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post #2 of (permalink) Old 25th March 2007
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Hi there mate, I read that you have 'just' noticed the rust - is it just showing signs of its presence? The reason I ask is that your options will be dictated by the extent of the wheelarches (i.e. is the rust coming through from the inside of the panel, or is it surface rust?).

Also, is the rust on the inside edge or on the visible exterior?

You really need to assess this correctly to decide how to proceed - I'll try to cover all the bases, but you need to be aware, that rust is almost impossible to eradicate, it will be a weakness that will regularly need attention, but is always best dealt with as soon as possible.
  • If the rust is only on the surface and only on the inside of the wheelarch - sand down the rusty area (only) until you reach clean shiny metal - I would apply KURUST to the surface and allow it to work (this will go some way to remove any latent rust spots which would only re-occur). Then, I would apply some white Finnigan's Smoothrite (by brush) over the entire inside section of the wheelarch. I would probably do this for all remaining arches as a preventative measure. You can either leave it at that, or add a layer of underseal (again by brush) which can be freshened up from time to time.
  • If the rust is in the same place as above, but it has rusted through the metal, then the method is pretty much the same, but the rust has to be attacked from both sides. It is also highly unlikely that this repair will be robust, you are delaying the inevitable - a new section will at some point be needed.
  • If the rust is only appearing on the visible surface of the wing around the wheelarch and is only due to stonechipping (and the area is quite small) please read my feature on paint reconditioning in the 'how-to' section.
  • Again, if it has corroded right through, please refer to 2 sections above.
Spraying should really only be carried out as a last resort if the rust has been allowed to extend over a large area, but the principle is as follows;
  1. Always prepare & paint under cover
  2. Sand down the area to be painted (starting with coarse paper 80 grit on the rust, then gradually move to finer paper 240 grit, moving to 500 grit as you 'feather' the area surrounding. Apply KURUST.
  3. Mask off the area where you will be painting.
  4. Apply a couple of coats (the first quite light, the second a bit heavier) of primer and allow to dry.
  5. Remove the masking paper (except what is covering trim/tyre) and gently rub the primer and most importantly, the edges of the primer where it meets the original paint with extra fine paper - 800 grit. This is to ensure there is no 'edge' to the resultant repair.
  6. Shake the aerosol of white topcoat properly, and lightly spray over the repair area in sweeping motions (i.e. left to right). Begin with very light coats, becoming progressively heavier, but allow time to dry thoroughly between coats (even give a gentle rub with the extra fine paper to level out any surface impurities).
  7. Once you have given around 4-5 coats, leave the paint alone to harden (a couple of days, at least - unless you applying constant heat), then once it has become resilient, you can use a cutting compound (follow the instructions, but be gentle), followed by a polish to buff the fresh paint to a shine, and to blend in the repair with the remainder of the panel.
I hope this helps you - please feel free to ask away if you have any more questions from the above. Preparation and patience is the key to a robust and as professional-looking repair as is possible.

Post a picture of the area if you can.


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