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Touching up an engine graze: proper enamel application?

Discussion in 'Bling and Appearance' at netrider.net.au started by Potatopi, Jan 6, 2013.

  1. Had a search around, all engine paint jobs seem to be whole resprays. I'm only looking for a touch-up.
    Previous owner had a low-speed laydown so I have a very light surface graze (about the size of a oval 5-10c piece) on the clutch housing cover.
    I want to touch this up with some black engine enamel so it's not a bright silver patch in the nice black paint of the engine.

    What's the proper procedure for doing this to avoid rust, problems, etc.

    I was thinking of getting a very very fine file and just smoothing off the graze (carefully of course).
    Then get it with a cleaner to ensure there's no dirt/grease/particles. (I have normal car wash concentrate and kero currently... and a clean tooth brush)
    Then getting some cleverly placed masking tape around the area to avoid spraying the paint everywhere.

    Is there anything else I should be looking at? This feels very much like a one-shot deal so I don't want to do something I could have easily avoided.
  2. cant see a problem matey.........rattlecanned an engine while it was still in the frame so....:rolleyes:
    personally though, I'd maybe take the clutch cover off, or mask up completely if you can... and paint the whole cover,.. you may well find the engine enamel is not quite the same colour black as the original and a10c piece job will stick out like a sore thumb..........better to blend it by doing the whole casing.
    Other than that, maybe use a lil' wet 'n dry paper on the graze rather than a file:eek: ferfuksake.... haha, then wipe it all down with a solvent like a grease & wax cleaner or some metho... dry, then paint:)

    • Like Like x 1
  3. As Rogues said, you can just rattle can it. Use VHT engine enamel, that should do the trick. I can't remember if you require etch primer with VHT branded engine enamel, but seeing as the metal surface isn't all that big, you might be okay.

    For a quick job, sand the whole cover lightly with 600 grit wet and dry until dull and the bare metal is smooth. Spray light coats of VHT evenly and let it dry for 30-60mins between coats. Once all sprayed let it dry overnight and it should cure as the engine heats up.

    For a more proper job, sand the whole cover back to bare metal, starting with abrasive wet and dry working towards 600 grit wet and dry, a coat of etch primer, sand lightly with 600 grit, a coat of normal primer, lightly sand with 800 grit, 2 light coats of colour and then a slightly heavier third coat, sand with 1000 grit and 2 coats of clear after that. That should give you a pretty decent finish, however as you can expect, it is very time consuming.

    It took me a good week and a half to finish the fairings of my race bike.
  4. If you want quick and easy
    black texta or Model paint.
    see which one matches the closest.
  5. .......:unsure: other problem being, touch-up paints or model paint will probably be too much of a gloss, otherwise one of them stick touch-ups from Supercheap would do the trick...
    I used the VHT that Phongus mentioned,.... sprayed it straight over a cleaned down engine.
    think you'll find doing a patch job you wont need the etch primer.. but if you rub it all back to bare metal YES!
  6. update: In typical fashion of me, I still haven't done it yet. I went out for a ride yesterday so I want to wash her again before I go ahead. Mixed with work (which, again I ride to) it's just been one of those things that gets plonked in the 'later' list.
    I will definitely post up the results when I have bit the bullet though. Stay tuned I suppose.
  7. When you get home from work, clean it, sand it down roughly with some 800grit, and clean again (if you're doing a quick job). Cover all areas with newspaper/plastic bags/tape you don't want paint on, spray 1 light coat (full coverage though), wait 20-30mins, spray another coat slightly thicker, but not so thick that it runs. Remove tape/newspaper/plastic bags and let it dry overnight. When you head to work, the engine heat will help cure the paint. Job can be done in say 2 hours or less if it's just the face of the cover.
  8. Alright, here we go.
    Gotta say first up, I'm rapped with the results - can't tell there was any scuff unless you get right up to it with the light.
    Unfortunately I didn't take any before photos except a quick one on my phone. Foolish, I know. I'll post it up anyway in a little bit, plus the after photo in the better day light.
    But if you can imagine the silver of a knife blade poking through the nice black powder coat, you're in the right direction.

    But I digress.
    Taking in the advice from you guys, I cleaned, sanded, cleaned, sanded some more and cleaned it again. Had a much more rounded silver spot now which I then taped up with plastic and sticky tape. I wasn't prepared to get it dead smooth because I feel that's taking too much off and I believe it takes too much out of the shape of the engine casing.

    Applied 2 light coats firstly (I sprayed a whole lot out onto some cardboard direction to ensure I had a clean, smooth stream). Then waited 10 mins til dry and applied another thicker coat. Then another til I had a nice smooth dark black cover.

    I then took all the tape/plastic off an noticed a rather distinct paint outline of where the protective taping finished. Not to worry, ripped a much larger hole in the plastic to uncover more of the general area (still covering everything else), stood back about another 15-20cm and sprayed a few 'dusting' coats of paint on the engine cover.

    Blended in beautifully I'm pleased to say. I was worried the paint would be quite shiny, and it was looking like it was going to be that way, until I took the step back and gave it the 'dusting' spray. That's the key I think. You don't want a thick layer, it's too wet and is very shiny.

    If I could do it again, I would change one part of my process. That is, not tape it up so tightly around the patch because it concentrated a rather thick layer of paint on the patch I was covering. You do need a thicker layer there obviously, but I would rip the larger hole in the protective plastic sooner so the paint could be evened a little easier. With how I did it, it was like I over-applied it and had to smudge out the sharp lines.

    1. Clean, sand, clean, sand, clean until it's smooth and the grazes are less obvious (you won't get it baby bottom smooth unless, I believe, you go a little too deep)
    2. Cover everything up.
    3. Cut focused hole exposing just the area to be patched.
    4. Spray the light coats to 'prime' it. Wait 10-20mins.
    5. Spray a little heavier coat (and I mean a little heavier) to give it a colour closer to the actual paint.
    6. Rip back the plastic to expose the general area. Step back. Spray the dusting coat in long, smooth strokes.
    7. Do as many dusting coats as necessary.
    8. Wait. Inspect handywork :)

    It's currently drying in the garage downstairs, I'll warm it up tomorrow to give it a baking. I have a good feeling it'll turn out really well.
  9. good for you mate... look forward to the piccies
    it shouldnt be too shiny once it dries........'tis only because its wet its giving you the angst.(y)
  10. Before: Sanded as much as I was comfortable with and cleaned. This was a phone photo in the garage with no real proper light.

    From about 1m away:

    Closer. Still can't really tell.

    Closer and underneath, only angle you can actually see the touch-up:

    As I said, really happy with how it turned out, thanks for the tips, pretty sure I would've stuffed it up somehow if I didn't stop, think about it and ask for some pointers / an alternate perspective.