[DeTomaso] Powdercoating Campi rims

[Mike Drew]

Excellent point!

What I meant, but failed to express correctly, is that to anneal them they heat them to full temp at the end of the day, then turn the heat off and allow them to cool down *inside* the insulated oven. This results in a very slow cool down, as opposed to just opening the door and letting them cool down in ambient temperature. 

Thanks for pointing that out!

Mike

Sent from my iPhone

On Sep 23, 2015, at 13:54, "Joseph F. Byrd, Jr." <byrdjf at embarqmail.com> wrote:

> I have had a little association with heat treatment techniques for other equipment, so here are my thoughts
> 
> The annealing process is the controlled cooling of the metal once it has been held at the relieving temperature for the specific time.  the concept of the annealing cool down is that you would like for the inside metal temperature to cool down before the outer (which is not going to happen).  So the next is to try and let both the inside and outside cool down the same.
> 
> If you allow the outer to cool quicker, the thermal contraction of the outer layer over the thermally expanded inner core will cause the outer layer to stretch.  This will put mechanical stress in the outer layer (or worse cause it to crack).
> 
> So I would be against a process where there was multiple heating and (uncontrolled) cooling as this would be like working the paper clip back and forth (work hardening) and increase the chance of cracking
> 
> It is not the fact it cooled "over night" , but the need is for a slow, Controlled cool down ( I have not researched what that rate would be for Mg.
> 
> -----Original Message-----
> From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of Rob Dumoulin
> Sent: Wednesday, September 23, 2015 15:45 PM
> To: 576103; Pantera - DeTomaso Mail List
> Subject: Re: [DeTomaso] Powdercoating Campi rims
> 
> Would it do the same result if he insists on heating them multiple times rather than one time with an overnight cooling?
> 
>