From: dwilkins@northernnet.com (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Electroforming Supplies?
Date: Fri, 09 Feb 1996 17:23:28 GMT

On 8 Feb 1996 19:56:05 GMT, osan@hansel.mt.att.com (Demon Buddha)
wrote:

>Mike Rehmus  <mrehmus@grayfax.com> wrote:
>>Robert,
>>
>>What is electroforming?
>
>	It's kinda like electro plating on steroids.  It can
>	produce light to very heavy plating on any object
>	that will conduct electricity.  In the jeweler's
>	trade it is used for things like making extremely thin
>	earrings from, say, a canary's feather.  Feather gets
>	painted with a conducting solution and the plate goes 
>	over it, preserving the extremely fine details of the
>	object.  Afterward the object can be burned out of the
>	plating if desired.  It's a very cool art metal process
>	and I'm sure it also has its place in other manufacturing
>	circles as well.
>
>	Generally speaking you cannot electroform with electroplating
>	apparatus, though I don't know why.  This is what I've heard.

Actually it can be done but without proper attention to details it is
difficult to build up a thick coating without a great deal of stress
in the plate. The writer is probably correct because most people will
not know how to control the potential at the cathode.

One of the tricks to building thick deposits by electroforming is to
plate and then reverse the current to remove material. It is sort of
like taking two steps forward and one step back. This process if
properly setup will give a more dense product with less stress. There
was a process developed for making silver crucibles using this
technique where the silver was deposited in this manner on an iron
crucible. After the deposition was finished the iron crucible was
dissolved with muriatic acid leaving a dense silver crucible. 

  _               _   _                  Für d' Flöh gibts a Pulver 
 (_|   |   |_/o  | | | |  o              für d' Schuach gibts a Wix, 
   |   |   |     | | | |      _  _    ,   für'n Durst gibts a Wasser
   |   |   |  |  |/  |/_) |  / |/ |  / \_  bloss fuer d' Dummheit gibts nix.
    \_/ \_/   |_/|__/| \_/|_/  |  |_/ \/ 

From: Chuck Harris <cfharris@erols.com>
Subject: Re: Silver Plating HELP
Date: Aug 08 1996
Newsgroups: rec.crafts.metalworking

Jim Stickney wrote:

> What is the easist/cheapist way to do a small amount of silver plating, onto
> brass

Use any of a number of "electroless" silver plating solutions that are
available to the electronics industry.  They don't give you the thickness
that can be achieved with electroplating, but they are very simple to
use.

To actually do electroplating requires a fair
amount of knowledge, and a good bit of chemistry.  These are the basic
steps used in industry:

1) string the material to be plated on copper wire 
2) put in a hot lye solution to remove grease and finger oils.
3) rinse in clear water.
4) put in aquaregia acid bath (HNO3+HCl+H2SO4) to remove tin from
   surface of brass.
5) rinse in clear water (really well!!)
6) put in dilute electroless silver plating solution (acts as "seed" for
   the soon to be electroplated silver.
7) rinse in clear water
8) put in silver plateing solution (Na0H + NaCN + Ag(CN)2) The "CN" is,
   of course, cyanide. apply about 10A / sqft as I recall.  The amount of
   current is largely an art, as it depends on the shape of the object,
   how many sharp points it has, how deep the cavities are...  Too little
   current, and the plating comes out milky, too much, and it is crusty on
   the corners.  (the chemical balance of the plating solution is also
   very important to the final result.)  You should be able to plate
   a mirror finish on your object.
9) rinse in clear water.
10) put in potassium chromate solution to apply thin slightly protective layer.
    (without the chrome, we couldn't even get the chassis's out of the factory
     without finger prints!).
11) rinse very well in clear water.
12) dry with shop air gun.

I used to do all of the silver plating for NASA's primary telemetry receiver
contractor (DEI) when I was a 15 year old kid in the early '70s.

-----
Chuck Harris - WA3UQV
cfharris@erols.com

Subject: Re: Silver plating - how to do it?
From: gwhite@tiac.net (Doug White)
Date: Apr 24 1996
Newsgroups: rec.crafts.metalworking

In article <txCEpHAJqIfxEwCK@bosagate.demon.co.uk>,
   Marc Line <marc@bosagate.demon.co.uk> wrote:

>In article <4lbo9h$pkd@news.tiac.net>, Doug White <gwhite@tiac.net>
>writes
>
>>I have a small bottle (somewhere) of silver plating powder.  It's a 
>>mixture of silver nitrate, table salt, and cream of tartar (I'm not 
>>kidding).  The original recipe was in an old Ham radio magazine for 
>>silver plating RF components.  You wet a rag, and put some powder on it 
>>to make a paste.  Rub vigorously on brass or copper, and it plates out 
>>right onto the metal.  I think the cream of tartar is used as the flux to 
>>remove any residual oxides.  If no one else comes forward with the 
>>proportions soon, I'll see if I can find my bottle and I'll post back.
>>
>>Doug White
>
>Thanks for your post Doug.
>
>I tried something similar with a commercially available fluid but the
>coating was nowhere near uniform enough for my purposes.  I suspect that
>the silver content was a little on the low side.
>
>I should appreciate it if you could post details of the proportions of
>components in your powder/paste as I'm keen to try anything and
>everything to get the results I need.

