Paint does not cover

[khan.cross]

Guys this is my first thread, I am a user from Germany and working on a project, painting my motorbike in matte black. Have some experience with painting as I painted choppers before. I always use spray cans, mostly from the same manufacturer and same paint series.

I am trying to figure out what causes my current problem which is, that the paint does not cover, the primer shines out after drying of the base coat. The primer (gray) and base coat which is also the final coat (matte black) are from the same series of same manufacturer. What I did is:

1. Cleaned the motocycle plastic parts
2. Sanded them with 240 grid
3. Degreased them
4. Primer
5. 24h Drying
6. Sanded with 1000 grid
7. Put base coat on, matte black. Many many layers because after few minutes of dring the primer was shining thru. As longer the base coat dries, as much the primer comes out!

Please remember the parts had the factory paint, I just sanded them, but not sanded the paint away.

Any ideas why this happens? Where is all the paint going to? I used for two parts 6 cans, usually 2-3 are enough.
Attached are photos, taken around 2 minutes after putting a layer matte black on.

Thanks for support

 

[TAZ]

It's hard to tell from the photos what's going on. It doesn't appear it's a coverage problem as the primer appears to be 'spots'
I don't know if the parts were previously painted. Possibly the degreaser bit into the paint and softened it, so the primer and spray can did not work properly.
You should really use a degreaser first even before sanding
You can use a mild pre-paint cleaner before painting

OR, the paint is just blushing in spots and it only appears to be the primer when in fact the black is blushing, so it turns gray.

 

[chopolds]

Being in Europe, I believe you still have lots of access to lacquer paint. Might be lacquer "blushing". Happens when you shoot lacquer when it is raining, or even humid out.