Posted by Jay B. Good on Tuesday, June 28, 2005 at 10:20PM :
In Reply to: rust removal that really works posted by Bruce in wet and snowy Sechelt on Tuesday, June 28, 2005 at 8:32PM :
Found this with search engine
DERUSTING
(By Kevin Brown)
As all restorers know one of the most irksome and destructive tasks is derusting iron and steel fittings. There are many methods includ-ing sandblasting, bead-blasting and the time honoured molasses treatment. There is an-other method involving electrolysis. Recently I stumbled on the process in an article in an old English "Model Engineer".
To set up you will need:
(1) A good sized plastic container
(2) Water
(3) Washing soda (I get mine from Woollies)
(4) A battery charger or other source of DC power, the more grunt the better.
(5) Some scrap pieces of iron preferably marine grade stainless steel.
Method: For every gallon of water (4 ½ ltrs) mix in 1 lb (450 gms) of washing soda. The brand I use is called Lasting Earth. I started out using a baby-bath and six gallons of water but now use a plastic drum containing approx. 30 gallons. You will need to keep topping this up from time to time.
Now suspend your work in the middle of your container using welding wire or any other clean steel wire. Around it on either side but definitely NOT touching, suspend your scrap also using steel wire. Now hook up the NEGATIVE terminal of your DC power source to the steel wire attached to your work. Then hook up the POSITIVE terminal similarly to the scrap (or sacrificial plates). Switch on the power.
Pretty soon you will see heaps of tiny bubbles coming off pretty well everything in the water solution. This is hydrogen, so if you smoke, don't. The hydrogen is liberated off the sur-face of the metal and so loosens all the rust, paint or other goo adhering to your precious part.
Depending on how much grunt your DC source has (mine works at 12 volts 8-10 amps and could be a lot larger), and if you leave the system to work overnight, in the morning the rust will be a black sludge and can be easily wire brushed off your part. If still not totally clean, put it back for more treat-ment. Even the most rusted pieces will clean up to shiny grey iron again.
This process will, not damage your work in any way (unless of course you hook the work up to the positive instead of the negative lead. You can put your hands in the water even with the system running providing you don't touch a negative or positive part at the same time.
I have been using the same water (topped up) for six months or so now and don't think the washing soda has an expiry date. This stuff, by the way, is the same soda that occurs natu-rally in all the soda lakes in Africa and South America etc. where you see all the birdlife, flamingoes, ducks, storks etc. as well as crocodiles and hordes of fish including Nile perch. So it is environmentally friendly.
Follow Ups: