The work on the undercarriage continues now after the problems I had last fall. As the new paint did not stick to the undercarriage at all, I have to redo the entire project I started in the fall of 2015 once again. The car already looked fantastic when I found out that I have a problem.
The paint shop wanted to have the undercarriage media blasted this time, to make sure that everything is 100% clean, and that the paint can stick to the metal much better due to a rough surface.

Personally I´m not a big fan of media blasting a non disassembled car, as so many things could go wrong and I do not recommend to do it to anybody else.
The paint shop really wanted to go this route though, and they said that they have a very experienced media blaster to perform the work.
They did tape the car for hours to make sure that the blasting media would not go close to any mechanical or fragile parts.
The blaster worked with very low pressure (1bar - 14psi) to get the old paint off and it really came off within minutes. He did not want to risk anything and so there were some areas with the old paint left after he was finished.

We then spent a whole day trying to get rid of the rest of the remaining paint, by hand. With 240 grit paper we worked on all the areas we could reach. After a whole day under the car it was clear that we could not reach all the areas and that the job would not be good enough.

I then contacted a dry ice blaster who took over to remove the rest of the remaining paint. Normally you cannot remove paint with dry ice blasting, but as the paint on my car´s undercarriage does not stick, it works. It took him a couple of hours to get everything off.
The undercarriage is now completely clean and back to bare metal once again. He even was able to remove some of the old undercoating in the rear wheel wells which the other dry ice blaster could not get off.

We will now degrease everything multiple times and then scuff all the metal. Then its time to mask all the necessary parts and repaint everything once again with 2k paint. I will keep you updated here on my website about the progress.

The media blaster at work

Media blasting the undercarriage.
The bare metal wheel housing after blasting. The rest of the paint was removed later by hand and by dry ice cleaning.
After blasting

Ready for dry ice cleaning.
The dry ice cleaner managed to get the last undercoating out of the rear wheel housings.
Dry ice cleaning

Everything is perfectly clean now.
All the suspension parts were perfectly cleaned as well.

Tags:1974 Cadillac Coupe DeVille, 1974 Cadillac Repair Tip, 1974, Restoration, Dry Ice Blasting, Dry Ice Cleaning, Sandblasting, Underbody, Undercarriage, Media Blasting, Sand Blasting