Hi,
OUCH! OUCH! OUCH! (Better than writing BS.)
A finely ground silica is in many ways more dangerous as it is readily made into an "aerosol" and thus goes deeper into the lungs.
The "Mors hardness" is not the issue - the salesman is giving the professon a bad name.
To save all from a diatribe, I'll let you look up and study what silica and silicates can do to the lung.
Yes, we all use dangerous products – heck, we transport tens of thousands of gallons of gasoline through city streets every….second…
So, use the parting compound BUT wear an approved mask. As you won't be using the stuff day-in & day-out, you will be with us a very long time - we hope.
Kind regards,
DBN
--- On Tue, 3/1/11, Richard <richardrigel101@gmail.com> wrote:
> From: Richard <richardrigel101@gmail.com>
> Subject: Re: [gingery_machines] Re: Calling Chemistry intelligentsia : Parting powder specs
> To: gingery_machines@yahoogroups.com
> Date: Tuesday, March 1, 2011, 9:48 AM
> OK, thanks Guys, I've certainly
> learnt a lot on this subject that I never I
> didn't know!
> Back to the sales pitch that I got from the salesman who
> maintained there
> was absolutely no health risk involved (and yes, I will
> still wear a mask).
> But if it is 60% silica then it does pose a health risk. To
> which he said
> yes but it is ground so fine that it is technically soft
> and on the hardness
> scale it reads "Hardness (mho) 1.0" where diamonds
> are 10.
> I'm still a little undersided about that. I would have
> thought that silica
> causes irritation to the lungs irrespective of granular
> size?
>
>
> On Wed, Feb 23, 2011 at 4:23 AM, Carlos Contreras <maximo64@yahoo.com.mx>wrote:
>
> >
> >
> > You are right Bill,
> >
> > the stearic acid is a "non wetable" material produced
> mainly from animal
> > fat,
> >
> > the not wetable pproperty or in other words the
> property of water repelent
> > is the key in the recipe.
> >
> > All the best.
> >
> > --- El mar 22-feb-11, oldstudentmsgt <wmrmeyers@sbcglobal.net>
> escribió:
> >
> > De: oldstudentmsgt <wmrmeyers@sbcglobal.net>
> > Asunto: [gingery_machines] Re: Calling Chemistry
> intelligentsia : Parting
> > powder specs
> >
> > A: gingery_machines@yahoogroups.com
> > Fecha: martes, 22 de febrero de 2011, 21:50
> >
> >
> >
> >
> > Things I've seen as parting dust in older foundry
> books:
> >
> > plumbago (graphite powder)
> > wood flour (find sawdust)
> > fine sand (silica dust)
> > sea coal (not sure what it is, but except fine coal
> dust...)
> >
> > and have used dollar store talc-based baby poweder,
> which works well for
> > aluminum, at least.
> >
> > the recipe Carlos provided sounds good. Now I have
> either remember or find
> > out what stearic acid is... Seems like something I
> should know... soap? No,
> > according to Wikipedia, it's a byproduct of
> hydrogenating animal fat, or
> > certain vegetable oils. Based on tallow.
> >
> > http://en.wikipedia.org/wiki/Stearic_acid
> >
> > HTH!
> >
> > Bill in OKC
> >
> > --- In gingery_machines@yahoogroups.com,
> "Brite" <coldtoo2000@...> wrote:
> > >
> > > No help w/ your chemistry, but you can use also
> baking soda for parting,
> > among other things.
> > >
> > > CT2
> > >
> > >
> > >
> > > --- In gingery_machines@yahoogroups.com,
> "Richard" <richardrigel101@>
> > wrote:
> > > >
> > > > Greetings all, after an extreme search for
> PP I seem to have finally
> > spoored up a non carcinogenic one. For various reasons
> I'm above average
> > paranoid when it comes to my lungs and the search for
> even ordinary silica
> > based PP has been exhaustive.(Anybody actually know
> what High Temperature
> > plastic flour is?)
> > > > The salesman assured me many times that this
> particular product has no
> > health issues related to it, Would someone with a
> smattering a chemical
> > learning please look over these specs and let me know
> if this is so.
> > > > With thanks
> > > >
> > > > TALC POWDER Grade : T 10
> > > >
> > > > MINEROLOGICAL COMPOSITION
> > > >
> > > > Talc 98% Calcite <2%
> > > > Free from Asbestos, Quartz & Tremolite
> by XRD Analysis
> > > >
> > > > PHYSICAL DATA
> > > > Whiteness compared to MgCO3 92%
> > > > Oil Absorption G.Oil/100g 42 pH 8.7
> > > > Matter soluble in water 0.07%
> > > > Specific Gravity 2.8
> > > > Hardness (mho) 1.0
> > > > Moisture at 105 degree C 0.01%
> > > >
> > > > CHEMICAL ANALYSIS
> > > >
> > > > SiO2 59.9%
> > > > Al2O3 2.1%
> > > > Fe2O3 1.2%
> > > > CaO 0.9%
> > > > MgO 30.6%
> > > > LOI 4.8%
> > > >
> > > > PARTICLE SIZE
> > > >
> > > > Top Cut 15 Micron Average Particle Size 3
> Micron
> > > >
> > > > Distribution
> > > >
> > > > < 15Micron 97.%
> > > > < 10Micron 87.%
> > > > < 3 Micron 51%
> > > > < 2 Micron 36.%
> > > >
> > >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
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