Step 3: "Body Filler / Sanding"
Body Filler (with its hardener)
Wood piece (surface for mixing)
40 grit Sandpaper
150 grit Sandpaper
600 grit Sandpaper
Rubber Sanding Block
Protective Eye Glasses
Put your gloves, protective eye glasses and respirator. Mix very well a small portion of the body filler and hardener until you have a one color mix.
Here's my technique.
First body filler layer: Using the squeegee, apply body filler all over the part to give some body trying to let a smooth finish, let it dry some minutes (time depends on the amount of catalyst) until it is perfectly solid. Using 40 grid Sandpaper and the Rubber Sanding Block, sand it just to remove the sharp points and edges. Clean up the dust with the wet rag.
Second body filler layer: Apply body filler giving the necessary rounded shape of the part, and let it dry. Sand it with the 40 grid Sandpaper and the Rubber Sanding Block. After the surface is smooth, use the 150 grit Sandpaper and sand it again and you'll notice a smoothest surface. Clean up with the wet rag.
Third body filler layer: Watch for voids and imperfections, apply body filler to it. Sand it using the 150 grit Sandpaper. Clean up with the wet rag. Now you should have an almost perfect shape of the part.
Using the squeegee apply one very thin layer of Spot Putty to all the surface, as thin the layer is, the fastest it will dry. After some minutes with the Spot Putty dried, sand it using the 600 grit Sandpaper, Clean up with the wet rag again.
Use the dremel tool for line details, or any other kind of detail you need or want.
TIP: if you notice a deep void after applying and sanding the Spot Putty, fill it up with body filler, sand it, and apply again Spot putty and sand it. Is easier repair big or deep imperfections with body filler rather than Spot potty because of the drying time.