[TheForge] Temper colors

[Bruce .]

Considering the tiny amount of oil you use on a blade, you can use any
non-toxic oil you prefer.  For example, one does not want to ingest a lot
of mineral oil, but there would be no harm in using it to finish a blade
because the tiny amount that would come through in the food would cause no
harm.  The same is true for petroleum jelly or even paraffin wax.  Note
that I am not advocating the use of these materials for protecting a blade,
but am just commenting they'd do the user no harm.

As for vegetable oils, there are basically three types:  saturated,
monounsaturated, and polyunsaturated.  Saturated oils, which include lard,
coconut and palm oils, as well as fully hydrogenated vegetable oils, won't
"dry" (in the sense of paint drying).  Unsaturated oils can dry, but
sometimes won't depending upon the total composition of the oil.

It's been said here before, but is worth repeating, that what is sold in
stores as "boiled linseed oil" (a classic drying oil) should never be used
on items for food-contact.  It really isn't boiled at all, but rather a
drying agent is added to it, and that agent often contains a toxic metal,
such as cobalt.

I have read that non- (or low-) toxic metals like iron can be used as
drying agents, but know nothing about it.

I believe that  polyunsaturated oil that has been "boiled" (think, "heated
till it fumes or smokes") will dry fine, based upon my experience oiling
ironwork and heating it to cure it.  However, ordinary polyunsaturated oil
will turn a deep brown when heated (say, 350F for an hour) that looks shiny
black on black iron, but which may be unacceptable for your beautiful knife
blade.  I don't know whether this is also true if you simply heat the oil
and then apply it -- as I've never tried it, myself.

Bruce
NJ


On Fri, Jan 10, 2014 at 12:14 PM, Ron Childers <ron at munlaw.net> wrote:

> For the difference in price it is doubtful the steel cares what the olives
> do in their spare time. Generic store brands are much cheaper and mixing
> with bees wax makes for a nontoxic preservative. I've heard it is
> essentially the same as Bore Butter. Some of our chemists can probably fill
> in the blanks ..
>
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net [mailto:
> theforge-bounces at mailman.qth.net] On Behalf Of martin marks
> Sent: Friday, January 10, 2014 10:23 AM
> To: Blacksmithing List Sponsored by ABANA
> Subject: Re: [TheForge] Temper colors
>
> I am so glad I have you guys to ask these questions. I put some extra
> virgin olive oil on it yesterday before I gave it to my friend. He was very
> happy with the work. Thanks again for the advice. I will get some good oil
> for my shop so I can apply it as soon as I'm finished buffing.
> --------------------------------------------
>
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
>
> TheForge mail list group photo site is
> http://www.shutterfly.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>