anti-corrosion coatings

[Nick HopwoodParticipant @nickhopwood71702]

I am trying to find an anti corrosion coating for mild steel. It should be non-chipping, preferably non toxic and preferably black or at least dark in colour. I have tried galvanising but it is expensive and needs more work when completed in order to remove drips and sharp points made during the galvanising process. The main consideration should be the rust proofing qualities. Many thanks for any help you experts out there can provide.

[Nick HopwoodParticipant @nickhopwood71702]

[KWILParticipant @kwil]

Can you explain the intended use, there is a world of difference between, say, preventing corrosion when indoors as opposed to at sea!

[JohnFParticipant @johnf59703]

Nick, depends on how anti rust you want the coating but gun blueing/blacking may be appropiate. gThis finish is resistans to rust but will not prevent it completely. I am not talkinh about the cold compounds but either the hot rusting process or the high temperature caustic blacking process.

Neither of these processes make any dimensional change to the component and are resistant to rusting in "normal" conditions but if left wet for a long time rust will take over !

John

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Phosphating .You could not do this yourself very easily but the process is widely available from plating firms and many general engineering firms . Dull grey , inert , rust resistant and long lasting .

[John Stevenson 1Participant @johnstevenson1]

Tuftriding.

Low temperature hardening process that puts about 10 microns of case on a steel product. It's black and the upshot is that it very rust resistant.

Local heat treat plant has a bucket of salt water in the passage way with some steel bars sticking out. Where they enter / leave the salt water there is a big rusty scab attached to the bar, but remove it and it wipes off leaving the bar pristine. This bucket has been there for about 8 or 9 years.

The scab is caused by all the crap and dust in the air settling on the top of the salt water and rusting

[Nick HopwoodParticipant @nickhopwood71702]

Many thanks for your replies. It would be used outside where there are farm animals but not in a particularly harsh environment and could be done commercially. I am used to gun blue and find it tends to rust if not oiled frequently so I don't think that would work. It does not matter if the dimensions are increased – it is not an accurate piece of machinery, it is used for feeding animals hence the non – toxic element. I'll make some enquiries about phosphating and low temp hardening. Thanks again.

[JasonBModerator @jasonb]

Sounds more liek you need powder coating or something like that

J

[Nick HopwoodParticipant @nickhopwood71702]

Thanks for that. I have tried powder coating but found it tends to chip. Might have to stick to galvanising!

[Clive HartlandParticipant @clivehartland94829]

Nick, why not research Zinc Electroplating, it comes out very smooth and clean and is a common industrial process.

Clive

[Jeff DaymanParticipant @jeffdayman43397]

You might look into urethane spray-on truck bedliner coating. It is almost indestructible when sprayed on steel, and totally corrosion proof. When cured, it is non toxic. It is flammable though, if exposed to direct flame, not sure if that is a concern.

One manufacturer I work with here has been using it extensively on things like ramps, gates and cattle stanchions for barn use with great success.

One brand in north America is Rhino Liner if you want to research it a bit.

JD

[Ian S CParticipant @iansc]

JD, the one I know is POR 15, another of my mates uses it when rebuilding trucks, and cars. Ian S C

[KWILParticipant @kwil]

Frost car restorer supplies, FROST.CO.UK sells POR 15.

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