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Small rust patches

Discussion in ''How To' & 'Handy Hints'' started by The 4 of bus, Dec 29, 2018.

  1. The 4 of bus

    The 4 of bus Member

    Hi all,

    Thanks in advance for your help. Just started peeling back carpets and things in our kombi. Is it worth standing (wire brushing) back areas like this and then putting on penetrol and a quick repaint? Or what would you do in this situation?

    Attached Files:

  2. Barry

    Barry Well-Known Member

    Abbotsford NSW
    Yep - that’s what I would do.
    Just make sure after rain the water doesn’t pool there
  3. cbus

    cbus Well-Known Member

    sunshine coast
    2 negatives to keep in mind when choosing treatment process.

    Mechanised wire brushing tends to burnish the rust and prevent penetration of following treatments.
    Hand brushing not so much.

    Penetrol is good in that it penetrates and hardens but is an alkyd similar to oil paints so cannot be over coated with a paint containing GP or lacquer thinners unless a tie coat used.
    Enamel is slow drying so not so suitable under mat.
    Also to seal, 2 coats of penetrol needed.

    My pick for temp fix would be couple coats penetrol or lanolin.
    Lanolin doesn't dry but very effective in rust control.
    Easily removed if you want to paint properly later.

    Preferred option would be degrease n rinse total area.
    A strip it disk on grinder over all rusted surface and sand rest with 180 grit dry to prep surface for paint.
    Wax n grease remover to clean, wiping dry to lift any contamination.

    Treat metal with phosphoric acid. Wipe off with damp cloth then dry with metho on clean rag.

    Prime metal with a 2 pac epoxy primer.
    This gives a waterproof finish.
    Can be over coated with any type of paint but observe instructions.
    In particular that epoxy requires sanding or a fresh coat before overcoating if left more than a week. ie longer than " recoat" period.

    https://www.smithandarrow.com.au/product/poly-clean-strip-discs-wheels-paint-rust-removal/clean-strip-discs-4-5-115mm-paint-removal-angle-grinder/?attribute_box-size=Box 2&attribute_grit=Medium&adTribesID=d73d065531f1cd451fa47150c94348ad|adtribes|10242&utm_source=Google Shopping&utm_campaign=Trial 4&utm_medium=cpc&utm_term=10242&gclid=Cj0KCQiA05zhBRCMARIsACKDWjf0x
    Blue tends ti hold together better than black.
    Might be a brand thing.

    Feronite is a tannic acid type converter. Works well on rust but not bare metal. For this application , being ground surface, I would use phosphoric acid type.

    https://www.jotun.com/Datasheets/Download?url=/TDS/TDS__618__Penguard Special__Euk__GB.pdf
    Epoxy primer. Wattyl and others do same.
    Zinc not nessary over the phos acid treatment. A high build version is easier sanding.
    Available from many multi purpose paint stores or boat chandlery.
    2 coats is a permenant fix .

    In all things....follow instructions and they work.

    Ensure acid wiped with damp rag or it will inhibit epoxy cure.
    Last edited: Dec 30, 2018
    rstucke, Wayne murray and Barry like this.
  4. The 4 of bus

    The 4 of bus Member

    Thanks for such a detailed reply Cbus. Forgive my ignorance as we have never done this before but if went the full hog like you have suggested, would it still be classed as a temp fix? Probably looking at stripping the car back in a couple of years for a more extensive rust repairs and a repaint but obviously want to try and stop the little bits from getting worse.

    In terms of painting it with the 2pac, I've always thought that you have to do that as a whole car type thing or can you get that type of paint in smaller quantities that we can do ourselves?

  5. 76kampa

    76kampa Active Member

    Put some kind of kill rust on it before painting.
  6. cbus

    cbus Well-Known Member

    sunshine coast
    The suggested fix would only need decreasing with wax and grease remover, sanding with 180grit dry ti give a smooth clean surface, and a fresh coat of epoxy or other 2 pac primer to ensure adhesion of following coats.

    2 pac colour can be bought from auto or many other paint shops in any quantity from 250ml up.
    Hardner in cans min 500ml probably.

    You can do a panel at a time in 2 pac if desired.
    Assessing the type of paint already in kombi is important.
    Factory baked acrylic enamel is fine for any recoating type.
    Over acrylic lacquer repairs ok as long as they are sound. Usualy you would sand down to repair in any sus spots to check.
    Over enamel can be a problem. Best to remove it plus its primer to ensure no reaction.
    Although it is possible to seal enamel with sealers or tie coats then proceed as normal.

    You must want observe ventilation and protective gear warnings with 2 pac as it contains isocyanates.
    Also cannot be sprayed unless In a proper booth.
    If in the country you would be fine but it shouldn't drift to dwellings.

    Its pretty much the same as spraying enamel but dries faster and much harder.
    With a bit if skill theresvlittle or no compounding as is required for lacquer.

    Do a panel at a time is an easy way to control finish if learning.

    It drifts and sticks so good masking is essential.

    Use measuring cups to mix to ensure accuracy.

    Don't do a full bare metal repaint unless absoloutly necessary
  7. cbus

    cbus Well-Known Member

    sunshine coast
    Even if you intended to use lacquer later , the epoxy is a good first primer.
    It is fully waterproof if a good build (2 coats minimum to ensure no thin areas) and excellent adhesion to metal and other coatings.
    Acrylic lacquer primer is not a water barrier.

    To convert to lacquer system .
    Just let epoxy get a good cure
    ( couple days) then sand and apply an acrylic primer.
    Continue with acrylic as normal.

    This is handy in particular if doing a full respray over a period it time and some parts bare metal.
    Ensures no rust develops under the acrylic primer in humid conditions.

    Buying 4 litre kits of industrial/marine epoxy primer is cheaper and top quality.
    Just harder to sand than urethane automotive high builds.
    But still workable. Not for fine, full panel , blocking unless you like hard work.
    $100vs $250 ish.
    Last edited: Dec 30, 2018
  8. The 4 of bus

    The 4 of bus Member

    Thanks for all your help. Here is a before and after for you, followed all your steps cbus, much appreciated.

    Attached Files:

    deeksy62, cbus, Wayne murray and 3 others like this.

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