I am wondering if the product metal rescue works? The company shows videos where you just soak something rusted in it and like magic it comes out rust free.

How true is that? Are there any other cheaper/viable solutions?

Also, how do you determine how "deep" rust is? I know that surface rust is rather obvious but some times I have trouble gauging if something is rusted through all the way, pitted etc.?

At $25 a gallon I am rather hesitant to buy this product.

I think Metal Rescue may be similar to Evapo-Rust, which I use all the time. Dunk an item overnight and the rust is gone. Some things come out looking surprisingly close to new condition. Evapo-Rust is the same price range you mentioned -- about $23 per gallon from Advance Auto Parts.

For bigger items like frames, I use oxalic acid instead of Evapo-Rust due to the cost. A small tub of oxalic acid crystals sold as Savogran brand "wood bleach" sells for $8 at a local hardware store. Mixed with water, it'll fill a kids' wading pool. Dunk items overnight to remove rust, rinse well, and dry.

I haven't used Metal Rescue, but from the looks of things it's just calcium bicarb (Ca(HCO3)2). If you're patient, you can probably get equally good results with a molasses soak.

There are lots of chemical rust removers that work. The issue is that you have to be able to submerge the rusted area (often difficult on something large and unwieldy like a bicycle frame) and in many cases you have to neutralize/remove the chemical afterword (which can be tough for places like inside the frame tubing). Also note that you usually have to strip the part down to bare (rusted) steel. That's usually more work than the rust removal, and in some cases (media blasting) takes care of the rust for you. Also note that deeply rusted areas may need multiple treatments with manual removal of scale in between to expose the deeper oxide. Lastly, some chemicals will etch the metal in the process of removing the rust. That may or may not be a problem depending on the application.

Remember it doesn't really "rescue" (i.e. replace) metal, it merely removes the rust leaving behind a clean surface. Where the base metal has rusted away it is gone for good so if the part has rusted to the point of being weakened, the treatment won't make it any stronger.

Here are a few recent threads discussing it:
https://www.bikeforums.net/bicycle-me...scue-work.html

https://www.bikeforums.net/bicycle-me...scue-work.html

https://www.bikeforums.net/bicycle-me...er-method.html

https://www.bikeforums.net/bicycle-me...ms-spokes.html

And there are others.

Rust removers remove the rust chemically, but that's not in any way going to restore the steel lost to rust. What's gone is gone for good.

As for gauging the depth of rust, the most common method is to pick at with an ice pick in the same way as a dentist probes a cavity with a sharp dental pick. The only difference is the bike feels no pain.

I also use oxalic acid. I bought mine from a taxidermy supplier. One bag will last you years.

Not for the hardcore restoration people out there, but when I had my bicycle recycling program for kids and teenagers, we couldn't use chemicals so we removed surface rust with crumbled aluminum foil. It ultimately left sort of a "brushed" metal finish, but it was very effective. I also thought the brushed look was kind of cool.

For really bad rust, we'd soak the part in store-brand Cola for a few days. You'd be amazed at how much THAT stripped off!

Of course, as others have said, there's no replacing the protective qualities of the original coat of chrome

House paint is about the same price .