De-rusting

[reset]

Jenolite (Phos. Acid) is the best to me.  Can get thin stuff if immersion possible and gel for if not.  If parts go a nice even black then spray lacquer or shellac can look quite original.

Love getting chassis and parts plated, leave all the rust removal to the platers.  If bad you see some pits but thats patina if not its a great finish done in "old nickel" is what my guy calls it.





Gary

Looks like new!

[Kalee20]

I've not seen a mention of oxalic acid so far, but it's certainly good at shifting rust stains out of fabric. It does mobilise iron oxide by forming a soluble complex with the ferric iron.

It is rather poisonous, it's what makes rhubarb leaves thus, for instance, but with sensible precautions I've never had any issues using it.

I haven't tried it on really rusty steel, that's coming up sometime! I do have a container of phosphoric acid, and reading this thread it looks like I'll be getting some citric acid too, so lots of options available...

[Amie]

I'm just messing about here, but I have an old pre ww2 radio chassis (PYE) that I can't bring myself to bin, so seeing this thread I thought I'd do a few small test pieces, the first is a small pulley block dug up out of the garden, (it was so rusty it was unidentifiable), it has come up pretty well, but with a few patches of scale untouched.

The boiler guy said that the milder chemicals work fine just take longer, but for the incomplete cleaning soak and scrub in sodium carbonate firsthand to degrease as Cleggy suggested, then rinse, do your acid soak, then rinse and scrub in the soda again, then rinse... To protect I'm now thinking the surface could have phosphoric acid applied.

I don't know what would end up left of this chassis, but the finished is all gone and there is flaking rust in places.

[Radio Fixer]

I have had chassis bead blasted and along with phosphoric acid it makes a great surface to spray paint, as said above. Trouble was that later I couldnt find anywhere that would do the blasting bit for me.

Gary

[Amie]

Hi all.

My experiment at chemical cleaning is pictured. Of course I didn't think to do the "before" photo

   

It started out as a solid lump of rust but although now heavily pitted, it is free from all the rust and the pulley even turns.

So a big thumbs up for the method outlined in my last post.

[Kalee20]

That's impressive, Amīca

How much citric acid to how much water did you use?

[Amie]

Hi Petrus

I used 50g / 500ml ... Dissolved the crystals in hot water, then stirred occasionally. Took 24 hours to get that result.

Degreased before, and cleaned and neutralised after with sodium carbonate.

[Kalee20]

Thanks! I'd played safe and ordered 5kg from the Bay of E earlier today...

Looks like there's going to be plenty left over, so I can make some sherbet

[Cleggy]

Depending on what the job is, you can vary the concentration and temperature with citric acid; what's good for some really hefty piece of metal won't be optimum for a delicate radio part.

As above, it does have the advantage over oxalic of not being toxic, and you can buy it on the High Street; my local Wilko's always has it.

I've been trying to convince myself as to whether or not brushing citric solution on to really thick heavy rust (possibly on something not easily immersed), and leaving it overnight "softens" the rust up and makes it easier to remove by a wire brush on a power tool? Hard to say whether this is real or the "placebo effect"   . I really hate rust dust!

[Freya]

Use molasses, tried it myself for the first time with very impressive results. Best if you can get from farm supplies as its cheaper than health food stores. 1 part molasses to 10 parts water. Be prepared to dry thoroughly when the parts come out as they will begin rusting very quickly.