Metal Density Testing Method

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Re: Metal Density Testing Method

Post by keg83 » Mon Jan 28, 2013 2:37 pm

this really is a useful way of determining what grade gold ...etc of finds really are .Ive just bought some jewellers scales and I have already tested many of my finds using this method . A very big thankyou for posting this article. ::g ::g ::g


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Re: Metal Density Testing Method

Post by chesters4 » Mon Jan 28, 2013 2:50 pm

Whats the density of lead?
We have a broken hallmarked ring that is hollow that contains lead ,i presume to bulk up the weight
So i presume the test only works for solid metal ,mind you it would pass the scratch test to as the gold itself is thick

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Re: Metal Density Testing Method

Post by Fusion » Mon Jan 28, 2013 3:59 pm

The density of lead is 11.34 grams per centimetre cubed.

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Re: Metal Density Testing Method

Post by kpjuk » Mon Apr 22, 2013 7:41 am

I found this a great post, and went and bought myself some scales to check my finds :) I also found the table of Metal Densities below that may be of some use. I have highlighted some of the more common materials. Remember for an alloy or mix of two metals, the density value will be somewhere between the lowest and highest of the two density values, so for example a Nickel / Silver mix, would be somewhere between 8.9 (pure Nickel) and 10.5 (pure Silver). Don't therefore assume if the density is 9.01 that your material must be copper!
Density Table.jpg
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Re: Metal Density Testing Method

Post by MetalGuru » Fri Apr 26, 2013 10:50 pm

The boss wrote:Neil and Julie,if I'm wrong but you can tell me lol but I think it started when an old scientist sat in a bath n wondered why the water rises,he then filled a measuring cylinder n added different object to the same amount of water and then come up with a mass equasion which would of evolved into this density equation lol I think that's right any how lol
Absolutly correct. The scientist was Archimedes, who jumped out of his bath shouting eureka, which means, 'I've found it'.

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Re: Metal Density Testing Method

Post by PONK » Mon Jul 01, 2013 8:20 pm

amazing ::g will be using this test. cheers for posting barny
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Re: Metal Density Testing Method

Post by Emrys » Sat Jul 06, 2013 9:12 pm

when i get some gold tommorow i will be testing this =)) =))
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Re: Metal Density Testing Method

Post by Gary Huston » Mon Jul 08, 2013 2:49 pm

That's a really helpful method for the good stuff. Unfortunately we don't always get the goodies so
I have listed a few of the not so good so if your numbers don't match the precious you have an idea what it might be!

Aluminium: 2.70
Zinc : 7.14
Iron: 7.87
Tin: 7.29
Copper: 8.93
Lead: 11.36
Cartridge brass: 8.50
Brass: 8.40
Titanium: 4.51

Some of the numbers vary slightly from site to site but should be pretty accurate.
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Re: Metal Density Testing Method

Post by yellow » Fri Sep 13, 2013 10:13 pm

Hi all.... :D

I'd read this topic some time back when it first got posted,then also flicked through it again a few weeks ago.
I've been beach detecting again a few times,and found some gold,or not gold rings as it may be and decided to order a set of digital scales to give this a try,as I found it a very interesting method.

Three small rings had a density of around 9.0 so I guess a brass/copper make up maybe..either way not gold,but one I found which was the main part of a signet ring weighing in at over 3.5 Grammes,turned out to be 9 carat..
I'd like to say thanks for the very informative post,along with the little snippets added by other users,as this method is accurate and well worth buying a set of digital scales for.
It also gives us detectorists something to do whilst bored =)) ,along with identifying any precious metals found.
So a big thumbs up from me ::g

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Re: Metal Density Testing Method

Post by mikengermany » Wed Dec 11, 2013 11:05 am

This is a great aid - but still have a question - does anyone have a list of what are averages for various coin groups? I have a little celtic coin that seems really heavy - weighs in at 1.78 grams, and according to this test is 8.9. But thats about the number for copper and this is anything but copper - unless its a silver / copper mix since it still has it's shine. Just curious. but really appreciate this simple process.

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Re: Metal Density Testing Method

Post by Nojo1972 » Wed Mar 02, 2016 9:56 pm

Littleboot put me on to this, I'll be getting some scales soon. Thanks for a great and easy to understand post. Well done
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Re: Metal Density Testing Method

Post by Danzigman » Thu Mar 03, 2016 8:25 am

Nojo1972 wrote:Littleboot put me on to this, I'll be getting some scales soon. Thanks for a great and easy to understand post. Well done
Hi Nojo.. Scales here - page one 6 post down.. - http://www.metaldetectingforum.co.uk/vi ... lit=scales" onclick="window.open(this.href);return false;
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Re: Metal Density Testing Method

Post by Dave8472 » Thu Mar 03, 2016 11:41 am

Think he meant weighing scales John ::g

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Re: Metal Density Testing Method

