tests have shown that this process is NOT safe for Zinc Die Cast Metal,
also known as "Pot Metal" Unless your goal is to dissolve the
pot metal, do NOT immerse those parts in Molasses!!
It is not clear what other metals may also be affected by this process,
so use caution.
rust using Molasses uses a process known as Chelating. Without a good,
scientific explanation, the process can be described as "Reverse
Oxidation", wherein certain acids or chemicals in the molasses solution
strip the oxygen from the Iron Oxide, leaving the iron behind. While I'm
not absolutely positive about what exactly causes the rust to be removed,
I am sure about one thing: It works.
process is slow compared with other methods; electrolysis, various other
acids, abrasives. Surface rust can be removed in a day or several, while
heavy rust will require at least a couple of weeks. However, there are
The ingredients are inexpensive. I purchased 5 gallons of feed-grade molasses
from the grain elevator yesterday for less than $9, and that included
a dollar for the container (because I didn't have one with me). This is
enough to produce 20-50 gallons of solution (usually 1:4 or 1:10 is used).
There are no dangerous chemicals. Unlike some of the other methods, there
is nothing that can burn your skin or eyes, and most other metals are
unaffected, by this method.
There are no toxic by-products. The solution can be used repeatedly, for
many months, but when it's time to dispose, you can safely pour out onto
the lawn, where the molasses and water will decompose naturally.
It's effective. All oxidation will be completely removed, given enough
time in the bath. The clean metal underneath will not be affected. For
heavy rust it will take longer, and certainly a wire brush will help remove
the large depsits, and help the process by allowing fresh molasses to
come into contact with the rust.
there are a couple of drawbacks. First, the process is slow. I've already
mentioned that, but if you have more time than money, it's a great way
to get rid of the rust on your restoration projects. Also, the Molasses
solution smells like molasses. Even worse, once the solution starts to
ferment, it will smell even more. I've tried using chlorine bleach to
prevent fermentation and mold, but was unsuccessful. It's possible that
the bleach evaporated out. I've read that people consider the fermentation
process necessary for the process to work good, but I doubt that's the
case. It will likely increase the acid level of the mix, but I expect
the regular solution to still be very effective regardless. I may try
the chemical that winemakers use to prevent fermentation in wines and
see if that is effective.
the parts will come out of the process with no protection from future
rust, and the oxidation will commence again immediately. You must be prepared
to clean the molasses from the parts, and protect the metal right away,
either by painting, oiling, or or other means, otherwise your parts will
quickly begin to rust again. I've soaked brake drums, heavy with rust
for a couple of months (forgot about them) and after washing them with
soap and water, they began to rust even before they were dry. Be ready
to protect your parts!
and your parts must be degreased completely, since the solution does not
cut grease, and the grease will prevent the solution from contacting the