OK, dumb question? Perhaps

G

gazzahere

Member
Silver Stacker
Morning,

rightoh, put your coffee down - we don't want you spilling it laughing, here we go.



Will xrf see through a plastic sealed capsule to the surface of the metal?


Stop laughing you bastards :), just tell me.

have a great morning

Gazza
 
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
Sorry. :o
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:

Actually I have no idea. ;)
 
The depth an xray can "see" depends on the strength of the source being used (the source is whatever radioactive material they are using) and the type of material being xrayed. Soft tissue like plants, skin, muscle, plastic etc show up faintly on xrays whereas dense materials, metals, bones, minerals etc show up dark. A good place to research this would be any of the books put out on the subject of non destructive testing for welding. Hope that helped.
 
If I recall, the guy who XRF-ed my silver bar said it's possible to XRF a pamp gold bar in its original packaging.

That being said, I don't see why it wouldn't be possible to XRF a gold/silver coin through a plastic capsule. Though it could be better to take them out unless you have a good reason not to.
 
From the Olympus website...

For light plastics or light organic materials, penetration is on the order of mm or cm. For heavier plastics (like PVC), or plastics with metallic additives (like Ti, Zn), or aluminum alloys, penetration is on the order of a few mm. For heavier metal alloys (Ti, Fe, etc) penetration is on the order of 100s of um, and for the heaviest metals (gold, lead, etc) penetration is a few 10s of um.

Testing through a surface layer, whether it be corrosion, contamination, paint, or an anodized surface, depends on what is in the surface layer, how thick it is, and what elements are being tested in the substrate layer. It is always preferable to clean off a surface coating and test bare substrate. Surface coatings can partially or completely shield the substrate elements, and this is especially true for lighter elements like Mg and Al. If the surface coating is thin and the substrate elements are heavier (e.g. Pb, Sn, etc) then testing through the coating may be possible, though a user should validate that this is possible. Again, for best results it is always better to test a clean and uncoated homogeneous sample.

Cheers.
 
Not sure who Olympus is but I'm a Red Seal Certified Journeyman Welder and in my trade our welds are subjected to Xray NDT every day. Like I said it depends on the source being used, as they tailor the source strength to the type of material and depth of the shot. Time can also be substituted for strength, so the longer your "shot" the deeper you can test. I've had welds tested that were mere mm thick to things like slurry lines that are inches thick.

The absolute best reference for this type of information would be CSA, ASTM, ASNT books on the subject of NDT (Non Destructive Testing) or the equivalent in your country. Those three apply to North America.
 
my question basically came from something which can be a bit rough and ready.

I have 3 NZ 1980 dollars - the big silver coloured buggers.

I am sure about one - it is proof and silver I assume (92.5) - the other 2 I assume are unc cupronickel --------------- but I am not certain. They look it to me, but they have an odd oxidation on them like silver gets - they are in a box each - personally I find most of these boxes unpenetrable - hence my question.

If I have anything I know is special, I won't remove it from the box -- these kiwi things don't matter, but I wouldn't like to take something out like my Olympic 1kg or a Kook - the bloody thing is bound to hit the floor as I trip over the Scotty or something. :)

have a great day all and thanks for the comments.

gazza
 
If they're the ones I think they might be (1980 fantail) and packaged the same way, then the sterling proof will weigh 1.2 grams less than the cupronickel of the same coin....
:)
 
thanks for that.

how would I know the weight of the plastic boxes?

square for the 2 odd jobs and a round ? probably airtight for the silver one.

I can guess, but I could easily be a gram or so out.

tia :)

gazza
 
Ahh... that's a bit of a giveaway in itself. The cupronickels were issued in a square plastic box, green, with silver lettering. The proofs were issued in a round clear capsule inside a green display case.
 
yep, that's what I have - and I assumed that. I just wasn't 100% sure though and the oxidation on the squarebox jobs made me think - I am unsure why that is there - I think it must be reacting with the plastic or similar - after all, it doesn't happen in air - at least I don't think it does.

thanks again

Gazza:)
 
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