



Or stannic tin ?



> I think it’s filter paper



for sure not that --- it is metal salts - as in silver chloride - or stannic tin - or ???

The metal salts are in the form of colloids with are ULTRA fine particles - so fine that that they stay in suspension & tend to go through filters

if you don't eliminate then before dropping your gold they will just keep following you from one refine to the next

One way to eliminate them is to add a flocculant &/or coagulant to the solution before filtering

Edit to add; - with an acidic solution you need to use an organic polymer flocculant --- it takes very little & requires continuous stirring (which is where a magnetic stirrer hot plate comes in handy)

"sometimes" filtering with a charman plug filter will work - or "maybe" a wick filter

Did you put the first drop through the "proper" washes before dissolving the gold for the second refine ?

Bottom line - if you drop gold from a dirty solution (that has metal colloids) you ARE going to get a dirty drop - they NEED to be eliminated BEFORE the drop - or they will just keep following you gold drops

How you go about eliminating them depends somewhat on the kind of metal salt colloid is causing the problem :!: 

Kurt


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## Jmk88 (Aug 16, 2020)

Thanks for the tip Kurt. Again, much appreciated.

Some more bed time reading! I am not so sure that it was tin as I magnet test every piece after I’ve cut it up. 

I think silver chloride which would explain the odd colour on one side. Having looked at the filter I think it definitely is. 

I have watman ultra fine filters but I find they take ages to drain. I use them mainly for my waste process.


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## Jmk88 (Aug 16, 2020)

And sorry Kurt, no I don’t ever wash my first drop I just immediately put it back into solution.

I didn’t wash the second drop properly either now I think about it. I just rinsed with boiling water not hcl :roll: 

I have a lot on this weekend so was in and out of the workshop.

Plus I haven’t had any time off since Xmas so im beginning to fatigue a little bit in general.

I need some down time.


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## Yggdrasil (Aug 16, 2020)

A magnet won't do much to Tin (Sn).
Its not magnetic as far as I know, tin roofs or tin cans on the other hand....
At least not ferromagnetic, it is weakly paramegnetic, which won't be noticed in minute amounts.


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## Jmk88 (Aug 16, 2020)

tin is very magnetic and I have a Small industrial magnet. It can pick up even the smallest bit of tin.

Tin is super magnetic to my magnet.


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## Jmk88 (Aug 16, 2020)

Look...

Sometimes clasps or replaced closers on the jewellery I refine have tin. They literally fly up when I hover the magnet over and they then burn instantly with propane.


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## Jmk88 (Aug 16, 2020)

I can lift it...


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## jarlowski1 (Aug 16, 2020)

You can usually find pieces that have tin if you are able to incinerate the material first. Tin melts around 230c. With jewelry I find it to be very beneficial to incinerate it first since there is so much organics in and on them (dead skin, grease, oil, hair, perfume, soaps ect.) . When you incinerate the jewelry you can isolate the pieces that start melt or show signs of something melting at these lower temperatures.


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## Jmk88 (Aug 16, 2020)

Yes I agree... that’s what else I was going to say. I incinerate in a dish first so I’m certain it’s not tin.

My sister just pointed out to me I’m very wrong and that food cans are actually steel based... :roll: 

She said tin is not magnetic. Now I’m super confused as when I have like small bracelet chains they do react with my magnet then burn at super low temperatures....

Can anyone explain this? I thought this was tin?


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## Yggdrasil (Aug 16, 2020)

Sorry man, what you show is tinned steel so called a tin can.
That is Steel(Iron, Ferrum) covered with a thin layer of Tin(Sn).
It has per se nothing to do with Stannum (Tin)(Sn)
Tin metal (Sn) is weakly paramagnetic.
Pure Tin, may be picked with a strong Neodymium magnet, maybe....
But the amount used to solder jewellery will not be noticable with a magnet.
The clasps may be made of non noble metals because of the stresses it are subjected to and price of course.


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## Jmk88 (Aug 17, 2020)

Thank you! 

Understood. Yes that’s what she immediately said. She is about to start a PhD in chemistry.

We’re cut from very different cloths.


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## kurtak (Aug 17, 2020)

Jmk88 said:


> I incinerate in a dish first so I’m certain it’s not tin.



incineration does not eliminate tin - if there is tin involved such as solder joints or (gold plated) clasps that are made of tin the tin will melt due to its low melt point - though tin has a low melt temp it has a very high boiling point which is 2,602 C (4,716 F) - in other words it has to get even hotter then that before it burns up (vaporizes)

Tin is a refiners nightmare due to its turning to stannic tin when nitric is used (whether straight nitric or nitric in AR) with the stannic tin being the problem I explained in my other post (staying in suspension &/or passing though even the finest filters)

Once you have it - it is very difficult to get rid of - it likes to haunt you (likes to keep following your gold) it needs to be eliminated one way or another --- doing a (simple) HCl (hot) wash will not get rid of it

Though tin (the metal) dissolves in HCL --- stannic tin does not

When dealing with gold plated - gold filled & even "low" karat material you are likely to run into tin

Besides solder, clasps etc. - you will run into it in the base metal alloys that the gold plating &/or gold filled is on - base metals of brass &/or bronze are common - some brasses can run between 1 - 5 % tin & bronzes can run as high as 5 - 15% tin (phosphor bronze being a common one that runs at 15% tin)

When you dissolve base metals that are alloyed with tin - & you dissolve those base metals with AR - due to the nitric in the AR - the result WILL be stannic tin - which then becomes the problem(s) already explained

It needs to be eliminated - or it will just keep following your gold

There are a number of ways to get rid of the (stannic) tin - which I don't have time right now to explain --- however - the normal water/HCl washes will not get rid of it

Though I can not say for sure - I am betting you have a stannic tin problem - not a silver chloride problem

Kurt


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## Jmk88 (Aug 17, 2020)

Hi Kurt,

I would appreciate any pointers on how to remove any tin prior to recovery.

Kind Regards,


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## Jmk88 (Aug 17, 2020)

Kurt,

Another question and some more info to help you out.

Would stannic not have dissolved in AR? 

When I ran my recovery... there was purple mud which I have assumed to be gold nano particles. Other than this.. my recovery solution was completely clear. 

You have me thinking now... the cloud did only appear after I had formed my AR which I assumed to be silver contamination not tin.


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## Yggdrasil (Aug 17, 2020)

Stannic tin as in Stannic acid, Sn hydoxide, Sn2O4 formes when tin and Nitric reacts.
That is why we try to remove as much tin as possible prior to the use of nitric/AR.
Or if it is foils or powder just skip the nitric completely.


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## Jmk88 (Aug 17, 2020)

Do you think the purple colour was stannic? 

I’m worrying now I’ve lost values.

I think I may have and Kurt is spot on. Would this explain the purple colouring of the past during my recovery?


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## Yggdrasil (Aug 17, 2020)

I actually have a couple of bottles with purple solution sitting on a shelf.
The color was so nice that I took care of them.
Only later, I realized that it might be a variety of a dilute stannous test.
The amount of gold in ther*e* is so small I haven't made any plans for it yet.

Edited spelling error


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## Jmk88 (Aug 17, 2020)

Thank you! That’s put my mind at ease...

I was thinking that based on my Calculations I didn’t lose much... I find I’m always slightly under but I always allow 10% with filled items for wear.


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## kurtak (Aug 18, 2020)

Jmk88

During the (work) week it is hard for me to post much due to having a day job - plus this time of the year deer & elk hunting season is coming up so I spend my week ends out in the woods scouting for the up coming hunting seasons - so my time to post much is limited

That said & as I said - tin is a gold refiners nightmare - if not properly dealt with - & that depends on when/where it is encountered during refining



> I would appreciate any pointers on how to remove any tin prior to recovery.



Because of the "many" possibilities of when/where you will encounter tin in refining you are asking me to write a book - which I don't have time for

However - that said - if the tin is in the form of "tin metal" - such as tin solder you get rid of it by "first" dissolving it with "just" HCl - on the other hand if the tin is part of a base metal alloy (like brass or bronze) HCl alone wont solve the problem 



> Would stannic not have dissolved in AR?



NO :!: --- tin in AR does not get rid of stannic (tin) --- it "creates" stannic tin :!: 

that is all I have time for today - I will "try" to post more tomorrow

Kurt


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