<VV> Which way??

[Tony Underwood]

At 01:26 hours 12/29/2005, Jim Bannister wrote:
>Fellow Airvarians,
>
>I'm in the process of getting the moveable part of a LM center A\C vent
>rechromed.  This piece has little vanes that deflect the air slightly in one
>direction.  The question is: do they bias the air in the driver's or
>passenger's direction?  My center vent came in pieces so I have no way to
>know how it is PC (prototypically correct) I could care less about the
>political side of PC.
>
>
>
>I've gathered some knowledge about the rechrome process.  When the guy at
>the chrome shop looked at the piece he said that he couldn't make much of an
>improvement.  My piece was pretty crusty with lotsa pits 'n pimples.  He
>explained that each pimple in the chrome was actually a small divot in the
>metal below.  Not much he could do, he said.  I asked him if I could prep
>the piece. Eureka!!! The holy grail of rechroming.  Do it yourself prep.  He
>offered to strip the old chrome and then let me do the clean up.  I've been
>filing and sanding for some hours now and the piece is looking quite
>presentable.  I'll finish off on the buffing wheel, it shows every
>imperfection.  When I'm done, he should be able to lay down a pretty smooth
>layer of chrome.  We'll see.  The saga continues at a later date.  It looks
>to me that if you can find an accommodating chrome shop, it will be possible
>to salvage parts that otherwise would not be practical to redo.




It's worth chasing down a shop that will offer to do 
triple-plating.   TP chrome work is good for pitted stuff etc...  the 
first plating is copper.   This allows the easy filling (via solder 
etc) of the pitted areas, or if the copper layer is thick enough and 
the pits are small, the copper alone can sometimes fill sufficiently.

Solder filling of the copper coat if it's over plastic is 
tricky...  but there are very low temp solders available that can be 
flowed at ~350 degrees, some flux and a quick dab of this solder can 
fill a pit easily enough even over plated plastic without doing much 
if any damage to the base material.   There are also conductive 
paints containing powdered metal which can be used to fill pits, then 
replate and polish etc.

Sand/buff the copper to minimize the pits, then replate with another 
layer of copper, check again etc.   A coating of nickel follows next, 
then the chrome.   The nickel is waterproof, keeps the copper from 
oxidizing and causing peeling of the outer plating.   Chrome is *Not* 
water proof unless it's on damned thick.    First the copper, maybe a 
2nd coat to help cover the pits etc, then buff/polish, followed by a 
coat of nickel, then chrome which sticks to the nickel much better 
than it sticks to steel or pot metal etc.

This is the way they all used to plate stuff...  gives an outstanding 
finish that weathers well, and doesn't peel.    Now days, most places 
just dunk the work in the chrome vat for a few minutes and let it 
fizzle and fume then yank it and wash it, done.   Looks great for a 
while...  until it peels off after exposure to weather (read: 
moisture) for a while.    Remember, chrome is not waterproof, relies 
on the platings underneath to keep oxidation of the base metal from 
making the chrome peel off.   Shame...   good triple-plate chrome 
will last for a *very* long time in weather, too bad so few people do 
it anymore.


tony..