preping fiberglass bumber

[94GTMOOSE]

i am going to atempt to prep and paint a fiberglass bumper for my buddies car. Its not a mustang, so i figured if i do a bad job its not like its a nice car.

I am pretty sure that i know in theroy how to do all the work, I just need some help filling in some holes where i don't know what to do.

I am going to sand the whole bumper with 80 grit sand paper till its as close as i can get to smooth all over. Then i will cover the entire bumper with filler, and sand again with 80 grit. After that i need to put primer on and wet sand with 220. the primer again and wet sand again (should i go finer then 220)

thats where the procedure gets a little sketchy to me. should i paint after i sand the primer again. after i paint what grit paper should i use again. how many coats. what psi should i set the regulator at.

 

[88BlkStngGT]

Preparation depends on finished product desired. If you are using basecoat/clearcoat system use this procedure:
Sand entire assembly with 80 grit (as you described)
Sand filler with 80 grit production paper( the brown stuff), finish sand for primer with 150 or 180 production paper
Prime with 3 to 4 coats 2K acrylic urethane primer
Allow to cure at least 4 to six hours, then block sand with 180 grit, fill imperfections, then prime again
Block sand with 400 grit wet or dry (black paper)
Wash entire assembly with soap and water, let dry (you can use a blow gun and clean towel to speed up process) de-wax and paint.