[modeleng] Re: Interesting Effect

Clif,

The copper comes from previously pickled objects. Copper oxide will dissolve 
in the acid to produce a copper salt (copper sulphate if you use sulphuric 
acid). This will react with any iron in a displacement reaction, because 
iron is more reactive than copper.

I'm sure the real chemists will tell us that it's all more complicated than 
that!

I'd attempt to write a couple of chemical equations but I don't think we can 
use subscripts here....
Ah lets try anyway

 Copper oxide dissolving in acid
CuO + H2SO4 = CuSO4 + H2O

And
replacing the iron in the steel

Fe + CuSO4 = FeSO4 + Cu

I know that ions are involved in reality but I think that adds to the 
confusion when explaining it!

Hope that is of some interest.

JohnP


----- Original Message ----- 
From: "Clifton Walker" <clif.gwr@xxxxxxxxxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Monday, January 22, 2007 8:42 PM
Subject: [modeleng] Interesting Effect


HI All,
Continuing the manufacture of my Buffers for a Wagon, I had an interesting 
effect.
I had silver soldered the shanks onto the heads and being lazy decided to 
remove the Flux residue by chucking them into some acid. Now the acid is old 
stuff previously used for cleaning copper and brass items.
They are Mild steel but when I got them out after only about half an hour 
they had a beautiful copper plated finish.
If I had wanted to copper plate them then, I would have expected to have to 
wire them up to a battery and put in a sacrificial anode but there they were 
all coppery, free for nothing.
 What happened?

The finish only being thin, did partially rub off using emery paper.

The wagon under construction as a matter of interest is a creation of mine 
to clean my Aluminium Track. The track being only small gets a build up 
after a couple of hours running of Oil and Water which turns into a grey 
paste which then gives endless wheel slip.
This wagon is designed to have electric motorised roller brushes fed with 
either White Spirt or Parafin from a small feed pump worked from one of the 
axles.Hopefully it will wash the muck off the rails.
 Time will tell if it is going to work as I seem to have trouble these days 
getting into my Workshop.

Regards

Clif
MODEL ENGINEERING DISCUSSION LIST.

To UNSUBSCRIBE from this list, send a blank email to,
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject 
line.



-- 
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.17.5/645 - Release Date: 22/01/2007 
16:10



MODEL ENGINEERING DISCUSSION LIST.

To UNSUBSCRIBE from this list, send a blank email to, 
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.

Other related posts: