[jrblasde]

Good morning, folks! I couldn’t find a thread specifically about rust removal, so let’s create one! We’ve already discussed, but I’ve got some substantial areas of rust on the chassis of my 46-480. My plan is to empty the chassis and then clean it up. I have two topics I would like to focus on—cadmium plating and rust removers.

First for the cadmium plating. I am aware that Philco plated their chassis with cadmium to inhibit rust. That said, did they still do this into the 1940’s? How do I know if my chassis is plated in cadmium? I know that it is dangerous to sand, scrape, etc. on cadmium, but I don’t know what my options are if this chassis has it.

Second, let’s talk about rust removal. Someone or other had mentioned their own success with Loctite naval jelly, so I purchased a jar of it. The instructions mention to rinse the metal after treatment. Do I need to rinse it in running water (such as in a sink) or do I submerge it in a bath of water? If we are not to use the sink, what should I do with the waste water?

[morzh]

I believe, an instruction simply said using water-saturated rag to wash the jelly off.

The jelly is applied to well-sanded area. Then after application and removal you look for specks of red (rust), and id it is still there, repeat the process.
The jelly, after the excess of it is washed off, will form some sort of compound with the residual rust/metal, that is stable and could be painted.

[jrblasde]

Thank you for the details. I didn’t see anything about a rag saturated with water on the packaging, but I saw that same explanation when I read online about it. Sounds simple enough. I also read that, for larger applications, baking soda can be sprinkled onto the metal after using the rag to neutralize any remaining phosphoric acid.

[Arran]

I've had good luck using a wad of paper towel, soaked in vinegar, on thick crusty rust that the usual rust removers won't touch, I fixed up the chassis in a Stewart Warner 6 volt battery set that way, cleaned it off, then applied phosphoric acid to the bare but pitted steel. I came up with that after trying muriatic acid on an even rustier chassis, it was nasty to work with and didn't really work all that great, I think I finally took a wire wheel on an angle grinder to get rid of the last of it, after I drilled out the sockets rivets (pushing them bellow the chassis), and removed the other chassis top parts that were in the way
 I don't know whether they really did use cadmium plating on Philco, or any other chassis, the older Philco chassis ook like they may have been zinc plated as they are a dull dark grey colour. Are there any home test kits for cadmium like there is for lead paint? I suspect that many chassis may have bee plated with tin, as that is what they used on tube shields, why use two different types of plating on the same chassis. Some companies, liek Stromberg Carlson used copper plate, and then switched to zinc chromate, which is a yellow colour. 
Happy Christmas
Happy New Year
Arran

[jrblasde]

I’m a big fan of vinegar as well. It works wonders to leave a rusty piece of metal soaking in vinegar for a few days. Regular 5% vinegar works fine, but I prefer the 6% “cleaning” vinegar when I can find it. After soaking, I’ll rinse the metal and then coat it in a paste of baking soda and leave it for a couple of hours. I’ve read that sodium bicarbonate will neutralize the acids present in any remaining rust. It also gives the metal a nice, clean look. After a couple of hours I will rinse off the baking soda and dry it thoroughly.

Having heard such good things about the naval jelly, I’m willing to give it a try this time.

[RodB]

You have to be selective with the rust removal chemicals and the metal. A while back I put a piece of rusted pot metal in a vinegar bath and the vinegar ate the whole thing.

[jrblasde]

Wow, really? I never thought vinegar could be so potent. Was the rust pretty severe to start with?

[morzh]

I am sure the pot metal wasn't quite rusty as much as itr was probably oxydized. Iron, which is what develops rust, was not a big part of PM, if any at all.