Newbie Tri Coat Question(s)

[Philip Long]

Philip Long

June 20, 2012 at 5:41 pm #37344

Hi, all!

I have an opportunity to do a tri coat soon. Long Beach Blue Pearl in DuPont Chroma Base system. I did the big look through on this really impressive site last night for a relatable article and did find quite a few. I did develop a couple of other questions in so doing. It would seem that some notable contributors are 800 – 1000 grit “color” sanding their ground coats.
Someone else said they use scotchbrite pads, red and gray for solid colors and metalics respectively. Did I read this right?
I would have thought that such a practice would knock the metalics this way and that in a most undesireable way. Some other great things I gleaned was the practice of letting solvents really out gas and not to get too skippy about mid coating and top coating with one custom painter saying he perfers to wait overnight to proceed. BUT! Isn’t there an open time in which the manufacurer recommends you get after it? So….that’s it. #1 Do you lightly sand ground coats? AND #2 Can you wait up to overnight to top coat without having delamination problems down the line?? Going to pick up the paint and more importantly the data sheets later but anything you guys would care to add is MOST welcomed. THANKS!!

[Ben Hart]

Ben Hart

June 20, 2012 at 7:35 pm #37346

Welcome to the site.

I have used ChromaBase in the past, it is a decent system. As for your questions, the panel to be painted needs to be prepped before basecoat (in this case, basecoat being ground coats and mid coats). Chromabase seems to hide scratches a little better than some other products and may even be able to cover as coarse as 400 grit dry. In any case, I would want the panel finished with 500-600 dry (on a DA) or about 600-800 wet. The tech sheet will read something similar.

As for application, apply your gound coats with adequate flash time between coats. Allow the ground coat to flash about 15-20 before proceeding to midcoats…DO NOT sand or scuff the ground coat. Apply your midcoats with adequate flash between coats. Allow a longer than normal flash before clearing, again, DO NOT sand or scuff the midcoat. As for flash before clear it depends on the number of coats, airflow temp etc. When I used Chroma base I usually waited about 45-60 minutes before clear just to be safe.

I recently saw a Cadillac I did tri-stage white with Chromabase about 3 1/2 years ago, still looks good and is holding up well.

On another note, did you read anything about let down panels for matching tri-stage colours?

[Philip Long]

Philip Long

June 30, 2012 at 5:20 am #37529

Hey, Ben.

Thanks for the reply. Yes, I did get a sheet on a letdown procedure with the data sheets. This is decidedly not as critical as matching a panel to the rest of a car as it’s a race car changing it’s livery from black to blue.
I did a test panel and sent it off for approval so we’ll see how we go….
Followed some of the procedural guiding I found on here and did wet 1000 before ground coat and a bit more flash time before clear as you suggested here and if the car results are as good as the test panel I’ll get a grammy award.
Who paints a race car in tri-coat anyway…?? Oh well. Mine is not to question why.

Thank you for the response! I may have other questiones in the future.

Cheers!

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