[ARC5] Screws for ARC-5s

[Mike Hanz]

WA5CAB at cs.com wrote:

>But the finish process is known as black oxide.  Today it is considered 
>dangerous and most places have quit doing it.  It was used as both a protective and 
>a decorative finish on copper, brass, bronze, iron, steel and some stainless 
>steel parts.  Gate, fence and fireplace hardware was often black oxide 
>finished.  Unfortunately, it is difficult to find anyone who still does steel or 
>stainless steel, at least in the US.  The place here that used to do it for me had 
>a man killed two years ago and they quit doing it on anything except copper 
>or copper flash parts.  Apparently, the pot temperature for copper is much 
>lower than for the ferrous metals and not nearly as dangerous.
>

There seems to be varying degrees of these processes.  The stainless 
alloy used in many screws, 18-8, is resistant to the more benign 
solutions, but my favorite source for these things (Brownells) has a hot 
tank chemical that will do it.  The downside is the minimum order - it 
takes processing in Oxynate No. 84 (at $100) followed by Oxynate No. 7 
(at $80) but the good news is that these prices include 40 pounds of 
each - prolly a zillion 3-48 screws.  :-)    I like Ken's approach and 
have used it successfully on #6 and up screw sizes, but if you just 
/have/ to have a black finish on stainless that is indelible, best bet 
is to contact Brownell's and see who some of their biggest customers for 
this stuff happens to be.  By the way, if you enter the term "bluing 
chemicals" into their search engine, you'll get a wide variety of hits.  
For $20-30 you can get a lifetime supply of solutions that will cover 
everything from brass to aluminum and some in between, like solder.  My 
staple here in the shop for steel parts is Dichropan T4 (which 
incidentally turns my surgical stainless tweezers a very nice matte 
black) but the Birchwood Casey brass black is also very useful at 
$7.60.  The Black command set screws I've dealt with have all been 
brass, so the latter is quite useful for touch up work.

http://www.brownells.com/Default.aspx

Lots of other things in there for the serious (or otherwise compulsive) 
radio restorer....

73,
Mike