Rust Removal - Naval Jelly?

[kalee20]

Coca cola also contains phosphoric acid. I've not tried it as a rust remover, but I would not be surprised if it was slow but effective.

And yes, molasses also works, similarly slow. Get the crude raw stuff (agricultural feed suppliers) rather than the partially refined supermarket black treacle. Down side is it makes everything sticky - but then you can just lick your fingers...

[Bazz4CQJ]

The pictures of the set treated with Evaporust certainly look good. Looking at the SDS for that product, it is 83% water, 16% 'Proprietary non-hazardous chelating agent' and 1% detergent. It says that if you drink it 'it may cause discomfort', which limits the options, as most chemicals (e.g. oxalic acid), will do worse than that. Could that chelating agent be nothing more than citric acid?

B

[Ti Pwun]

Originally Posted by Bazz4CQJ

...Could that chelating agent be nothing more than citric acid?

B

Something to experiment with, perhaps? I do suspect the ingredients are all readily available for not much money so it might be worth the effort.

[Bazz4CQJ]

Originally Posted by Ti Pwun

Something to experiment with, perhaps? I do suspect the ingredients are all readily available for not much money so it might be worth the effort.

My impression regarding everything supplied by the Frost company (as per Evaporust) is that it is good, imported from the USA, and a tad expensive. I think it is my "Yorkshire gene" that twitches adversly in such circumstances . Again, searching Google will find lots of hits re citric acid cleaning, and it's available in Wilko (and elsewhere) very cheaply.

B

[Craig Sawyers]

Originally Posted by kalee20

Coca cola also contains phosphoric acid. I've not tried it as a rust remover, but I would not be surprised if it was slow but effective.

The very original recipe used to have cocaine in it - from coca leaves (hence the coca of coca cola), and it did not have phosphoric acid.

However the current recipe it is still highly addictive because of high-fructose corn syrup in it - 38g of it in a can. Addictive sugar and tooth rotting phosphoric acid - what could possibly go wrong with that?

On-topic, the presence of phosphoric acid ought to have some positive effect on rust.

Craig

[ex seismic]

I use Exit Rust on car bits, seems to work well. Wash it off paint work promptly or face some effort polishing the stains out. The supplier can be found by a quick Google.

Gordon

[suebutcher]

Phosphoric acid rust removers will also remove zinc plating, so you must take care when removing spots of rust from a plated chassis.

[John G8MWF]

Hello Sue,

That IS the question I am trying to get an answer to - are these chassis coated or plated with something?
And if they are then presumably they will need protection after the rust is remove?

[suebutcher]

If it was mine, I'd use a multimeter to see if the surface was metal, or varnished or painted. If the surface conducts, it's either bare steel, or plated with zinc, nickel, tin, brass or copper. In my experience, tin isn't affected by phosphoric acid. Zinc is dissolved. I think nickel is safe. Brass is discoloured as the zinc in it is attacked. Copper, I'm not sure, it might be safe.

[John G8MWF]

I have enclosed a picture of typical rust for this series of Radio. The file is called Cossor rust and I hope that this picture will give you a good idea of what I am up against!

So, I am not prepared to take the radio fully apart for this treatment as I would really like to preserve what workmanship is still left from 1949. Painting it would also change the appearance and probably mean a total rebuild.

The questions that I cannot find an answer to at the moment - did they treat the metal chassis during manufacturing or was it left bare? When you look at the underside of the chassis it 'appears' to be bare!

[Craig Sawyers]

I'd take the valves out, and masking tape over the sockets, the mains transformer, the tuning cap and (after wrapping in tissue paper) that vertical coil.

Then go at it with a small wire brush and wire pencil, and/or Scotchbrite. It just looks like surface rust to me. Then wipe over with a rag with white spirit until the rust colour stops coming off. Repeat as necessary until the chassis looks clean. Or a lot cleaner at least.

Off with the masking tape and back in with the valves.

[suebutcher]

John, that looks like zinc plating; zinc weathers to a matt light grey. So avoid phosphoric acid. I'd do what Craig suggests. If you use a wire brush, make sure it's a fine one and don't scrub hard or the metal will be visibly scratched. Once you've finished, rub a light coat of WD40 or similar over the cleaned area to slow further corrosion. Or you could try a thin coat of zinc paint, perhaps mixed with some model paint to match it with the surrounding plating.

[stevehertz]

Originally Posted by suebutcher

John, that looks like zinc plating; zinc weathers to a matt light grey. So avoid phosphoric acid. I'd do what Craig suggests. If you use a wire brush, make sure it's a fine one and don't scrub hard or the metal will be visibly scratched. Once you've finished, rub a light coat of WD40 or similar over the cleaned area to slow further corrosion. Or you could try a thin coat of zinc paint, perhaps mixed with some model paint to match it with the surrounding plating.

Indeed, what I said in post 8!

[TrevorG3VLF]

I believe that cadmium plating was used at some time. Very nasty, scrubbing this would be dangerous.

[robin coleman]

A lot of the Quad chassis were cadmium plated. I have used Jenolite for years now, but I have used a new product for rust removal from the WD40 range. I have also used citric acid mixed with salt on a few rusty screening cans.

Regards, Robin.