OK, I remembered that I'd loaned my stuff to a friend, and I called him 
to get the proportions off the bottle:

  1 part-by-weight Silver Nitrate
  2 parts-by-weight table salt
  2 parts-by-weight Cream of Tartar

You just mix them together, and apply as instructed above.  After giving 
it some thought, it may only work on copper and copper alloys.  I've 
never tried to get a particularly heavy plating out of it, but I suspect 
that may be difficult or impossible.  One other problem is that the only 
silver nitrate I could ever find comes in fairly coarse crystals.  For 
best performance, you may want to pulverize and sift the ingredients 
before mixing them.

Enjoy!

Doug White

Subject: Re: Silver plating - how to do it?
From: dwilkins@northernnet.com (Don Wilkins)
Date: Apr 24 1996
Newsgroups: rec.crafts.metalworking

On Wed, 24 Apr 96 02:24:14 GMT, gwhite@tiac.net (Doug White) wrote:

Whole bunch of stuff snipped.

>OK, I remembered that I'd loaned my stuff to a friend, and I called him 
>to get the proportions off the bottle:
>
>  1 part-by-weight Silver Nitrate
>  2 parts-by-weight table salt
>  2 parts-by-weight Cream of Tartar
>
>You just mix them together, and apply as instructed above.  After giving 
>it some thought, it may only work on copper and copper alloys.  I've 
>never tried to get a particularly heavy plating out of it, but I suspect 
>that may be difficult or impossible.  One other problem is that the only 
>silver nitrate I could ever find comes in fairly coarse crystals.  For 
>best performance, you may want to pulverize and sift the ingredients 
>before mixing them.

This reaction is driven by the reduction of silver ions to the metal
by the copper. You will never build up a thick layer because as soon
as the copper is completely covered with silver there is nothing to
drive the reaction.

You get a similar type of reaction when you dip a knife (iron) blade
into a copper solution. It is called internal electrolysis and is
useful for applying an extremely thin layer.

  _               _   _                  Für d' Flöh gibts a Pulver 
 (_|   |   |_/o  | | | |  o              für d' Schuah gibts a Wix, 
   |   |   |     | | | |      _  _    ,   für'n Durst gibts a Wasser
   |   |   |  |  |/  |/_) |  / |/ |  / \_  bloss fuer d' Dummheit gibts nix.
    \_/ \_/   |_/|__/| \_/|_/  |  |_/ \/ 

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Rectifier for copper electroplating?
Date: Sat, 27 Mar 1999 15:14:00 GMT

On Fri, 26 Mar 1999 22:43:53 -0500, "Gary H. Lucas" <gary@ushwy1.com>
wrote:

>Variable Transformer, takes 120vac in puts out from 0 to about 130vac
>typically.  Get a full wave bridge rectifier from Radio Shack and maybe a
>large DC capacitor for a little filtering and you are all set.  I can get
>you a variac cheap, let me know.
>
The problem with this type of setup is that one needs only a few volts
for electroplating. The knob on a variac takes you from one turn to
the next on the transformer and the proper voltage may require
something like half turn increments (or even tenth turn increments).

If you are going to build this I would suggest a 110 to 6.3 volt
transformer between the variac and the rectifier. That is a common
(cheap) transformer and then the knob on the variac will give you an
adjustment range from 0 to 6+ volts.

I visualize a similar problem with the suggestion of using a twelve
volt battery. Voltage adjustment is not easy without a variable power
resister.

Voltage (current density) can be critical to obtain a good
electrodeposit.

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Plating Aluminum
Date: Mon, 04 Jan 1999 16:01:49 GMT

On 2 Jan 1999 05:14:49 GMT, "Don Foreman"
<foreman_don@htc.honeywell.com> wrote:

>The zincate is very thin -- it's only in there for a minute.  Caswell sez
>0.2 mil of nickel for general decorative indoor items, 0.5 to 0.8 mils for
>hand tools, handguns, etc, 0.7 to 1.5 mils for high corrosion resistance.
>You can monitor progress by hanging the work on aluminum wire and miking
>the plated wire, compare that to unplated.

