[DeTomaso] Stress-relieving Rims

michael@michaelshortt.com michaelsavga at gmail.com
Sun Aug 18 07:49:00 EDT 2013


The only thing I would offer is that I would sandblast them first (removing
baked on old paint versus just old paint) , then heat treat ( no evidence
to support it, but heat treating naked wheels sound more effective than
psinted ones) and lastly powdercoat with color and again with clear instead
of paint.

Michael Shortt
On Aug 17, 2013 10:23 PM, "Stephen Nelson" <steve at snclocks.com> wrote:

>  I searched again, this time under "annealing magnesium".  Found two
> relevant articles - which suggest J. Deryke is pretty much spot on in his
> recommendations for stress relief.  If interested check out:****
>
> ** **
>
> First Article<http://news.alibaba.com/article/detail/metalworking/100188588-1-metals-knowledge%253Apractical-heat-treatment-magnesium.html>
> ****
>
> ** **
>
> Second Article <http://www.keytometals.com/Article93.htm>****
>
> ** **
>
> Note, annealing temperatures are quite a bit warmer than the 375F he calls
> for, but that is not what we are going for – we want stress relief.  Here
> is a table from the ASM handbook on annealing temperatures for wrought
> magnesium alloys.  The previous two articles also reflect higher annealing
> temperatures:  ****
>
> ** **
>
> Annealing Temperatures<http://www.asminternational.org/pdf/HTSRefCharts/OMM051508.pdf>
> ****
>
> ** **
>
> Which means I will now be annealing my rims, then sandblasting them and
> refinishing.  So, next question.  I suspect I will end up spraying them
> myself to get a good seal on the metal.  Any recommendations on materials
> to use?  It sounds like they originally had a zinc-chromate prime – and I
> have some self-etching zinc-chromate primer – so suspect that would be a
> good base material.  Providing it is compatible with what ever would make a
> good finish.****
>
> ** **
>
> And, yes, I could get them powder coated.  But, so far, the powder coaters
> I have talked to are not aware of any special requ’s for magnesium and
> don’t sound crazy about long cooling times…****
>
> ** **
>
> ** **
>
> Stephen Nelson****
>
>  ****
>
> ** **
>
> ** **
>
> -----Original Message-----
> From: detomaso-bounces at poca.com [mailto:detomaso-bounces at poca.com] On
> Behalf Of JDeRyke at aol.com
> Sent: Saturday, August 17, 2013 3:59 PM
> To: michaelsavga at gmail.com
> Cc: detomaso at poca.com
> Subject: Re: [DeTomaso] Stress-relieving Rims
>
> ** **
>
> In a message dated 8/17/13 1:38:58 PM, michaelsavga at gmail.com writes:****
>
> ** **
>
> > Please send your methods so we can all do it.****
>
> > ****
>
> Piece of cake. I've published this several times before, in both POCA pubs
> ****
>
> over the last 15 years, but....****
>
> ** **
>
> * Preheat Mom's oven to 375F degrees some evening; take a clean, dry rim *
> ***
>
> with no valve stem or center logo disc and put it in the oven. If the rim
> is ****
>
> not clean & dry, there WILL be smoke and smells which will not gain points
> ****
>
> with the cook or the dog. Soap & water works just fine to clean Campys but
> be ****
>
> sure the rim is dry. If the valve stem is left on, the heat will badly ***
> *
>
> deteriorate rubber stems and the rubber grommet on metal stems. Leaks will
> ****
>
> follow.****
>
> * Bake for at least 2 hrs. Less time probably doesn't do as much while a *
> ***
>
> little longer doesn't hurt. ****
>
> * Then remove the rim (gloves!) and wrap in a non-synthetic-fiber blanket
> ****
>
> and PUT IT BACK INSIDE THE HOT OVEN. Turn off the oven and let it alone
> until ****
>
> Morning. The idea is, at least 2 hrs of 375F heat followed by as slow a **
> **
>
> cool-off as possible! ****
>
> This WILL cause stock Argent-Silver paint (or others) to turn tan. So have
> ****
>
> a rattle-can ready along with a new metal valve stem. It will do nothing
> to ****
>
> powder coated rims unless they have an overcoat or touch-ups of regular
> paint****
>
> . ****
>
> ** **
>
> Some owners contract with powder-coaters to coat cleaned, previously ****
>
> weld-repaired rims, then do a very slow cool-off in the power-coat oven as
> above. ****
>
> Most powder coaters run about 350F- 375F to cure their coatings, so if ***
> *
>
> they'll give you the slow cool-down afterwards, you get most of the
> annealing ****
>
> service simultaneously. ****
>
> This is one of those mods where, if things work according to Plan A, ****
>
> nothing will happen, so it's diffcult to quantify as an
> improvement/upgrade. But I ****
>
> suggest doing it every 10 years or so; I've heard of quite a few broken **
> **
>
> Campys in my 33 years with these beasts but none in the 1st 10 years of **
> **
>
> ownership, so I'm guessing on the safe period. Good luck- J Deryke ****
>
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