Thickening touch up paint

[KSMike]

I had my local body shop mix up small bottles of touch up paint for use in an air brush, but it would be nice to also be able to use that same supply of paint to fill deep scratches. The problem is that the paint is so thin it takes many, many layers (using a tiny detail artist's brush) to fill a deep scratch. Does anyone know a way to thicken paint that has been reduced?

Next choice would be to fill most of the scratch with spot putty, but I haven't worked with that enough to know what to expect.

Mike

[Setec Astronomy]

Usually people want to thin the paint down because it's too thick and blobby. Honestly, several thin layers built up is the best way to fill with touch up paint...which is probably why I hate doing touch up...(well, actually because it never comes out as good as I would like).

[KSMike]

Yeah I was just hoping there might me some additive or filler that could be used to thicken up a small quantity of it to save me some time. Oh well, thanks.

[Setec Astronomy]

Leave it open for an hour or so that should thicken it up.

[BillE]

Leave it open for an hour or so that should thicken it up.

:iagree:

Just put some in a small container (like a thimble) and let it evap some. Shouldn't take very long.

Bill

[Don M]

My grandma always used flour to thicken things up ... oh, wait, that's for cooking, never mind.

[Setec Astronomy]

I'm envisioning the next thread "what do I use to thin down my touchup paint?"

[99monguse]

I have seen videos of people using some Bondo puddy to fill the scratch and then apply touch up paint, then wet sand level

[2black1s]

I disagree with any method that uses spot putty (or other filler) to fill in scratches - here's why: If you fill the scratch with a filler prior to the paint the your finished repair will be higher than the surrounding area. Even if the filler shrinks prior to top-coating it will typically "dirty" up the edge of the repair and then you end up with a ring around the edge of the repair if you try to sand it flat.

Instead I like to use the color simply for that - color. Then finish filling the defect with clear urethane which can be sanded and polished flat for a nearly undetectable repair.

Here's the process I use...

Paint Chip Touch-Up

I'm an old body shop and paint guy. Don't do it any more but did a lot of custom cars and bikes back in the 1970 – 2000 time frame.

The best process I've found for touching up chips on BC/CC finishes (short of repainting the entire panel) is this...

1) Using the edge of a razor blade or Exacto knife, test the margins of the chip for adhesion and carefully chip/trim away any paint that is not firmly adhered to the substrate.
2) Clean the damaged area using a swap and solvent. Enamel reducer or alcohol is my solvent of choice as it will not damage the existing painted surface.
3) Using a fine tip artist’s brush, dab the chip with the appropriate color. Do not try to make the color coat flush to the existing painted surface - you need room for the clear-coat. Minimize any application of paint outside the margin of the chip being repaired. If you do exceed the margin, clean away the excess as described below in step 6). As with most paint applications, multiple thin coats/layers are preferred over a single heavy coat.
4) Allow the color coat to dry thoroughly. It will shrink a little as it dries and if you did step 3 correctly the touched-up color surface will be lower than the existing paint surface.
5) Carefully clean away any remaining excess color that may have exceeded the margin of the chip. If you're really careful a new and sharp single edge razor blade works well. Very fine (i.e., 1500G) wet-or-dry sandpaper is another option.
6) Again, using your artists brush, apply the clear coat in thin coats until the chip is filled flush or slightly higher than the existing paint surface. As in step 3), minimize exceeding the margins of the chip. Where you do exceed the margins or your paint build is too high, squeegee or slice away the excess using the edge of a credit card, a single edge razor blade, or a swab dampened with an appropriate solvent. Any smeared paint resulting from squeegeeing can also be removed with a swab dampened with an appropriate solvent, or with a light sanding once dried. Slightly exceeding the margins with the final coat is acceptable, and even desirable, as long as it’s a very thin coat. Allow to dry thoroughly between coats and overnight or longer for the final coat.
7) Wet sand the repaired area with 1500G wet-or-dry paper.
8) Polish the repaired area.

It takes some time and patience, but done correctly, this process will yield a virtually undetectable repair on solid colors such as black, white, red, etc. Other colors such as metallics, pearls, etc., are more difficult because it's very difficult to match the lay of the metallic when touching-up with a brush.

All of the materials needed including the paint can be obtained at most automotive paint supply stores.

Hope this might help some of you in the future.

As for the original question about thickening the touch-up paint I agree with the previous posts - just pour out a small amount and let it air dry for a while.

[Setec Astronomy]

I disagree with any method that uses spot putty (or other filler) to fill in scratches - here's why: If you fill the scratch with a filler prior to the paint the your finished repair will be higher than the surrounding area. Even if the filler shrinks prior to top-coating it will typically "dirty" up the edge of the repair and the you end up with a ring around the edge of the repair if you try to sand it flat.

I agree--I don't understand the concept of using putty for a scratch, and I was, er...scratching my head when that guy Larry had a video doing that. Of course a chip or scratch combined with a ding might be a different story.

Oh, and that's a great method you posted, that should help a lot of people. The only thing I'm confused about is the urethane clear--isn't touchup (other than rattle can 2K clear) always lacquer?

[2black1s]

I agree--I don't understand the concept of using putty for a scratch, and I was, er...scratching my head when that guy Larry had a video doing that. Of course a chip or scratch combined with a ding might be a different story.

Oh, and that's a great method you posted, that should help a lot of people. The only thing I'm confused about is the urethane clear--isn't touchup (other than rattle can 2K clear) always lacquer?

I don't use "touch up paint" per say. I use some base coat (color) and follow that with the clear urethane. Like I said, I'm an old paint guy and I still dabble with it from time-to-time so I have plenty of materials laying around.

I hate lacquer (and refuse to use it) for touching up today's finishes. It's faster and if time is a concern it has that advantage, but the finished repair will never look as good as it should. Of course, that's only my opinion and my experience. Others may argue that point.

[Setec Astronomy]

I hate lacquer (and refuse to use it) for touching up today's finishes. It's faster and if time is a concern it has that advantage, but the finished repair will never look as good as it should. Of course, that's only my opinion and my experience. Others may argue that point.

Not arguing at all, it's just that most of us are limited to using dealer or (chain) auto store touchup, or Dr. Colorchip or one of the touch up paint websites, and as far as I know that's all lacquer.

Are you saying that if I go to an autobody store (if I can find one anymore) that I can get one-part urethane clear? Or are you saying you are mixing up real 2K clear for this?

[KSMike]

Here's the process I use...



THANK YOU so much for sharing your knowledge on this point. It never even occurred to me to fill with clear - I've been so obsessed with getting the damage flush before the clear, I never even thought of it.

On the point of letting a bit of paint air dry to thicken it - I considered that, but figured the loss of solvent would harm the paint's ability to adhere, or level, or something... I'm over-thinking this.


I'm envisioning the next thread "what do I use to thin down my touchup paint?"

Welp, not from me at least. ;)

[2black1s]

Not arguing at all, it's just that most of us are limited to using dealer or (chain) auto store touchup, or Dr. Colorchip or one of the touch up paint websites, and as far as I know that's all lacquer.

Are you saying that if I go to an autobody store (if I can find one anymore) that I can get one-part urethane clear? Or are you saying you are mixing up real 2K clear for this?

I'm not aware of any single component clear urethanes and if there are any I'm certain that they are not as good as the real thing.

I do mix my 2-part urethane for these repairs using an eye dropper or measuring spoons. You don't need very much.

All this stuff is available at auto paint supply stores or even some body shops.

[BillE]

Interesting thread gentlemen.

Thanx for the insights...

Bill