Got 2 old Optimus 300. I have tried a lot. but do I have to remove this mechanically. I have tried vinegar and fine steel wool with no luck, Any help is appreciated. Tom
Lye/sodium hydroxide is the best for cleaning nickel... It will eat anything organic, including your skin so care must be taken. One must also mix add the lye to the water, not water to the lye to avoid an exothermic reaction. I use a 1/4-1/2 cup to gallon of water.
Its hard to tell from the picture if it is corrosion, contamination or some old coating that has started to become unsightly. You might want to check if any paint strippers or acetone will do anything to it. Of course, lye too, as what Toby mentioned.
@MYN @Toby Garner Thank you for your reply. I have also tried paint remover to no avail. Now I want to try with sodium hydroxide. With caution. I think it is what is called Caustic Soda in Denmark. Tom
You could try a short soak in citric acid solution and see how that goes. I've found it very good at removing a range of oxidisation. It works well on both brass and rusty steel so it might be good for nickel. An alternative is to make a wallpaper paste solution with added citric acid powder/crystals. This can be applied directly to a tank as it's got a gloopy texture and sticks to the surface. Test the surface regularly with extremely fine wire wool and it should clean up nicely. (The recipe for the wallpaper citric acid solution can be found on CCS - search for Georges Stove Restorer or GSR)
@ColinG Thanks for your reply. I have just finished the cleaning and have used Citric acid. It removed 90% of dirt and ir. I tried sodium hydroxide first, but it had no effect. Citric acid for 10 minutes is the solution. 4 tablespoons in 4 liters of boiling water and a little washing-up liquid. Tom
Then it was certainly oxidation. Solvents and alkalis such as lye(caustic soda) wouldn't have much effects on oxidation, except superficially cleaning it for further treatments. Acids would be the usual solution. Actually, I believe vinegar would still have worked if you leave it in for long enough(at least a couple of days). That's because vinegar(diluted acetic acid) is among some of the weakest acids for such tasks. Citric is considerably stronger. Oxalic acid even more so. Phosphoric would be some orders stronger than citric and oxalic. With hydrochloric(muriatic) acid, you'd see instant results but that'd likely be too harsh and you wouldn't want it to be too fast or things would quickly get out of control.
Yes citric acid did the job. And what I thought was an Optimus is a Petromax 826 and there is already light in the lamp. Thanks for the answer Thanks. Tom @MYN
With regards to hydrochloric acid, there is a cleaning product in the UK called Harpic Power Plus Max x10... It contains a small percentage of Hydrochloric acid and it gets to work instantly on contact. The trouble is, its so fast its almost uncontrollable and although i have used it, I dilute it a lot. However, if you are faced with very stubborn corrosion, it will work, but I would think twice before using it on anything valuable or irreplaceable! The great thing about citric acid is that it doesn't cost much and its readily available. Below is a link to a thread about Harpix Max x10 New uses for Harpic PowerPlus Max x10
On an extreme end, I did use some home-brewed and very nasty stuffs for brass oxidation removal in the past. It was certainly not one of those usual chemicals we'd rather use here and not any that you'd find off the shelves anywhere. Nevertheless, it worked almost like magic. The following was what I shared here as a demo on its effectiveness:- How I clean my brass without elbow grease.
