Summary for measure rusting rate Discussion
Rusting rate measurement is best handled by weighing a standard coupon before and after exposure, then reporting corrosion as weight loss per area per time. In response to Aleks Lazarevic’s idea of dissolving rust and titrating iron, Ken Vlach said titration is problematic because both Fe(+2) and Fe(+3) may be present. He recommended removing the rust and re-weighing the metal instead, citing ASTM G1-03, which includes cleaning methods for corrosion test specimens. Ken also noted that a practical rust remover is a hydrochloric acid solution with an inhibitor, since the inhibitor helps prevent loss of base metal during cleaning. When Aleks later asked where to find rust-removal substances, the thread suggested a household product such as C-L-R (Calcium-Lime-Rust Remover), whose label lists water, glycolic, sulfamic, and citric acids plus surfactants.
Q. Hello I am doing a experiment and I need to measure the rate of rust. I was thinking if I dissolved the rust then tried to find the amount of iron ion in solution however I do not know how to dissolve the rust or what chemicals I should use for the titration.
thank you
ALEKS LAZAREVIC
STUDENT – BRISBANE, QUEENSLAND, AUSTRALIA
2007
A. Titration for iron is problematic since both Fe(+2) & Fe(+3) will be present.
Weigh the sample coupon (a thin rectangle of some standard area is usually used) before testing. Afterwards, remove the rust & re-weigh the coupon. Corrosion can be reported in units of weight/area/time.
ASTM G1-03, ‘Standard Practice for Preparing, Cleaning, and Evaluating Corrosion Test Specimens’ gives some solutions for removing rust. It is probably much more practical to use an equivalent household rust remover; e.g., hydrochloric acid solution containing an inhibitor. The inhibitor is necessary to avoid loss of metal.
Ken Vlach [deceased]
– Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
Q. Where can I find the substances used to remove the rust?
ALEKS LAZAREVIC [returning]
STUDENT – BRISBANE, QUEENSLAND, AUSTRALIA
Ken recommended a household product, so try C-L-R
⇦ on
or
Amazon [affil link]
(Calcium – Lime – Rust Remover). The label says it contains water, glycolic, sulfamic & citric acid s, and surfactants.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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