The unsightly reddish brown stain on your brand name tools is a sign that it needs some decent rust treatment. So to remove it from metal, you have two options: you can either use a removal product or a converter.
Although these treatment products have the same goal – and that is to remove rust from metal – they achieve this in totally different ways. So comparing converters with removal products is much like comparing apples and oranges. They may be in the same class of products, but they both work in their own special way.
As the name implies, converters work to remove rust from metal objects by converting the iron oxide (i.e., “rust”) into a harmless and inert compound. Curiously enough, the Rust Paint resulting inert compound even provides some form of protection from corrosion.
The key ingredient in most converters is phosphoric acid. This acts by binding with the iron oxide to form a new compound − iron phosphate. You’ll know when the rust has been totally converted into iron phosphate when its reddish brown tinge turns black.
The advantage of phosphoric acid is that it leaves a protective coat of iron phosphate. This inert and harmless compound prevents rusting. Iron phosphate isn’t durable and you will need to use a product specific to surface protection.
The common practice is to add a coat of anti-rust paint to the treated metal surface. This ensures that no further corrosion will take place as long as the topcoat is intact.
The main advantage of using converters as a treatment method is it saves you from the tedious work of scraping every bit of the red stuff from the affected metal surface. The traditional approach of removal is some elbow grease and a considerable amount of patience.
In using a converter, all you have to do is to scrape off any loose red flakes and then apply the converter paint over the corroded area. Then wait for the converter product to do its job (usually overnight to 24 hours, depending on the extent of the corrosion).
Once the corrosion turns completely from reddish brown to black then you know that the converter has already neutralized the iron oxide into an inert and harmless compound. All you have to do now is to add a layer or two of topcoat and you’re done for the day.
Unlike converters, removal products require some serious elbow grease to remove rusting stains from metal surfaces. This is the traditional method. This means that you have to remove every bit from the metal surface using a removal product to help you get the job done.
The purpose of the remover is to help you speed things up by using a very powerful acid to remove any iron oxide (a.k.a. “rust”) still clinging to the metal surface. No chemical transformation takes place as in the case of converters.
To remove rust from metal, you start by applying the remover to the corroded area. The acid then reacts with the iron oxide particles causing it to separate from the metal surface. Most removers use oxalic acid as its active ingredient. Unfortunately, oxalic acid is a highly toxic chemical and should be used with extreme caution.