I have a 1930 AWA Radiola C73 with surface rust on the chassis. On a radio of this age I prefer to preserve it and keep it as original as possible by preserving the original chassis paint rather than stripping and re coating the chassis. Is there a good rust treatment product that will treat the rust and prevent it from spreading while preserving the original gold chassis paint and painted valve markings?

Hi Sam,

A product that I have used for light rust is Inox MX3. I think I got my last can from Repco. I wouldn't recommend wholesale application without testing, but I have had good results with it stopping rust progressing and it is gentle on paint. It even does a good job of breaking up rust on things like screws and bolts if you give them a good soaking.

I don't think it would remove much rust though. For that I usually resort to the sand blaster and zinc primer. Not an option if you want to keep the original paint.

Regards, Frank.

P.S. Pictures please, I love all of the early AWA sets.

G'Day SamT

I was chasing some solutions myself.
I did some research and found a product made in Brisbane.
and it works, shock.!!, It's a gel, put it on thick and leave it for a few hours it will change from blue to black, then with a bit of water and a brush wash it off.
also it's not a toxic product, just avoid contact with it, as it has a blue dye in it.

Rusted solutions is the company.
rustedsolutions.com.au
I ended up buying the 1kg container.

I had a chassis from a Stromberg Carlson that had a lot of rust on the outside of the chassis, inside was like new.

It cleaned it up enough to make it presentable, a few areas required reapplications.
I had been using a wire brush on a dremell
Cheers

That could well be a product called commonly "Naval Jelly" more research needed. If it is the active agent is normally "Phosphoric Acid".

There is another which is actually a paste & things are purple; This sounds a bit more like it. Its active ingredient is Potassium Permanganate. It may have something else with it as Potassium Permanganate, depending on certain factors has something like nine oxidation states. One should be careful as to how you apply them as they can get inside IF cans, if left in the chassis.

I've used the stuff Flukeoneseventyfive mentions; it's not a passivating agent like Naval Jelly (phosphoric acid) but an actual rust remover - it lifts & dissolves rust, absorbing it into the gel & turning it black. Works fairly well, though you need to physically remove heavy rust first & oil/wax/seal the surface afterwards to prevent flash rusting (another clue that it's not a passivator).

The MSDS just says "Proprietary Blend of Organic Materials". I suspect it's EDTA or a similar chelating agent to bind the rust, in conjunction with something like sodium hydroxide to initially loosen the rust & provide the alkalinity needed to make EDTA soluble in the first place.

Organic could also include vinegar, & Oxalic Acid (Rhubarb leaves, unlikely as its a stomach poison) The pH is around that of Acetic Acid (Vinegar) so that puts paid to Alkali like Sodium Hydroxide.

For serious rust removal, nothing beats pure molasses heavily diluted with water. Slow heat accelerates the process -- which stinks to high heaven -- but it works. I have seen vintage motorcycle frames that were rusted beyond belief brought back with this process.

Ratio is around 1 molasses:20water the addition of a small amount of vinegar to tip the pH acidic I have also found a help.

I removed an about 40kg drill bit out of some yesterday: It will be used as a display.

One of the stupidest comments I have heard re doing this sort of thing is that it will leave "holes"???? The reality is that it is removing rust, the rust penetrates into the metal not just across it. The cleaning agent that chemically reacts with it follows it down. If you don't actually kill the rusting it will just continue.

One of the worst is steel where it will corrode in layers & exfoliate: That exfoliation and subsequent expansion can actually fracture a joint.