I have to make some curb chain from 1.5mm palladium wire. To check
the mandrel size I first wound a couple of links around a piece of
round rod and was dismayed to find that an orange peel effect
occurred on the wire ans shown in the following photo:
I sent the wire back and a couple of weeks later got a new length,
but it displayed the same orange peel effect as before, so I
complained loudly and yesterday got another replacement. It is
better, as shown in the following photo, but I still don’t think its
acceptable. http://tinyurl.com/87rufh
I don’t recall this ever happening with gold or silver, but just to
make sure I wound a couple of links from Sterling silver. This photo
shows no such surface defect. http://tinyurl.com/6uabmp
Is this an inherent property of palladium (in which case I can’t use
it for making chain), or is this another faulty batch from the
bullion dealer?
I think that’s a property of the metal, particularly after annealing.
I haven’t let that affect my willingness to work with it, however. I
just needed to spend some more time finishing it.
How are you annealing the wire? If you over anneal palladium (and to
a lesser extent platinum) you can get excessive grain growth which
(if my reading is right) can give a grainy surface on bends.
I do quite a bit of palladium work now and when I anneal I hold at a
bright orange for a count of “twenty elephants”, works for me and
saves having to take my eyes of the work to check a watch, allow to
cool to black (no colour given off, but as the metal is shiny it
won’t go black) then quench in water.
One thing when I make curb chain is I pre-finish half the links
(solder and clean them up so there isn’t any excess solder etc.) and
before I roll the chain I do so again for the newly solder links to
do this I use rubberised abrasive wheels in my flex shaft I think
that this would clear up the orange peel quite well and as palladium
is really ductile there shouldn’t be any internal problems that
would keep you from making a high quality chain anyway.
How are you annealing the wire? If you over anneal palladium (and
to a lesser extent platinum) you can get excessive grain growth
which (if my reading is right) can give a grainy surface on bends.
I didn’t anneal it myself, it came fully annealed from Cookson’s, the
bullion dealer I use here in UK. The chain will have 172 links formed
by winding onto a 4mm mandrel. I don’t relish the prospect of
smoothing orange peel from 172 little links.
That’s interesting and unfortunate. I’m about to try a project with
palladium for the first time, so I really would like to know what’s
happening with your wire. Was it fully annealed when you bent it?
Even though my supplier states that the stock is annealed I always
assume that is really isn’t and as it only take a moment to anneal it
I see it as time well spent.
Get some fine grit rubber wheels (800grit or better, but don’t go
over 1200 as it will take too long) and when you have finished the
soldering just run over the chain bit by bit to bring it up to a
uniform finish. This will get rid of the surface oxide formed during
soldering AND get rid of the orange peel in one operation. Then
proceed as you would normally.
I will try to post a picture of a freshly bent piece of annealed Pd
to see if what you’re describing is what I consider the normal “as
bent” surface.
I didn't anneal it myself, it came fully annealed from Cookson's,
the bullion dealer I use here in UK. The chain will have 172 links
formed by winding onto a 4mm mandrel. I don't relish the prospect
of smoothing orange peel from 172 little links.
I don’t know if this would work, I’ve never tried it.
What about drawing the wire through 1 or 2 holes in a draw plate
before winding into coils? That will reduce the diameter a little,
but hopefully not too much & it might get rid of the pits.
I wouldn’t want to have to polish 172, 4 mm links either.
I have not noticed this with the Pd 950 alloys I have been using are
you using Pd 950 or pure Pd? I did notice the orange peel with pure
Pd after annealing with little cold work in it.
I don't relish the prospect of smoothing orange peel from 172
little links.
Justa shot here but I think you should be able to buff the assembled
chain to an acceptable finish. Granted, free lengths of chain have
their considerations when polishing but keep the chain short and the
wheel slow, you should be OK. Use a white bristle brush to get
inside. Might not loupe out as perfect but it should face up pretty
well. If you don’t have a two speed buffer, wrap the chain around
something to hold it safely(personally, I don’t like this method,
I’d rather feed the chain by hand into the wheel 2 inches at a time,
held taught, that’s why I have a 2speed and dirty fingertips)