Post by Danzigman » Thu Mar 03, 2016 12:01 pm

Dave8472 wrote:Think he meant weighing sales John ::g

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Weighing Sales or Weighing Scales Dave.. Language is a difficult size.. Any way.. Both is handy to have. And for sure He mean eletronical weight. Personally I have the Tomopol S 050.. http://www.kaparts.co.uk/pid/139245" onclick="window.open(this.href);return false; ::g
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Re: Metal Density Testing Method

Post by Dave8472 » Thu Mar 03, 2016 2:19 pm

I didn't help with a typo John, sorry mate meant scales :))

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Re: Metal Density Testing Method

Post by DirtScanner » Wed Dec 07, 2016 6:07 pm

Make sure they are to 2 decimal places Dave and the lower the range the more accurate they will be unless you spend lots on them ;)
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Re: Metal Density Testing Method

Post by chesters4 » Mon Apr 03, 2017 8:54 am

Very interesting post.
In one field i found a marked earing 875 and presumably an asian gold ring .
The earing came well down in foil as would be expected but strangely the ring came in as zinc! (Both on its side and on its edge)
Using the method in the post the ring weighed 9.1 gm and displaced 0.5gm so although your scale doesnt go above 22c its just above it so i guess just over 22c?
Cannot think of anything else it can be in the same field was a tungstan ring which was mighty heavy but not gold coloured

It does though mean a better set of scales is needed before i am absolutely certain
Does the method work if the ring has stones in it?

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Re: Metal Density Testing Method

Post by Koala » Wed Aug 09, 2017 3:36 pm

I have tried this a few times. Results are very hit and miss.

Solid gold ring bands work fine as long as you use scales with two decimal places. Three would be better.

However most of what we find is an unknown alloy. Also bubbles in the casting process alter the results greatly. I checked the results with an Irregular iron hinge thing. Results came back as aluminium due the internal bubbles.

Smooth objects should be fine. Might retest on some known coins and try and calibrate the setup as Water volume alters greatly with temperature and also affects the results.

Smaller the volume the better

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Re: Metal Density Testing Method

Post by Fusion » Wed Aug 09, 2017 4:55 pm

As stated in my earlier post:

In theory, you could obtain more accuracy by allowing for density changes of the water. Tap water has a slightly different density to that of pure water, and the density of water varies with temperature. However, if you look at how much difference these two factors make, it is really small, not worth bothering with whatsoever.

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Re: Metal Density Testing Method

Post by Trotboy » Sun Dec 03, 2017 11:17 pm

I don't see how this can be correct. Density is calculated by Mass (The weight of the object on your scales) divided by Volume (Which would be the millilitres of water displaced by the object. How can the scale measure volume? It can't, it can only give you a measurement of the mass.
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Re: Metal Density Testing Method

Post by Twit » Sun Dec 03, 2017 11:30 pm

Trotboy wrote:
Sun Dec 03, 2017 11:17 pm
I don't see how this can be correct. Density is calculated by Mass (The weight of the object on your scales) divided by Volume (Which would be the millilitres of water displaced by the object. How can the scale measure volume? It can't, it can only give you a measurement of the mass.
The object increases the volume of water weighed - it is as if the object was a volume of extra water, which via the weight of it measured, returns a density figure in the calculation.

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Re: Metal Density Testing Method

Post by Koala » Mon Dec 04, 2017 3:04 am

I have tried it.

Works fine for smooth things like a gold ring.

Irregular objects catch too many air bubbles.

Anything porous forget it.

Most alloys forget it as you don't know what percentage of each element.

Small items, small errors equal big differences. A small lead object that was both porous and irregular came back as aluminium.

Nice to add another diagnostic tool but recognise it limitations.

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Re: Metal Density Testing Method

Post by Dave8472 » Sun Mar 18, 2018 4:35 pm

Thread pictures fixed on first post

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Re: Metal Density Testing Method

Post by fred » Sun Mar 18, 2018 4:53 pm

MetalGuru wrote:
Fri Apr 26, 2013 10:50 pm
The boss wrote:Neil and Julie,if I'm wrong but you can tell me lol but I think it started when an old scientist sat in a bath n wondered why the water rises,he then filled a measuring cylinder n added different object to the same amount of water and then come up with a mass equasion which would of evolved into this density equation lol I think that's right any how lol
Absolutly correct. The scientist was Archimedes, who jumped out of his bath shouting eureka, which means, 'I've found it'.
All this makes my brain hurt. I'll probably just settle for having the bath. :D
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Re: Metal Density Testing Method

Post by Phil2401 » Sun Mar 18, 2018 5:10 pm

fred wrote:
Sun Mar 18, 2018 4:53 pm
MetalGuru wrote:
Fri Apr 26, 2013 10:50 pm
The boss wrote:Neil and Julie,if I'm wrong but you can tell me lol but I think it started when an old scientist sat in a bath n wondered why the water rises,he then filled a measuring cylinder n added different object to the same amount of water and then come up with a mass equasion which would of evolved into this density equation lol I think that's right any how lol
Absolutly correct. The scientist was Archimedes, who jumped out of his bath shouting eureka, which means, 'I've found it'.
All this makes my brain hurt. I'll probably just settle for having the bath. :D
Just out of interest (Fred you may know the answer to this) - how much does it cost to have your friendly local jeweller do an acid scratch test and give you an accurate assessment?

