How do you get a coin to tone like this?

sportsfan007

I saw this listed a while back and cant figure out how they get these colors to pop like this? Blow torch, ovens, sulfur? I messed around with a few pieces of change and never got anything but black and brown crap.

MrSpud

Like this. This is the same coin with a picture taken every 8-10 seconds as the coin was being AT'd (thermal oxidation method). A film forms on the coin, as it gets thicker, the different colors appear. The progression goes from pale yellow to gold to orange to reddish purple then purplish blue to blue.

This kind of stuff should only be done for educational purposes though. If you do this to try and sell the coins, you'll just end up looking stupid and more and more people will avoid your auctions.

TwoSides2aCoin

the color of chemistry ?

TwoSides2aCoin

<< <i>the color of chemistry ? >>


or molecular change with temperature ?
or both ?

holeinone1972

thermal oxidation method).


What?????????

TwoSides2aCoin

I give up... you tell me !

TwoSides2aCoin

Voodoo ?

sportsfan007

I read a little about thermal oxidation in the semiconductor manufacturing process but that requires super high temps that most household ovens would never reach. Not sure how that is done with coins. Very cool nickels, btw. That eagle I posted has tiger stripes I wonder how come that didn't come out uniform like the nickels?

bidask

ice cream pigment from the 4th of July?

DieClash

Smoldering cigar in a paper bag! Pretty blue shades of toning!. AT for sure but I like the colors. Maybe not on a coin, but ......

morgansforever

All you need to tone a coin is a heat gun, and some tongs. Just don't get it to hot.

coinman420

<< <i>I saw this listed a while back and cant figure out how they get these colors to pop like this? Blow torch, ovens, sulfur? I messed around with a few pieces of change and never got anything but black and brown crap.


>>

Animalkeeper

Mr. Spud - Thanks for the post. I knew this was being done. Thanks for being instructive on what ends could be achieved.

MrSpud

here's more on thermal oxidation for those that really want to know
link

coinman420

i think there are so many ways a coin can tone that it is almost infinite, some natural and some not so natural. i`ve stated here before that i work in an electroplating shop so i have access to some chemicals most people don`t. i experiment to see different results to help me identify AT vs. NT coins. these two coins were given s silver "flash" and then rinsed and dried. a couple days exposed to air and this happens. again i would never try to sell anything i do this with, i do it only to see the chemical reactions.

TwoSides2aCoin

And when you get a bodybag, PCGS will attach this note :

By anodic oxidation and thermal oxidation, thin oxide films were formed and those contribute to coloration due to optical interferences in film. Coloration using anodic oxidation was affected by applied current, electrolyte type, and surface condition of substrate metal. For consistent coloration, this variability in color could be overcome by combining real-time color measurement system. Inherent coloration of the oxide film itself could be obtained by using hydrothermal spray oxidation technique combined with doping of 3d transition elements, which form new impurity energy levels in the energy band gap of TiO2.

Followed by this recommendation:

Do not try this at home !