Help on Putty Work

I'm doing some serious work on my Dodge Ram and I made a air vent on the hood. But I can't seem to get a smooth job. I put primer over it to see, and there is some small imperfection that I can't seem to get away.

Is there a technic or a special stuff to make it smooter ?

thanks

Try to break down the putty work to several steps, when using putty to alter/add new part or shape. Use coarse sand paper like 300-600 grit to achieve the basic shape every time you add putty. When the final shape is obtained, use finer sand paper like 600-1000 to remove the scratches. If the desired part is thick, epoxy putty is more appropriate, but it takes time to harden. Polyester putty is also good for building a thick volume, and it hardens very quickly.
I don't think primer would smooth the surface, unless it's thoroughly sanded, but it will make the surface texture consistent.

no i use primer to see the work.. With grean putty, wWhite plastic and gray primer, it's hard to see imperfection, so I make a light coat if primer and I saw imperfection

I sand with 300 and 1500 grid sandpaper.. but i can't get a smooth surface (it's smooth at the tutch, but no to the eyes)

sorry for my english

have you tried coating the area with a coat of Future Floor Polish? I just got the stuff a while ago and it works like a charm to fill in small imperfections..... just put one or two coats on with a cotton swab or something, and then sand the heck out of it.... then one more coat of primer and it'll probably be very smooth by then....


but test it out first of course...

I think you have to make sure your sanding surface is rigid and flat...
I always use either emery boards or wrap my sandpaper around a ruler. Just sanding by hand doesn't leave a perfect surface. At least, that's what works for me.