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Issues applying patina to copper electroformed piece


#1

Hi-

I just joined so i’m not positive how this works. Basically I have
recently started electroforming with copper. For the most part
everything is going fine (still some kinks) but the one problem i
keep running in to is the patina. If i apply Liver of Sulfer or
Silverblack to the piece after cleaning it and sanding it, it turns
black but when i even touch it the color either slides off or it
will literally flake off, showing shiny copper underneath. I have
been able to get it to stay to an extent by applying the LOS after
burnished the entire item, sanding it with the flexshaft and then
brushing it. However, even after doing this the color will come off
in spots. I’ve tried researching it online but its proved difficult.
I’m at a loss as to the reason behind this is happening and how to
prevent it and would love any advice whatsoever.

Thanks!
Sam


#2

Sam,

I’ll bet that part of your problem is you may be putting the patina
on too thick. Also, electroforms can often be quite dense, and if
polished, may have less porosity than, say, castings, which means
essentially that the patina is on a smoother surface, so more easily
worn off.

I’d suggest trying with more dilute LOS. warm or hot, but dilute
enough so the color changes only slowly when you put the metal in.
Let it get almost to the color you want, then remove, and using a
very fine brass bristle brush (these are called “platers brushes”,
and are fine enough bristles so they feel actually soft to the touch,
rather than like a wire brish), scrub the surface with that brush,
using more LOS liquid on the brush. The brass brush burnishes the
patina color layer, compacting it, and making it much more durable,
and the use of LOS on the brush lets the color reach it’s final shade
while you do this. The color you get this way is often more of a
blue/black or gunmetal color rather than dead matte black, but it’s
attractive. Applying the patina this way, slowly with
brushing/burnishing, you get a more even coat, and thin enough so
it’s less likely to flake off. Also, any resistant areas show up
while you’re applying the color, you just keep on working it,
brushing and dipping, until it’s uniform.

Hope that helps
Peter


#3

HI, I don’t know much about anything, and I don’t do electroform, but
I work with copper some. Try spraying the piece lightly with the
clear spray for cars. OUTDOORS!!

I use Perfect Match sometimes. From O’Reilleys. I have started to set
the piece on a metal outdoor chair that has a metal mesh seat, and
spray both sides. wait a while spray again.

Roxy Lentz


#4

Sam, I heartily second everything that Peter Rowe said. In fact, I
learned about plater’s brushes from Peter here on Orchid a long time
ago. My patina life was changed forever! They are large very soft
bristle brass brushes, a little more expensive than a regular brass
brush. The brush evens out the surface and makes the patina integral
with the metal. It will leave a satin surface but you won’t have
scratches. Some suppliers don’t actually call them “plater’s
brushes” so they can be difficult to find. Not everyone carries them

  • Otto Frei is a good source. I believe they have two sizes.

The only thing I’d add to Peter’s post is that you don’t need to
sand your pieces to clean them. After you neutralize the acid, just a
normal pumice clean should be sufficient. Then build up your color
slowly with several applications and brushings. If you warm your
piece up first with warm water it will speed the process and make the
color a little more even.

Rene Roberts