Assay Process

[Shane1985]

Hi guys, all well I hope.

I am a noob here and just wanted to ask if someone could shed light on the assay process.

I am getting in to pouring bars but want to follow legislation and do things right as I want to sell my bars etc.

I have been reading a lot on Assay but I can’t find what the actual process is.

Could someone shed some light please?

Will I need to send all my bars to Assay where Assay will do all their checks and then stamp the bar with hallmarks and my initials?

How do I get in to a position to stamp or laser my own bars? Is that even possible?

Thanks all, I hope you can help!

Cheers

Shane

 

 

[Rll1288]

HI, @BackyardBullion has a wealth of knowledge on the assay process and the value it brings and there is a video interview with the Head of the Edinburgh Assay office coming out on his YouTube site soon. When you say "Stamp or Laser" your own bars... do you mean with just weight/ date etc. or actual Hallmarks? The later you can't do as that's illegal and as said, Mr BYB is a great source on what it entails etc.

[BackyardBullion]

Scheduling issues are making finding a time to sit down and film said interview a little harder than expected 😉

Hopefully later this month anyway.

Bottom like, only an assay office can assay and put hallmarks on a piece. You can stamp your own silver with whatever else you like and even use your own laser engraver if you have it.

The basic process is as you have said though, you make a product, send it to the assay office, they test it and stamp it and send it back and then job done.

[Shane1985]

Thanks a lot gents, I appreciate you getting back to me!   Right then, I better get registering with Assay and get making!!  Illl keep you all posted on my first bar  

[Rll1288]

Do check out @BackyardBullion YouTube channel... wealth of knowledge on pouring

[Shane1985]

Thanks buddy, I have been watching most of the morning. Love it! 
 

 

[Pete]

It would still be interesting to know the Assay process from a technical stand point.
Do they make a specific gravity test on each piece and maybe use an XRF apparatus ( would this verify 100% or just the first mm of thickness ? )
Would an assay office be able to verify a 25kg gold bar, for example, containing a tungsten core ?

[SilverAngel]

On some pieces they take a sample of the PM and verify that way. As you mentioned an XRF is good for first few mm but on larger, deeper pieces they use other means

[sovereignsteve]

2 hours ago, Pete said:

It would still be interesting to know the Assay process from a technical stand point.

I think the gold standard, if you'll pardon the pun, is cupellation, which has been used for centuries.

[Pete]

20 hours ago, SilverAngelPouring said:

On some pieces they take a sample of the PM and verify that way. As you mentioned an XRF is good for first few mm but on larger, deeper pieces they use other means

Do you know for sure the "other means" and are they secret / proprietary perhaps ?
What other means exist for verifying a block of any metal which is thick enough to block gamma ( X-ray ) transmission ?
Any spectroscopic analysis involves ablation of the surface ( microscopic area ) and will be very restricted in penetration depth.
Ultrasonic testing will only pick up cracks and changes in density but I don't know the density difference threshold to show up.

[sovereignsteve]

1 hour ago, Pete said:

What other means exist for verifying a block of any metal which is thick enough to block gamma ( X-ray ) transmission ?

The only way they have is to core drill samples.

[Pete]

21 minutes ago, sovereignsteve said:

The only way they have is to core drill samples.

So as far as we know there is no "non-destructive test" to determine purity ?

[SilverAngel]

1 hour ago, Pete said:

So as far as we know there is no "non-destructive test" to determine purity ?

To be honest the hole is tiny and you can have them repair it (for a cost), for me though its not a blocker form adding that little extra piece of quality 🙂

[sovereignsteve]

3 hours ago, Pete said:

So as far as we know there is no "non-destructive test" to determine purity ?

Not for a thick piece of metal. You may be able to see a different metallic core by some x-ray type of inspection, and thus reject the sample, but that's not quite the same.

[sixgun]

On 13/02/2021 at 02:44, Shane1985 said:

I am a noob here and just wanted to ask if someone could shed light on the assay process.

I am getting in to pouring bars but want to follow legislation and do things right as I want to sell my bars etc.

Cheers Shane

i get the impression what you are asking is 'When do i need to get my silver work hallmarked?'
I don't think you are really that interested in the 'assay process', how it is done, whether a piece is drilled and so on.

If you are pouring 'bullion' in any shape or size, it does not need to be hallmarked - you can put your own marks on - 999 Silver - Your logo and so on.
If you work is more than a lump of metal then and is going to be sold in the UK, then it has to be hallmarked by an Assay Office.

So something like this from Silver Towne is bullion - it is not being bought for some sort of aesthetic appeal.

Whereas something like this i just got from Silver Angel Pouring is clearly an art piece - its value is in the design and beauty of the piece.

 

So where does your work lie in the spectrum. If it is simple bars, bought for the silver content then you don't need to worry about hallmarking - if they have nice designs, ripples, antiquing and the like - so that people who will buy then will buy then for those features, then you should start investigating a hallmark.