I can almost guarantee you that the problem is either poor prep procedures, using inappropriate materials or both.
I agree with
@Cuda Al when he says don't use isopropyl alcohol.
I have been painting cars for 45 years, and I have sprayed a LOT of parts with spray cans. You said you used "3 different spray paint types on 3 different parts". You did not say what kinds of paint you used and you only mentioned one of the three parts you painted (a steering column). I assume you meant that the steering column was all metal parts. Were the other two parts metal or plastic? We want to help, but we need more information to provide Inteligent help. I will do my best to give you the benefit of my 45 years of experience. You can get EXCELLENT results with spray cans if you follow the same rules that need to be followed for a good paint job. Small parts or a whole car; you MUST prepare parts properly, use good quality materials and follow manufacturer's instructions. If you don't, you will have problems
1. Use the proper materials: I usually like to stick with one brand of paint when I do spray can stuff. That way you KNOW there will not be any unfavorable chemical interactions between different brands. My favorite brand of spray can paint is Dupli Color. Their spray can paint is truly excellent, and the cans have a great spray pattern. I usually buy it at O'Reillys or Advance auto parts. The Dupli Color high build spray can primer works very well. My second favorite is Krylon. I avoid Rustoleum. And 55 is too cold. Let's say your garage is 55 degrees. Leave the paints and parts inside. Then you can spray them in the garage and use a heat gun on low to keep the parts warm while the paint is drying. It is a pain, but 55 is a bit to cool.
1. Surface Prep:
Metal Parts: Clean the surface VERY WELL before doing any sanding. If you don't, you are just forcing contaminants deep into the sanding scratches when you sand. I clean with hot soapy water followed by a chemical cleaner. I use a good quality pre paint cleaner like Pre by Eastwood or the Pre-paint spray can cleaner by Dupli Color. Then sand the surface ending with 320 grit. Do any minor body filler work now ending in 320 grit.
Plastic Parts: Clean the surface thoroughly with soap and water and a medium bristle brush. Then clean with a pre paint cleaner like as mentioned above.
2. Primer: You need primer!
Metal Parts: Some people will say that it's OK to spray over existing paint. There is some truth to that, but if you use a good primer, you will never have any bad interaction paint problems. For metal parts, I use several light to medium coats of primer, let it dry and then sand it lightly with 320 followed by 400 grit paper. Always follow the directions on the can.
Plastic Parts: After cleaning the parts, use a good quality Adhesion Promoter (acts like a primer for plastic parts). I use the Dupli Color Adhesion Promoter. Always follow the directions on the can. Adhesion promoter is clear.
3. Painting:
Metal Parts: Spray a light coat for the first coat. You are not looking for ful coverage, you want a light coat for future coats to stick to. Follow the instructions on the can. Follow up with two or three medium wet coats using the time between coats listed on the can. To protect the parts, I ALWAYS spray on a few coats of clear coat; either gloss or matt depending on what you want. Make sure you use the same brand of clear as the color.
Plastic Parts: After spraying Adhesion Promoter, wait for the time listed on the can before spraying color. I always use Dupli Color plastic spray paint. It is formulated specially to be sprayed on plastic parts. If you can't find the color you want in Dupli Color, SEM plastic paints have a lot more colors, but they are pricey. Follow the instructions on the can. Always start with a light coat followed by a few more medium wet coats. To protect the parts, I ALWAYS spray on a few coats of clear coat; either gloss or matt depending on what you want. Make sure you use the same brand of clear as the color.
If you follow these steps, your parts will come out perfect. Feel free to PM me if you have specific questions.