By their nature these coatings need to be thin or porous. You have an
electrolytic cell where (in this case) zinc is being reduced to the
metal by aluminum. Once the aluminum surface is completely covered the
reaction comes to a screeching halt since there is no longer aluminum
metal exposed to the zinc in solution.

>But I'd think you'd want to mask the bronze fittings from plating, just as
>you might from anodizing.

Without looking it up my guess is that zinc won't deposit on the
bronze. I suspect that a subsequent nickel coat will deposit on the
bronze.

>I wouldn't think oil and vibration would be a problem, but high temps might
>"lift" the plate due to differential expansion. Caswell says to be careful
>not to get things too hot while buffing.  I got some minor blisters in the
>copper at soldering heat.  Bead-blasted aluminum  had the best adhesion.

Heat can lift electro deposits. Frequently there is occluded water in
the deposit as well as gases. Get it too hot and the plate gets blown
off. Differential thermal expansion also causes failures in addition
to mis-matches in lattice parameters. Originally iron was plated with
copper, followed by nickel and then chrome. Cost savings eliminated
the flash copper and that is one of the reasons why more recent chrome
plates are not as good as the older practice.

Bead blasted aluminum probably has more surface area.

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Brass Plating
Date: Fri, 23 Jun 2000 16:45:08 GMT

On Thu, 22 Jun 2000 23:05:28 -0500, "gcouger"
<gcouger@mercury.rfdata.net> wrote:

>,;
>,;"PLAlbrecht" <plalbrecht@aol.com> wrote in message
>,;news:20000622210549.22999.00002279@ng-fh1.aol.com...
>,;: >Can someone direct me to sources of information regarding brass plating
>,;: >steel and aluminum.  Books, articles etc. also mail oder platers known
>,;to do
>,;: >good work. Thanks
>,;:
>,;: Don't know if aluminum can be plated.
>,;:
>,;Alumunium can be plated. I am not sure you can plate anything with brass.
>,;It is a alloy of copper and zinc and the tow have very different plating
>,;qualities. I am sure that they have something that looks a lot like brass
>,;because I have seen it.

Aluminum is tough to plate with anything but it can be done. There are
two problems.....

(1) That rather tenacious oxide coating is not a desirable surface for
plating. The damned plate doesn't stick.

(2) If you get the oxide coating off the aluminum then you have a
rather reactive metal surface which wants to react with something in
the plating bath. Whatever it reacts with usually follows Murphy's Law
and interferes with the desired plating reaction.

As for plating brass... Yes it can be done but it is not for the
novice. The ratio of Cu to Zn in the plating bath determines the
composition of the brass plate. However due to the different half-cell
potentials for  Cu and Zn the ratio in the bath is different than the
ratio in the plate.

The result is that as you plate brass the composition of the bath will
change unless you do something to prevent it. If the composition of
the bath changes then the composition of the brass you plate will also
change.

There are ways keep this problem under control but as I said earlier
it is not for the novice.

The Metal Finishing Handbook or the Electroplaters Handbook should
give you some info to start. There was a lot of work done on this at
the US Bureau of Standards years ago. If you have access to a good
technical library you should be able to find some of that research.

I got over 14000 hits on a web search. Read 20 and got two clues.
Caswell sells a brass plating solution ($59 per liter) It does not
contain cyanide so is probably fluoborate. The other clue was that
there were some questions about brass plating from the stained glass
hobbyists. Those people might have some useful information.

From: REMOVE_THISdwilkins@means.net (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Iron electroplate
Date: Fri, 25 Feb 2000 13:38:19 GMT

On Thu, 24 Feb 2000 21:41:51 GMT, "Randy O'Brian"
<rasek@worldnet.att.net> wrote:

>,;Can anybody tell me which of the commonly available electroplating tech
>,;books contains a recipe or process info for electroplating iron onto a low
>,;carbon steel surface?   I have a welded assembly that will not hot black
>,;oxide evenly and figure a little iron plate will allow an even finish.

You should be able to find the information "metal Finishing" or the
electroplating handbook.

We did this long ago to put a coating of radioactive iron metal on a
iron wire. Long enough ago so that I no longer will swear to all of
the details.

Faint memory tells me.

We plated from an acidic chloride solution.

We used a divided cell. If you don't do this you soon are reducing
iron(III) to iron(II) at the cathode and running the reverse reaction
over at the anode. In other words nothing gets plated.

I don't recall any difficulties. We had one vial of radioactive iron
and the stuff plated on the first try.

A word of caution. Try it on something first that you can throw away
if it doesn't turn out OK. Heat treating frequently pops electroplated
layers.