What kinda sander you using? Lookin' nice and smooth!:thumbsup
You have to do a step up process. Its the same technique used for automotive body work and painting.
-When the bondo is partly hardened "cheesy" use a sure form to shape out the basic shape you want.
-Using a combination of electric sanders at 150-200 dry paper, sand the surface, followed by block sanding and hand sanding.
-Go back with bondo to fill in low spots, and sand again with 320
-Then got back and wet sand with w/d 320 paper.
-Clean the surface fully
-Using glazing putty fill subtle pinholes and subtle low spots. Once dry wet sand surface with 320.
-One the surface is to you liking, spray with gloss black paint. Once dry, you will see any imperfections IE low spots much better since it's a uniform gloss paint. Using wet 320 paper, sand off the gloss and repair low spots in need be.
-If no low spots or blemishes are present, use w/d 400 grit paper to sand the surface, do not sand too hard and do this by hand. You want the surface "cloudy" to give it a nice tooth for the primer to be sprayed onto.
-Once sanded and fully dry, use Filler Primer to spray over surface. Give it a nice thick coat or two but not so much as to make the primer collect and "sag".
-Once dry, using w/d 600 paper, sand surface of primer by hand, but do not press too hard. Once again, you want to have a nice even "cloudy" look to it.
-Once cleaned with prep solvent, and carefully wiped with a tack cloth, you are ready for paint. (I used 2 part automotive paint. It's more expensive but it sprays easier, and can be matched to any color needed)
-Spray on a very thin coat over the entire surface and wait a couple minutes for it to tack up. Now you're ready for laying down coats of paint.
-Once you have laid down as many coats as you plan (I did 3 with 10 minutes between each coat) Wait about 15 minutes.
-Now you're ready for your clear coat. DO NOT SPRAY CLEAR TOO MUCH OR TOO FAST!!! it will collect and sag and look very bad when it cures and be a pain int he but to go back and sand and repaint.
-give the piece a nice even coat of clear. I gave mine 2 coats.
-Let cure 24 hours.
**Note wear a mask while doing this as well in a well ventilated area that wont have floatys in the air or bugs to land in your paint. Also do not lean over you piece as hair and skin can fall into your paint.**