[ginda]

Hello all

Hope someone will be able to help me. I am using an off the shelf rust remover to etch steel/high carbon steel. The rust remover I am using works quite well but i have noticed that after several minutes there is a build up of something on the surface of the steel (Even when I keep brushing the liquid on), when I wash the steel with water and wipe down with cloth you can see a dark grey colour on the cloth and sometimes a light yellow colour.

The steel I etch is finely polished and has an even surface. I suspect this build up also affects the quality of the actual etch!

The rust remover bottle states the following - (Contains a.o.: non-ionic surfacants <5%. Contains phosphoric acid EINECS: 231-633-2. Danger H314)

Question 1 - What is this build up on the surface of the steel?
Question 2 - Whats the easiest way to remove this build up?
Question 3 - Are there any other off the shelf DIY alternatives that doesnt produce this surface build up?

I am from the United Kingdom.

Thanks in advance for any help

G

[Guitarmaniac86]

Question 1: Do not quote me on this but I was looking into rust removers earlier in the year and from the very basic research and reading I have done, the rust remover leaves a layer of iron phosphate particles on the surface to reduce the chance of rust from re-forming again. Some removers add a small amount of iron phosphate to reduce loss if surface iron and increase rust resistence.

I do not know if the iron phosphate will come off on the cloth, though I suspect it would. The light yellow colour might be some kind of iron oxide being removed.

Question 2: Water wash then dry it very well, then use isopropyl alcohol (rubbing alcohol) might help though. Some rust removers use isopropyl alcohol and 2-butoxyethanol though I do not know why the 2-butoxyethanol is used, though I think it is for dirt removal so all this should just wash/wipe away/evaporate away.

Question 3: No idea really. All rust removers I have come across contain phosphoric acid and surfactants.

[ginda]

Question 1: Do not quote me on this but I was looking into rust removers earlier in the year and from the very basic research and reading I have done, the rust remover leaves a layer of iron phosphate particles on the surface to reduce the chance of rust from re-forming again. Some removers add a small amount of iron phosphate to reduce loss if surface iron and increase rust resistence.

I do not know if the iron phosphate will come off on the cloth, though I suspect it would. The light yellow colour might be some kind of iron oxide being removed.

Question 2: Water wash then dry it very well, then use isopropyl alcohol (rubbing alcohol) might help though. Some rust removers use isopropyl alcohol and 2-butoxyethanol though I do not know why the 2-butoxyethanol is used, though I think it is for dirt removal so all this should just wash/wipe away/evaporate away.

Question 3: No idea really. All rust removers I have come across contain phosphoric acid and surfactants.

Thank you very much replying, what you have explained makes sense, I will give rubbing alcohol a try after my next etch and report how I got on

[Enthalpy]

I've had a rust remover based on hydrochloric acid. This one left a blank metal surface. Depending on your needs, the phosphated surface is useful as a standard means to prevent further corrosion.