From: Fred Martin (mung@in-touch.net)
Date: Thu Sep 30 2004 - 21:04:18 PDT
Everette...I believe the steel your trying to think of is Damascus wire
twist...where wire is wrapped around a mandrel of the proper size and
then maybe heated and the wire forge welded together to make a solid
piece. Does this sound like what you were thinking? I'm only guessing as
to the proceedure to make it. Fred Martin
everette wrote:
> Mr. Fareber wrote
>
> """""
> I don't want to be rude, but when and where has a failure of springs been
> caused by media blasting? I did 6 sets of springs with al. oxide and had to
> cut some serious scale. Never a problem.
>
> I would like to know of real world failure of metal (on our scale... MVs)
> caused by media cleaning or hydrogen emrittlelment.
>
> By reading this discussion, all my MVs should shatter into pieces when I hit
> a bump due to cleaning with media and rust prevention with phosphoric acid.
>
> Pls. provide proof (and not some lab experiment or some yahoo eating 2/3rd
> the way through metal with abrasives) that these things are actual concerns.
>
> Or is this list full of old wives and their old wives tales """
>
> Hydrogen emrittlelment.is a scientific fact, no discussion necesssary-- it
> just happens.
>
> I once put a throttle spring into dilute Hydrocholoric acid --. left for
> 1/2 hour or less, spring was clean, rinsed it off and painted with primer
> paint. Spring had been taken off when carburator was removed, and dropped
> in acid to clean oil and grease off it. When stretched to reinstall, it
> broke as soon as it was pulled on.
>
> I had an accident in 3/4 ton 4WD pickup that from factory had single leaf
> front springs, accident caused one spring to bend. The company I was
> working for at the time was big enough that they were self insured. There
> was a complete inspection of truck before repairs were authorized. The
> fellow who did inspection made specific instructions for repair of truck, he
> specificaly said that replacement spring must be new from GMC, not from
> salvage yard, and could NOT be media blasted, acid or caustic dipped. He
> further said old sping must be torch-cut into three pieces.
>
> And to address scale on metal - this is not something that falls out of air
> and attaches to metal. Scale -rust- is metal that has been disolved by
> chemicals in the surrounding air, or something that has gotten on metal
> some other way; and this caused chemical structure change that creates
> scale; hence if you take scale off, aside from embrittlement the remaining
> metal is thinner than before scale showed up. I am reasonably sure that
> springs are over-built and minor rust damage is acceptable. But there is no
> doubt that anything done to them will affect performance.
>
> Embrittlement can be compared to the effect on metal by prolonged hammering,
> much like swords were made by hammering a thick piece of steel until metal
> lost much of the impurities that were in it when made before steel makers
> learned how to make steel without so many impurities. There is a name which
> escapes me for shotgun barrels made by hammnering thin strips of steel
> together around a madrel until desired design of barrel is arrived at,
> another example of metal structure being changed
> by mechical means.
>
> I do not mind being considered an 'OLD WIFE" or even tale of old wife, I
> had much rather err on side of caution than to consider myself smarter than
> people who have the responsibitly of metalurgy design.
>
>
> Sorry to have made such a long post but I have been involved in the
> manufacture of chemical cleaning products both acid and base for several
> years.
>
> Everette
>
>
>
>
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