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Re: Metal Density Testing Method

Post by fred » Sun Mar 18, 2018 5:17 pm

Phil2401 wrote:
Sun Mar 18, 2018 5:10 pm
fred wrote:
Sun Mar 18, 2018 4:53 pm
MetalGuru wrote:
Fri Apr 26, 2013 10:50 pm

Absolutly correct. The scientist was Archimedes, who jumped out of his bath shouting eureka, which means, 'I've found it'.
All this makes my brain hurt. I'll probably just settle for having the bath. :D quote]

Just out of interest (Fred you may know the answer to this) - how much does it cost to have your friendly local jeweller do an acid scratch test and give you an accurate assessment?

Phil
Nothing if he thinks that you are thinking of selling it to him! :D Be wary though because many high street jewellers are little more than salesmen and have no knowledge of precious metals beyond reading hallmarks. ::g
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Re: Metal Density Testing Method

Post by Phil2401 » Sun Mar 18, 2018 5:31 pm

Thought that might be the reply :)

Below is a hardly scientific, but plausible account of the use of the Acrhimedes principle as a basis for measuring density -

http://www.longlongtimeago.com/once-upo ... den-crown/

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Re: Metal Density Testing Method

Post by Rhumours » Sun Mar 18, 2018 6:02 pm

:x| wait .... na na na na na ..... this is a lie ..... or witchcraft. .... or both ...... but it can't possibly work. You have displaced nothing. And it wasn't to measure density it was to measure the volume of a uneven object like .... a branch of a tree or a spiky ball something odd shaped. Bring the water to the top of the container ... whatever spilled over was displaced which meant that the lost volume of water was exactly the dimensions of the inserted object. No jokes :x| This can't work surely =)) .... you may have increased the density of the water very marginally which may be what is being registered :-/

And asking a jeweller to in essence value something usually carries a charge. If you want a piece of paper saying what it is that's a valuation for insurance purposes and usually costs 10% of the value of the item valued. "I would like this sized but not sure what metal it is could you check it is gold for me before I commit" is disgusting behaviour and I wouldn't offer that as a solution.
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Re: Metal Density Testing Method

Post by Phil2401 » Sun Mar 18, 2018 6:12 pm

Rhumours wrote:
Sun Mar 18, 2018 6:02 pm
:x| wait .... na na na na na ..... this is a lie ..... or witchcraft. .... or both ...... but it can't possibly work. You have displaced nothing. And it wasn't to measure density it was to measure the volume of a uneven object like .... a branch of a tree or a spiky ball something odd shaped. Bring the water to the top of the container ... whatever spilled over was displaced which meant that the lost volume of water was exactly the dimensions of the inserted object. No jokes :x| This can't work surely =)) .... you may have increased the density of the water very marginally which may be what is being registered :-/

And asking a jeweller to in essence value something usually carries a charge. If you want a piece of paper saying what it is that's a valuation for insurance purposes and usually costs 10% of the value of the item valued. "I would like this sized but not sure what metal it is could you check it is gold for me before I commit" is disgusting behaviour and I wouldn't offer that as a solution.
Rhumours - if you actually read the post, nobody is asking a jeweller to 'value' the item, but merely to establish its precious metal content.

If also you were to read thought my previous post, you would understand better the correlation between weight / displacement / density etc....the ancient theories are not dissimilar to contemporary opinions.

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Re: Metal Density Testing Method

Post by Rhumours » Sun Mar 18, 2018 6:20 pm

Phil2401 wrote:
Sun Mar 18, 2018 6:12 pm
Rhumours wrote:
Sun Mar 18, 2018 6:02 pm
:x| wait .... na na na na na ..... this is a lie ..... or witchcraft. .... or both ...... but it can't possibly work. You have displaced nothing. And it wasn't to measure density it was to measure the volume of a uneven object like .... a branch of a tree or a spiky ball something odd shaped. Bring the water to the top of the container ... whatever spilled over was displaced which meant that the lost volume of water was exactly the dimensions of the inserted object. No jokes :x| This can't work surely =)) .... you may have increased the density of the water very marginally which may be what is being registered :-/

And asking a jeweller to in essence value something usually carries a charge. If you want a piece of paper saying what it is that's a valuation for insurance purposes and usually costs 10% of the value of the item valued. "I would like this sized but not sure what metal it is could you check it is gold for me before I commit" is disgusting behaviour and I wouldn't offer that as a solution.
Rhumours - if you actually read the post, nobody is asking a jeweller to 'value' the item, but merely to establish its precious metal content.

If also you were to read thought my previous post, you would understand better the correlation between weight / displacement / density etc....the ancient theories are not dissimilar to contemporary opinions.

Phil

Phil :)

If you actually read my post as intended this would make sense to you ::g

https://www.google.co.uk/search?q=irony ... e&ie=UTF-8

I understand the principle just fine dude .... I did physics at school :D ::g
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