I painted my lights red last week and in the middle of clearing them right now.
When I did the redding part, I sanded the lens with 2000 grit beforehand, and I was left with a rough matte texture after about 5 coats with 30 min in between coats.
Today, I noticed when I sprayed the 2K Clear (now on my 3rd coat) after cleaning the lights again with soap and water, it's not making the surface that much glossy like how others did it. The matte is still there.
Anyway, I plan on spraying 3 more coats and then sanding/polishing them tomorrow, I hope that works because I wasn't aiming for the matte look.
UPDATE:
I went through the whole can and made the 4th and 5th clear coats medium-heavy. My lights now have a glossy, wet look. The only problem is there are dusts and small fiber things in between the layers, but I can live with that. I did some research and found out that I need to let the clear coat cure for at least a week before I wet-sand and polish it so, that will happen next week. Otherwise, I am very happy with Metalcast and Spraymax 2K rattle cans.
Here's a list of what I did, btw:
0. Taped the surrounding part of the taillight lens to prevent overspray.
1. Clean lens with dishwashing soap and water, allow to dry.
2. Sand with 2000 grit until surface is hazy.
3. Clean again with running water, let it dry.
4. (Optional) I used this
prep solvent from Automotive Touchup to make sure there's no oil left on the surface lens. I also have disposable microfiber sheets that I used to wipe.
5. Once dried, I sprayed Metalcast Red in this method:
3x Light coat+30 min in between
2x Medium coat+30 min in between
6. Tail lights looked matte and ugly, but I didn't have the Spraymax then, so I installed them back to the car and ordered the clear coat and waited for a week.
7. Today, I cleaned the lights again with soap and water, then the prep solvent. Due to the matte texture, the microfiber sheets left some tiny strands of fiber stuck to the lens. Removing them is a huge pain, so I just decided to live with it since they are not that much visible.
8. I followed the same method as #5 when spraying the clear coat. The lights didn't achieve the gloss I wanted until the end, which is why I was a bit worried before, but now it looks really glossy.
9. Next week, I will proceed with sanding and polishing them, using 1000 then 2000 grit, followed by
Novus 1 polish from Tap Plastics.