Fe-123 is an easy-to-use rust converter that prepares the surface ready for coating with a suitable paint or wax for further long lasting protection. Below are instructions that will enable you to get the best results from Fe-123.

Shake the bottle

When you receive your bottle of Fe-123 it will have settled due to the zinc content in the binder. Just give it a good shake every time you want to use it to mix the contents and achieve the correct consistency.

Surface preparation

Ideally, treat the surface with suitable preparation products such as a salt remover and de-greaser and rinse before removing loose rust with a wire brush or power tool. This is because you want to avoid pushing dirt, salt and grease into the metal while wire brushing, as these can prevent the Fe-123 from fully reacting with the corrosion.

Once you have removed the loose dirt and rust and are down to a solid, stable surface, you are ready to apply the Fe-123. IMPORTANT: DO NOT degrease the prepared area with a white spirit, diesel or paraffin as the oil in these products may prevent the Fe-123 from reacting.


Pour a small amount of Fe-123 into a separate container to avoid contaminating the product in your bottle. Apply Fe-123 sparingly by brush directly to surface rust, working it into the metal. Allow the product around 15-60 minutes to convert (time taken will depend on the temperature – may take longer in colder conditions).

The Fe-1213 will initially turn purple on contact with corrosion, and then once converted the metal will turn to a hard, black stabilised surface. If this doesn’t happen there may not have been enough oxides present for the conversion to happen. Alternatively, it may have been applied in cold conditions.

If any Fe-123 gets onto paintwork or bright (non-corroded) metalwork, allow it to dry and remove by gently rubbing over with a Scotch-Brite pad or fine grade sandpaper (e.g. 320 or finer).

You DO NOT need to neutralise the Fe-123 with water, unlike some rust converters.

Issues that can stop the converter from reacting with the rust

  • There was no rust to convert. Remember that Fe-123 can only work where there is rust to convert. When applied to non-corroded metal, no reaction can take place.
  • Conditions were too cold. As mentioned above, cold conditions can affect performance. As a guide, 20c is an optimum temperature, with 10c the minimum. If working in a cold workshop, we suggest heating the ambient temperature around the area you are working on prior to and after application.
  • Two coats were applied. Two coats is not a good idea unless it’s obvious that you have missed a section. A second coat applied over a reacted coat will just turn a sort of toffee colour where the resin dries with nothing to react to.
  • The converter was applied to a painted surface. Fe-123 is also likely to turn a toffee colour when applied over paint. There is no need to apply converter to a painted surface. If there are small rust spots on the surface of the paint, carefully apply Fe-123 only to those areas (‘spot priming’).
  • Too much converter was used. Use only enough Fe-123 as required to react with the surface of the steel. The Fe-123 is to be used as a surface treatment, not a thick coating.

Painting/waxing over Fe-123

A primer, primer-finisher or wax product should be applied over Fe-123. You can apply any of Rustbuster’s primers (apart from zinc rich coatings – see below) or waxes over an Fe-123 prepared surface. The converted surface should be ready for coating after two hours, although longer may be needed in cold conditions.

We DO NOT recommend that zinc rich coatings are applied over the Fe-123 as the reaction and latex barrier have shut down the electrical connection with the steel that the zinc particles require.


Like all water-based products, you shouldn’t allow Fe-123 to freeze. We recommend storing it at around 20c (room temperature).



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