[Boatanchors] Porcelain spreaders

[mikea]

On Fri, Feb 02, 2007 at 08:49:22AM -0500, david knepper wrote:
> I am going to build an open wire feeder systems using 6 inche procelain 
> spreaders that were made by E.F. Johnson.  However, the ones that I have are 
> "coated" or embedded with soot particles after being part of an older feeder 
> system.  I suspect that the feedline was near a chimney.    They are not 
> bright and white like some others that I have.  I dunked the spreaders in a 
> solution of Clorox and Tide overnight and with some scrubbing with a 
> toothbrush, the results were less than satisfactory.
> 
> Should I have used my wife's dishwasher? or ???
> 
> I am sure that their insulating characteristics are fine but still would 
> like to try another cleaning approach before I build the feeder system.

I think the dishwasher will work fine, with a caveat or two: 

if there are unglazed spots or areas in the porcelain, water will soak
into the underlying material, and using the dishwasher's hot-air dryer
may -- I say, *MAY* -- do bad things, such as cause bits of porcelain 
to spall, if the air temp in the drying phase is over 212°F, due to 
steam generation down inside the porcelain when the absorbed water 
boils. My dishwasher's manual cautions users about this, and I've lost 
a few coffee cups to it. 

So I'd run 'em through the dishwasher's wash and rinse cycles, then 
air dry them or dry them in an oven at 150°F or so. A box with two 60W 
lamps ought to do just fine.                            

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin