if u want a quick good way...simply paint right over the coat u have now. Let it dry for like a hour (so its dry but still tacky) then spray paint again....repeat....then let it FULLY dry and do 1 more coat....then do a coat or 2 of clear protection stuff...and you will be perfect!
Take the gun completely apart and remove the grips and all the hard ware. paint each half like flatliner said and put it all back together. Very simple and excellent results. Giv'er the Krylon touch baby!
1. First you want to clean the object you're painting really well. I recommend using dish soap first, rinse it off thoroughly, and then follow by wiping the item down a couple times with Rubbing Alcohol. If you are not using Zinsser Cover Stain then you must remove all the paint from the object being painted, or at least scuff up the surface first. Wipe down the surface to get all the dust off, then clean it w/Simple Green and Rubbing Alcohol. Note: Throughout the paint period the item being painted must remain at a temperature of 50 degrees Fahrenheit or above.
2. Make sure the item is dry, and then apply your primer. Make sure you apply the primer (and paint) in VERY THIN COATS! I can't stress that enough. For a good paint job you must use several thin coats to achieve a good finish. It is best to start spraying to the side of the object, then move across the object and to the other side. You don't want to start spraying directly on the object; otherwise, you'll apply it to thick in the area's where you start and stop. If you use Cover Stain it dries to the touch in 30 minutes, and can be top coated in 1 hour. If you opted to use another primer follow the directions on the back of the can to a "T"!
3. When the primer is dry and can be top coated per instructions on the can, apply your desired basecoat color. Your basecoat color is what will show through the other colors, and will be more dominant. Again, apply several thin coats a few minute apart. Since you're using a dark color over top of white, it may take upwards of 10-12 coats to fully cover the object. Note: If you use Rustoleum paint you have within the same hour to apply coats. After one hour you MUST wait a minimum of 24-48 hours to repaint. The reason is that after the paints started drying it will cause wrinkles if you apply another coat. If this happens, sand down the surface, prime it again (if it's down to the bare surface)and paint again, this time waiting the recommended cure period.
4. After you have your desired basecoat applied apply the rest of the colors you wish to use. If you choose to leave your basecoat as the only coat, then let it cure. When applying the rest of the colors, do whatever pattern you'd like. There are many out there you can do so be creative. Once totally done, let the object cure for a minimum of 14 days. Once you do the primer and paint will become fused together creating a very strong bond. It will not achieve this bond until a minimum of 14 days. You will notice that the paint can scratch and chip off very easily within this time period. This is because the primer hasn't totally fused together yet. You also must keep the item temperature at 50 degrees Fahrenheit and above. Failure to follow any of these steps will result in a brittle paint job.