[TheForge] oil temps (one more time)

[Bruce Freeman]

Although I think Andy is right with respect to the universe of
businesses he's speaking of, I STILL think the way to go is "cheap
tool first".  If you never explore the use of the cheap tool, you'll
never know when it will do essentially an equal job for you as does
the expensive tool.

Furthermore, as a chemist I'm highly suspicious of any
"high-temperature oil."  In the past, such things have been
halogenated --  i.e., brominated or chlorinated.  Such halogenated
"oils" can be quite toxic and environmentally unfriendly.  They have
polluted the entire world to a greater or lesser degree.  I suggest
that before anyone brings any "high temperature oil" into his shop he
read the MSDS and assure himself he is not dealing with any such
halogenated material.

Vegetable oil might not be the "best" quenching oil, but it's cheap
and non-polluting.  So what if it goes rancid?  Rancidity won't hurt
the quench.  I seriously doubt you'll see any significant change to
the physical properties anytime soon.  And when you do, take the 5
gallons of oil and turn it into soap for your shop, and buy another 5
gallons of fresh oil.

On Sat, Nov 20, 2010 at 10:56 PM, Steve Bloom <smith at blacksmithing.org> wrote:
> At 06:27 PM 11/20/2010, James Binnion wrote:
>
>> > [snip]As you heat them to extreme temperatures over
>> > prolonged time periods they are going to change structure from
>> > oxidation and evaporation etc and you will have a different oil than
>> > when you started. I don't really know what all the changes would do
>> > but I bet you will have to change oil fairly often. [snip]
>
> and then Andrew Vida  chimed in:
>
> [snip]spend the money and get the proper tools for doing the job.[big snip]
>
> While all of this may be true -- I'm in the 'proof-of-concept' stage.
> Based on my experience with 1050 & 1065 and water-quench using a
> partial clay coat, cracking is a distinct possibility. To forestall
> that, normalization, even heat for austenization, warm water quench
> and a tempering bath with rapid heat  transfer is the target.  Since
> I don't want to make a 36" long hot salt bath, I'm exploring using
> oil as a tempering medium - not for quenching.  The oil  will go bad
> eventually but it is not being exposed to anything that a deep  fryer
> doesn't hand out. If there experiment works out, then the
> higher-priced  spread might be worth exploring. Realistically, we're
> talking about a
> couple of times a year use to make what will be effectively a
> non-commercial item, so it's 'dipping-the-toe-in-first'. With the $24
> for oil, I'm into the oil bath for probably $35 and my time - and
> since I'm gainfully unemployed (retired), time I have.
>
> I appreciate the comments (well, some of them <grin>) and will post
> results as they happen.
>
> Steve
>
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-- 
Bruce
NJ