Log in or Sign up
Coin Talk
Home
Forums
>
Coin Forums
>
US Coins Forum
>
What do you see in these images that indicate improper cleaning?
>
Reply to Thread
Message:
<p>[QUOTE="Lehigh96, post: 7927697, member: 15309"] <ol> <li>This appears to be whizzing, but it makes no sense to just disturb the metal around the devices and lettering and leave the fields undistrurbed.</li> <li>This is a common effect known as "pull away" toning where areas under the peripheral lettering/stars is resistant to toning and remains untoned while the rest of the coin exhibits toning. As a former metallurgist, I've contemplated that the cause of this might be localized strain hardening caused by the strike pressure, but I have no plausible explanation why that would inhibit toning, other than to reduce the diffusivity rate in the area.</li> <li>That isn't a very good photo, and to me it looks simply like someone spilled a liquid in the coin that either couldn't be removed or no attempt was made to remove it.</li> </ol><p>[/QUOTE]</p><p><br /></p>
[QUOTE="Lehigh96, post: 7927697, member: 15309"][LIST=1] [*]This appears to be whizzing, but it makes no sense to just disturb the metal around the devices and lettering and leave the fields undistrurbed. [*]This is a common effect known as "pull away" toning where areas under the peripheral lettering/stars is resistant to toning and remains untoned while the rest of the coin exhibits toning. As a former metallurgist, I've contemplated that the cause of this might be localized strain hardening caused by the strike pressure, but I have no plausible explanation why that would inhibit toning, other than to reduce the diffusivity rate in the area. [*]That isn't a very good photo, and to me it looks simply like someone spilled a liquid in the coin that either couldn't be removed or no attempt was made to remove it. [/LIST][/QUOTE]
Your name or email address:
Do you already have an account?
No, create an account now.
Yes, my password is:
Forgot your password?
Stay logged in
Coin Talk
Home
Forums
>
Coin Forums
>
US Coins Forum
>
What do you see in these images that indicate improper cleaning?
>
Home
Home
Quick Links
Search Forums
Recent Activity
Recent Posts
Forums
Forums
Quick Links
Search Forums
Recent Posts
Competitions
Competitions
Quick Links
Competition Index
Rules, Terms & Conditions
Gallery
Gallery
Quick Links
Search Media
New Media
Showcase
Showcase
Quick Links
Search Items
Most Active Members
New Items
Directory
Directory
Quick Links
Directory Home
New Listings
Members
Members
Quick Links
Notable Members
Current Visitors
Recent Activity
New Profile Posts
Sponsors
Menu
Search
Search titles only
Posted by Member:
Separate names with a comma.
Newer Than:
Search this thread only
Search this forum only
Display results as threads
Useful Searches
Recent Posts
More...