heat coloring copper physics

I have been heat treating a mirror polished copper pendant to color it
with a mapp gas torch and have 2 questions.
1. When I stop heating the pendant it continues to change color as it
cools for the next few minutes - what is happening? (I heat treat
Titanium to color but I imagine that there must be a differant process
going on with copper)
2. If I quench the copper in water it immediately develops a bright red
opaque 'skin'. What is this, and, again, can anyone explain to me what
is happening?

I know there is a book, 'the coloring, bronzing and patination of
metals that would probably explain this, I will buy it some day, but
until I can put aside the money I hope someone can give me some clues
to understanding what is going on.

Thanks,

Ben

wrote:
I have been heat treating a mirror polished copper pendant to color it
with a mapp gas torch and have 2 questions.
1. When I stop heating the pendant it continues to change color as it
cools for the next few minutes - what is happening? (I heat treat
Titanium to color but I imagine that there must be a differant process
going on with copper)
2. If I quench the copper in water it immediately develops a bright red
opaque 'skin'. What is this, and, again, can anyone explain to me what
is happening?

I know there is a book, 'the coloring, bronzing and patination of
metals that would probably explain this, I will buy it some day, but
until I can put aside the money I hope someone can give me some clues
to understanding what is going on.

Thanks,

Ben

If you experiment a little with your torch, and heat some copper with an
oxidsing flame then with a reducing flame,( assuming you know how to
adjust your torch to do this) you will see that its not the flame that
colours the copper but the oxigen or lack of it in the flame that does.
so from these basic principles your copper is continuing to oxidise from
the air till it cools sufficiently to the point that oxidation from the
air stops.If your after a particular colour you need to stop heating
long before the flame gives you the colour. Run some experiments youll
see what I mean.
As for Titanium colouring , as its far les reactive at the colouring
temperature range your using it stops oxidising as soon as you remove
the heat and it starts to cool.#
As for quenching your copper, most water contains dissolved oxygen,
chlorine and other minerals depending wether its hard or soft on the ph
scale.
Because your putting hot metal into this mix you are getting a much
higher reaction rate over time than if you put the same copper into the
same water cold.What ever is in the water is changing the copper
surface/ oxide. to the colour your getting despite the fact its probably
from your tap and is standard drinking water.
If your colouring copper the last thing you shoud be doing is quenching it.
there are simple ways to colour copper without using heat. the simplest
is to use flowers of sulphur or sulphide lumps. It smells of bad eggs.
Again expetriment with a little at a time in water with 1 drop of wash
up liquid to act as a wetting agent.