Re: [EVDL] Brass & corrosion: how much is "normal"

--- [email protected] wrote:

> None of the corrosion you refer to is "normal" and
> it is almost certainly
> not brass. For sure the bolts in the transmission
> are not brass. It is unlikely
> that the vacuum pump housing is made of brass
> either. You don't say what
> type of pump you have. It may be made from
> electroplated ferrous metal, or from
> aluminum that has been chromated to a golden/brassy
> color.
>
> The bolts would be made from ferrous metal which
> would then electroplated
> with either zinc, cadmium, or an alloy of tin-zinc.
> After electroplating the
> bolts would be given a chromate coating which could
> look either bright and
> silvery, gold in color (often mistaken for brass)
> or black. There are others
> colors too, but those are the ones used most
> commonly in the automotive industry
> for electroplated parts. Olive drab is sometimes
> used, but more seldom.
>
> The electroplated coatings are used to keep the
> ferrous metal substrate from
> corroding. The secondary chromate coating is used to
> prevent the
> electroplated coating from corroding. It's a two
> step anti-corrosion process that works
> very well under normal conditions.
>
> If a bolt is going to be used to fasten a piece of
> aluminum, it HAS to be
> coated with either cadmium, or tin-zinc alloy. Very
> often cadmium or tin-zinc
> is color coded with the gold chromate. Zinc is not
> at all compatible with
> aluminum, and for that matter neither is brass.
>
> The chromate coatings are very thin. Polishing them
> would only remove the
> chromate coating and maybe even the electroplated
> coating. Then the parts would
> look bad again, but even sooner. Your best solution
> would be to replace the
> corroded bolts and try to prevent the sulfuric acid
> "mist" from occurring
> again.
>
> Those are just the basics, but it should help you
> decide on a course of
> action.
>
> Lawson Huntley
>
>
>
>
>
>
>
> ************************************** Get a sneak
> peek of the all-new AOL at
> http://discover.aol.com/memed/aolcom30tour
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


Converting a gen. 5 Honda Civic? For $20 DVD you can purchase footage of my '92 sedan, as well as a del Sol and hatch too!
Learn more at: www.budget.net/~bbath/CivicWithACord.html ____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering wheel? Are you saving any gas for your kids?



____________________________________________________________________________________
Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games.
http://sims.yahoo.com/

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

Click to expand...