Touch-up paint quandary

I'd like to fix some minor scratches on my car with a dealer supplied touch-up paint set, but this one came with only pictoral instructions without any narrative. It's mostly self-explanatory though, with some exception, at least for me. I thought maybe some of you can help me out with it. I am including a scan of the pictorial here:

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My quandaries start with pic. 1 and 10, which I interpret as "no shaking" instructions. I find this odd, because I would expect just the opposite. Pic 4 shows applying the base coat and pics 6 through 8 perhaps repetition of the same. Then after that is dry, pic 10 shows the application of clear coat. Am I getting it right?

Thanks for any help with this.

Reply to
Cameo
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My guess is:

  1. Do NOT shake the bottle of base coat. That would add bubbles of air. It is a thick paint. You don't want bubbles in the paint job. 2. Apply base coat between temperatures of +5 to +35 (Celsius). 3. Clean affected spot (no mention what to use - guessing isopropyl alcohol). 4. Apply base coat. 5. Wait 10 minutes to let dry. 6. Apply water to tip. 7. Press tip onto dried base coat. Rub around to absord excess paint. 8. Rinse off tip of absorbed base coat. 9. Wait 10 minutes to dry.
  2. Do NOT shake bottle of clear coat. That would add bubbles of air. It is a thick paint. You don't want bubbles in the paint job.
  3. Apply clear coat between temperatures of +5 to +35 (Celsius).
  4. Dab on some clear coat.
  5. Wait 20 minutes to let dry.
  6. OK, you're done with the paint job.
  7. Wait 48 hours to let paint harden.
  8. Use the polishing compound to blend. Buff off polishing compound.

Touch-up paint is a lot thicker than what you get in spray cans. That is to prevent the paint from sagging since you are brushing it on instead of apply a multiple to thin spray painted layers. While you can shake water-based paints because they're thinner to glide onto the surface, the same would happen if you shake enamel paint which adds bubbles, and you'll end up painting bubbles onto the surface. If enamel paint has separated its oil from the pigment, you fold the oil into the paint using a stirrer stick. You don't shake the can or whip up the enamel paint. Alternatively you can use a mixer paddle attached to a drill at low speed. The end is dipped into the paint, and then it spins. Since the paddles are under the surface, there is no air to mix into the paint. You're just moving the settled pigment and oil together. For a small cap-size quantity, you can remove the brush and head shell from an electric toothbrush leaving behind just the vibrating rod to stir the paint. You want to fold the oil into the pigment. You don't want to fold in any air. Depends on what surface effect you want. If you want a glass surface, keep out the air. If you're using a paint roller, well, that adds texture, so air isn't a problem. I doubt you want any paint on your car to look like it was applied with a roller.

You never want to paint over rust even if you don't see any. I would use 1800, or higher (3000), grit sandpaper to prep the paint chipped spot. Then apply rust converter (aka rust reformer which is water soluable tannic acid with organic polymer) paint. The tannic acid converts the rust (iron oxide) to stable (inert) iron tannate, and the polymer acts as a primer layer. The idea is not to polish down to shiny metal since the intention is to convert unstable dusty or flaking rust into smooth stable iron tannate with a primer. You just want to get rid of any dusty or flaking rust, and to make for a smooth surface to have a smooth paint job. If you polish down to bare metal, there's no rust to convert, but you'll need to use a primer before the base coat. Rust convert doesn't work on aluminum, galvanized metal, stainless steel, or copper. It needs to be iron or steel (but not stainless). Even if there is no rust (that you can see), rust converter is still a good primer for the base coat. Takes 2 to 4 coats of converter to build up a decently think primer layer. The thinner the converter solution, the more coats are needed.

Most seem to come as a spray can (to cover large taped-off areas), so I'd spray into the cap to puddle it up to dab into the paint chipped spot with an ear swab (while spinning the tip to keep cotton filaments from coming lose and stuck in the paint, or use a small tip paint brush and wipe excess off with rag and reapply with a 2nd coat). Wait however long the converter paint says to let harden (1 hour between coats, 48 hours to harden). Use the high grit sandpaper to prep the paint for the base coat paint. Then I'd apply their base coat. The rust converter paint is sufficient. Adding the base coat and clear coat is for looks (to hide the paint chips by masking with a similar color paint and similar depth of sheen).

Drying time depends on temperature and humidity (and, of course, some airflow over the paint). The recommendations are you don't apply the next paint layer until the last coat has dried to the touch. However, if you touch the paint to test and it's still tacky, then you just left a fingerprint in the not-yet-dried paint. It's your call as to when the paint has completely dried and ready for another coat. Also, when applying another coat, it "wets" the prior coat. I've run into the problem that I thought the paint was dry but was impatient in waiting. Yeah, it seemed dry, but the next coat sagged.

Reply to
VanguardLH

Thanks for the info. It's been a while since I used factory touch-up paint and at that time one had to shake the small paint container till the metal ball inside was freely moving in the paint fluid.

I am also suprised that I'd have to apply water to the tip as I would have thought lacquer thinner would have to be used.

Reply to
Cameo

I read that automobile manufacturers all switched to water based paints in the mid '80's because of VOC's.

I knew the biggest source of pollution from the auto plants came from the painting part of the plant.

Would be interesting to tour a plant today. I was in an R&D group working on auto-body resins and toughest problem was getting a plastic to survive the paint process, specifically the high temperature bake ovens. In the Pontiac Fiero plant they had to paint the body parts on supports before putting on the car.

Reply to
Frank

Spray paint (cans or air tool) are much thinner so, yeah, they need to be shaken or stirred to get the pigment solids back into an emulsion. You kit isn't a spray can product wherein a stainless steel ball is used to get the pigments back into an emulsion. I usually used the applicator style touch-up paint once (well, over a couple days to do multiple coats), and then tossed the rest. If I need to touch up again in a year, or more, I get new stuff. I can do lots of offroading without any paint dings, but when they spread tar and coat with stone chips is when the nicks start showing up (and I've even had those sharp chipped stones wedge into my tires to cause punctures).

From the drying time proposed, looks like the touch-up paint is water based. Oil based would take longer (like 6 times longer) not just to get tacky but to thoroughly dry before the next coat. The base coat can be water based (as are many other car mfr paints), and why you see a dab-off and cleanup steps using water. The clear coat is a lacquer, and why there is no cleanup step.

I haven't used a 2-part touch-up paint product in a long time. It's just been a single application product that has a polymeric acrylic resin (in beads of methlpropyl ketones) and solvent (acetone, xylene, or naptha), and perhaps some silica to adjust the sheen or matt-ness, so dry time is quicker, and it's easier with 1 application without intervening drying times). No separate clear coat is needed. For paint chips, that is sufficient. For larger areas, you might want a clear coat if the rest of the paint has one, so the depth of sheen is similar. However, most touch-up paint gets dabbed into the chipped spot leaving a ridge behind unless the user builds up using multiple coats (to get reversed, so the new paint feels like a slight ridge higher than the rest of the paint), and then buffs out the paint so it is even with the rest of the paint. That's not how most touch-up paint is used. Most users don't even use a rust converter paint resulting in a botched paint job that flakes off due to remnant rust underneath. Considering how far away are eyes from the surface of your car, and others don't often run their hands over your car (why are they stroking your car?), the ridges are often imperceptible. Well, until you walk around your car to see the ridges because you know they're there.

Also, you should use a wax remover before applying paint. You can, for example, use Ivory soap. Do NOT use Dawn. Many car soaps contain wax.

Reply to
VanguardLH

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