JD and Zolo,
Citric acid seemed to be one of the main components of
the over the counter flushes for radiators.
I tested a citric acid monohydrate against the
aluminum foil for a week before trying it in the
radiator.   The molecular weight of the monhydrate was
200.   40 grams /liter or 160gram/gallon or 320gram
for two gallon(for the job) will yield a .2M liquid
with a pH somewhere between 1 and 2.   I used 2
gallons because I was trying to do the big pipes as
well but would use caution if you still have the metal
pipes.   You have to remove and replace the corks to
displace the water with the citrate solution so wear
some eye protection if you do this.
Citric acid is considered a weak organic acid.   There
are several forms of it so check your molecular weight
to see that there is no major difference.   If there
is a big difference you need to adjust the amount you
use and perhaps check the pH.   If all else fails just
ballpark the amount and do the foil check.
   As for a source I would consider a high school if
you are unable to find it at the harware store or
online.   The cheaper the better.
               gary
--- "John D. Foster" <jidd@jiddware.com> wrote:
> Hey Gary,
>
> Being several years out of my high school chemistry
> class, could you refresh
> me on how to achieve a 0.2M concentration?  As
> chance would have it, I have
> several pounds of citric acid on hand as my wife is
> starting an
> aromatherapy/bath product business and its one of
> our raw materials.
>
> Thanks,
> JD Foster
>
>
> >    A 0.2M citrus acid enemia is a good idea if you
> are
> > running a bit hot.   Isolate the radiator at the
> big
> > pipes and flush with hot water.   Soak the
> radiator
> > for a week with the enemia and flus with hot
> water.
>
>

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