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

khancross wrote:Any ideas why this happens? Where is all the paint going to? I used for two parts 6 cans, usually 2-3 are enough.

A bit hard to see from the photos (too small) but to me it looks like moisture content in the air too high, resulting in entrapment in the paint. Additional coats would only make it worse.

You can try warming the panel in the sun for a few hours or gently playing the output from a heat gun on the affected areas. This may release the moisture, but if you've slammed too many heavy coats over it then the only solution is to sand it all off and start again.

Humidity can be a reason, the weather here is wet, not raining but the air is wet. I tried today again, in one hand the spray can, in other a heat fan gun. The paint is even now.

Today it is around 80% humidity.


However I wonder if there is a way to paint in such conditions. I have a garden tent but some areas are little open.

But still not sure if this is really the reason...

i'm with Chris on this, the picture looks like moisture from hi humidity. i'm assuming its lacquer your using, lacquer doesn't like hi humidity. you might try a couple heat lamps to warm the area, warm not hot. I had a friend that did nothing but Harley tins with lacquer spray cans. he built a booth on a table about 5' long x4'high x 3' deep he had heat lamps in the top part and a small fan at the rear. it work great for him, the work he did was spectacular.
Jay D.

That means the humidity is so high that the part, which needs to be painted gets wet quickly and the paint wont stick on the part as water is in between. Is this what you mean?

badsix wrote:i'm with Chris on this, the picture looks like moisture from hi humidity. i'm assuming its lacquer your using, lacquer doesn't like hi humidity. you might try a couple heat lamps to warm the area, warm not hot. I had a friend that did nothing but Harley tins with lacquer spray cans. he built a booth on a table about 5' long x4'high x 3' deep he had heat lamps in the top part and a small fan at the rear. it work great for him, the work he did was spectacular.
Jay D.

Can you arrange a photo of your friends paint booth and post it here please?

its hard to explain. but Lacquer collects the humidity or moisture in the air when its sprayed and then lacquer flashes to quickly, a lacquer trait. you can also use a slow thinner for this vary problem, but that's hard to do with spray cans. and no its not getting on your parts and making them wet. on the booth no he died 4-5 years ago.
Jay D.