Chip Repair Problem!

[AustrianOak82]

Hey guys. Having a problem with a touch-up job and wanted to see if anyone had input. I was doing chip repair on a 2010 Toyota 4Runner. I picked up some TU from O'Reilly in Salsa Red and prepped the chips for painting. Here are the steps I took:

1. Applied the paint using a fine detail brush
2. Dried chips using a heat gun on low from about 2 feet away. I did this for 2-3 minutes and checked about every 30 seconds to make sure the paint surface wasn't hot.
3. I allowed the chips to dry another 15-30 minutes and got ready for wet sanding.
4. I wet sanded the chips using Meguiar's Unigrit 2500 until level.
5. I then repeated the above steps for the 2nd coat.

When I started sanding the 2nd coat, I noticed the TU was turning very dark gray, almost black. The paint was not tacky when I started sanding and had a hard feel to it. I went ahead and applied another coat over the top and went a little light and smoother this time around. I sanded lightly with 3000 and got the same result. In the end, the photo shows what I was left with. I am getting the car back in about a week for round two and need to figure out what happened here. I posted on AG and some guy suggested maybe during the drying process, the flakes had settled/floated so when I began to sand, I was only blending in the darker flakes with the red tone underneath. I figured I would post on here as well and see if anyone had this issue before and had any feedback. Thanks!

 

[Accumulator]

AustrianOak82- Welcome to Autopia!

Some sorta-random thoughts about your situation follow:

-I wouldn't use the heat gun to speed up the drying
-I wouldn't wetsand between coats of TU paint
-I'd do more (and thinner) coats of TU paint
-I'd be shake shake shaking a metallic TU paint, like...all the time
-I'd quit if/when I noticed the color getting weird
-I'd let the TU paint dry/cure for a while before trying to wetsand it
-I'd verify that the TU paint you're using (is it single stage?) will respond well to wetsanding (some paints don't)

I dunno if any of the above will be helpful, but that's what came to mind.

 

[edb]

I thought i read a couple of posts on touch-ups a few months ago where the original poster said he would put the touch up paint in then wait a month for the paint to fully cure before wetsanding etc. I believe one of the reasons was to make sure the touch up paint doesn't come out while wet sanding and compounding. His results looked excellent. I will see if i can't dig up a link.

 

[Accumulator]

edb- I'm one of those guys who'll wait a *long* time...dunno if it's necessary but that's generally what I do when using conventional touchup paint. With DRColorChip I don't wait nearly as long.

 

[ShaneB]

I wouldn't sand the paint at all either. Also sanding with anything higher than 600 grit will cause adhesion issues as you don't give the fresh paint anything to bite on to.

There is a difference between dried paint and cured paint. Paint that is dry yet hasn't fully cured, can be layered without any additional steps. Cured paint (given a long time to dry, from days to weeks) will need to be sanded to allow the fresh paint to adhere

 

[AustrianOak82]

I will probably go ahead and pick up a different brand of TU paint. I will sand these down smooth and apply a thin layer over the top and let it dry for a week or two. The chips are pretty much totally filled in, so we will see what happens.

 

[Accumulator]

I will probably go ahead and pick up a different brand of TU paint. I will sand these down smooth ...

I myself probably wouldn't do that. If I needed to undo any of the existing touchup I'd do it with something like Langka's Blob Eliminator. I worry about all that sanding affecting the OE paint for one thing...