Subject: Re: help: household dies?

From: Jeff Mayhew <[email-masked]>
Date: 14 May 1996 15:08:53 GMT

[email-masked] wrote:
>In Briney's "Home Machinist;s handbook" he mentions a way to imitate aluminium anodozing.
>He say's  one must use a lye solution and then "a solution of household dye".
>
>Can anyone tell me what dies are these?
>Where I can purchase small quantities?

I suspect he is referring to "Rit" dyes, mainly used for dying clothes
and other household articles.  This is typically available at almost
any grocery store or department store (in the U.S., that is).  Back in
the 60s and 70s the fad of "tie-dying" T-shirts made these dyes pretty
popular.

Jeff Mayhew
[email-masked]

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From: [email-masked] (Don Stauffer)
Date: 15 May 1996 08:38:03 CDT

In article <[email-masked]>, [email-masked] says:
>Hi!
>I'm looking for a dull black and a britght white.
>
>Many Thanks!
>
>eduardo haddad filho
>[email-masked]
>

The dyes most recommended for this are fabric dyes.  Some people have 
used food coloring dyes with so-so success.  The use particularly of 
aniline type fabric dyes is an old trick in ham radio.  The lye-converted 
surface goes way back in amateur electronics.

Don Stauffer in Minneapolis
[email-masked]

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From: [email-masked] (Edk4)
Date: 15 May 1996 17:09:21 -0400

>The dyes most recommended for this are fabric dyes. Some people 

>[email-masked]

This idea is extremely interesting. Can someone post the
specific lye solution 'formula'  and the process involved to
use fabric dyes to color Aluminum.

How 'fast' are the colors. I have an Aluminum blackening
agent which, unless I prepared the surface poorly, only put
on a thin powdery coating which rubbed of without much
difficulty. I believe it was 'Birchwood Casey Aluminum Black'.

I could definitely use an in-shop alternative to anodizing, even
if it's only half as good.

------------------
Ed Kingsley

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From: [email-masked] (Robert Grauman)
Date: Wed, 15 May 1996 22:52:05 mountain

In article <[email-masked]> [email-masked] writes:
>From: [email-masked]
>Subject: help: household dies?
>Date: 14 May 1996 13:54:42 GMT

>[email-masked]

I'm not familiar with the lye method of anodizing aluminum, but I use an
oxalic acid method for anodizing aluminum, using 15 to 25 volts, AC (not DC).
I use household dyes to colour the aluminum after the anodizing process.
The dye I use is the type used to dye cloth.  It is available here in the
local supermarkets and some drug stores.  One of the brand names is
RIT.  The instructions for most of the dyes used for cloth state that vinegar 
must be used as a "mordant".  I understand that the aluminum hydroxide acts 
as its own mordant or dye fixative, so I don't use vinegar.  I just boil the 
aluminum object fresh out of the anodizing bath in a strong solution of the 
dye in distilled water.  The colours are not brilliant, but rather subtle and 
kind of transparent.  I doubt if you will be able to get a bright white 
anodize, but don't be afraid to experiment on scraps of the same material as 
you will be using.  I am pleased with my yellows and reds.

				RJG

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From: [email-masked]
Date: 14 May 1996 13:54:42 GMT

Hi!

Many Thanks!

eduardo haddad filho
[email-masked]

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From: [email-masked] (Edk4)
Date: 17 May 1996 07:52:10 -0400

>I use household dyes to colour the aluminum after the anodizing process.

Bob

Could you explain the oxalic acid process, please.

------------------
Ed Kingsley

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From: [email-masked] (Robert Grauman)
Date: Sat, 18 May 1996 22:56:58 mountain

In article <[email-masked]> [email-masked] (Edk4) writes:
>From: [email-masked] (Edk4)
>Subject: Anodizing Aluminum with household dies?
>Date: 17 May 1996 07:52:10 -0400

I don't know if the oxalic method has any advantages over other methods
of anodizing aluminum.  It's just the method I learned and now use.
I use 10 ounces of Oxalic acid per (Imperial) gallon of distilled water.
To disolve the oxalic acid in the water, I boil about half of the water
and stir in the oxalic acid.  After it cools down, the rest of the water is 
added.  During anodizing, I try to keep the temperature at about 35
degrees C.  The objects to be anodized are cleaned in a strong
detergent solution and divided into two piles with more or less the
same surface area.  I suspend the parts from the bars in my plating
tank, using aluminum wire, (purchased from Radio Shack).  I  have
an old transformer I liberated from who knows where which puts out
25 Volts, AC at about 10 amps.  I use a Variac variable transformer
to control the voltage into my 25 volt transformer.  I apply 8 to 10
amps per square foot of material hanging on one of the bars.
I start at 15 to 16 volts, but the current will drop off, and the voltage
must be increased, eventually reaching 25 volts or more.  The
process is slow, and I have found that about ninety minutes is
required to get a good surface.  Go do something else in the shop
and check the bath every 20 minutes or so.

Some alloys will give a smutty appearance to the anodize.  I understand
that it is the presence of copper in the alloy that causes this.

Following the anodising process, the objects are immediately rinsed
in clear water and then boiled in the dye solution.  I use ordinary dye
for cloth (RIT) purchased at the supermarket.  The instructions that
come with the dye usually say that vinegar (acetic acid) is required
as a mordant.  The vinegar is not required for this process.  I usually
mix the dye a little stronger than specified.  Some colours are more
successful than others, and some experimentation is required.  I am
pleased with my reds and yellows.  I haven't been successful in getting
a nice deep black colour yet.

Hope this answers your question, Ed.

				RJG