Re: [CAD_CAM_EDM_DRO] RE:re:Re: cast iron

Hi Ballendo,

I must say that most of the castings that I machine are for high and very
high precision and I tend not to want to rush and ruin.

> What about the 'accelerated' aging? I didn't mean to imply that the
> box (refrigerator/icebox) would get very hot. It seems that
> if 'natural aging', which as you said, relies on the weather, will
> work well; then a faster Day/ night cycle might be created. Something
> based on the time for the casting(s) to reach the high, then the low
> temp. (which would save time as long as the castings weren't so large
> as to take a "days' worth" of time to cycle)

With weathering in this country we have a fluctuation in temperature in the
order of 5-10c in a twenty four hour period. On top of that winter average
temperatures can go as low as -10c with the summer ones up as far as 30c.
The use of "Green House" ageing speeds up the process from over a year to
three months. I cannot comment if your idea will work, as I haven't tried
it, but I wonder if there would be enough time between hot and cold cycles
on the thicker sections to make the expense and, possibly, shorter time
worth while.

In short putting the castings under glass and using the sun is virtually
free. A refrigeration and heating unit would cost a lot to run.

> I used to work extensively with wood, and the equivalent there
> is 'air dried' vs. 'kiln dried'. The Kiln group always said, "There's
> NO difference, IF the kiln process is done correctly!" But using
> hand tools, I could ALWAYS tell the difference. For SOME things the
> difference 'mattered'; for many things it did not.

I too notice the difference as most of my woodwork these days is for pattern
making, as I am trying to do this with CNC, this is the reason I looked and
found this list.

> So maybe the BEST procedure is Shake, Bake, AND age! But what about
> the "good enough" that many of us will be looking for?

I can see that a combination of sonic ageing and weathering may well get you
the results you require but until it is proved I'll go with my way of
working certainly for my one off irreplaceable castings.

Terry