Rust removal or De-rusting

DERUSTING – THE EASY WAY by John Birrell

For members not using the electrolytic method of removing rust from iron and steel parts, here’s the information necessary to set up. This method was demonstrated at the Feb. Workshop Night.

You will need:-

A container large enough to suspend the rusty bit(s) without them touching the sides or bottom.

A packet of Washing Soda from the supermarket

A 12 volt battery charger – 4 or 5 amps rating is plenty

Metal for the anode (the liner inside the plastic container)– zinc flashing, stainless steel or plain steel. Not necessary if you use a metal container. This does, however, require the parts to be hung from an insulator, eg plastic pipe

Wire to hang the parts from a rod or pipe above the container. They can’t touch the anode or the metal container.

Water straight from tap or tank.

 

Fill the container with sufficient water to cover the parts. Add Washing Soda at the rate of about a handful per 10 litres of water. It’s not at all critical.

Connect the POSITIVE (Red) charger lead to the anode or direct to the metal container. Connect the NEGATIVE (Black) charger lead to the wire(s) holding up the parts. The above is critical! Note that the hanging wire(s) must make good electrical contact with the parts, or nothing will happen. Turn on power.

Leave for 24 hours or more (It doesn’t matter how long you leave the parts in – only the rust will be removed, not the parent metal)

The parts will come out with a black slimy coating which comes off easily with a pressure cleaner for large bits, or under a tap with a wire brush for small ones.

It pays to dry and prime paint the parts as soon as possible – they come out so clean that surface rust will immediately start if left damp.

 

SAFETY – Even though it is only 12 volts, you are working around water. Only switch on after all is in place, and remember to switch off before taking parts out.

The following is very important:- The process gives off hydrogen gas as the water is slowly consumed. Make sure that your set up is in a well ventilated space and avoid using angle grinders in close proximity. The frothy bubbles on the surface do explode when grinding sparks reach them. Learned from experience!!

 

It is easy to scale this process up to suit large parts. I have successfully treated telephone poles by building a dam from timber sides lined with Forticon plastic, and using a larger power supply to get more current. Once you have used this method you won’t want to know about molasses baths!

 

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