I
f your mother has not yet forgiven you for the
electrolysis-bath de-rusting that we showed
you in the last issue, then her patience will
truly be tested with molasses-bath de-
rusting! This is slower but even simpler than the
cheap ’n’ easy electrolysis. The cost is comparable,
even on a large scale, as we will demonstrate here.
What is ‘molasses’? While molasses can come
from several plant sources, it is normally unrefined
sugar syrup derived from sugar cane. Unlike the
nasty refined white sugar that has been stripped
of nutritional value, this sticky black stuff is loaded
with natural vitamins and minerals — which
explains why it can be found in health-food stores
and animal-feed and produce stores. Somewhere
along the line, it was found to remove rust as well!
How does it work? We won’t bore you with
complicated science. No wait, yes we will — for
the inquisitive. The basic process is known as
‘chelating’. A quick Google search turns up the
following definition of a ‘chelate’: “A chemical
compound composed of a metal ion and achelating agent. A chelating agent is a substance
whose molecules can form several bonds to a
single metal ion.” The chelating agents contained
in molasses — cyclic hydroxamic acids — are
essentially why molasses effectively chelates iron
and makes it soluble.
In layman’s terms, the molasses turns the rust
into a gel that washes off with water and leaves a
phosphor-like protective coating. This works well
for mild steel and iron but not for other metals, so
don’t try it with aluminium, etc.(^108) themotorhood.com
WORDS AND PHOTOS:
ANDREW CLATWORTHY — STREETNEAT LTD
AS PROMISED, WE SHOW YOU MORE DIY DE-RUSTING SOLUTIONS AT BEER-
BUDGET PRICES — THIS TIME, WITH THE ADDED BONUS OF THE SMELL OF RUM!
STEP ONE
Don’t bother with buckets to do your molasses
bath unless you only have Meccano-sized
pieces of car to de-rust. These IBC 1000-litre
containers can be bought wholesale for as little
as $50 from most industrial depots. If Trade Me is
your thing, you will see them for $100 on dozens
of listings. Be sure to get ones that have only had
detergent in them! Simply lop the top off with a
cutting disc on a grinder and you’re away.
Tech Feature DIY Rust Removal