Block Sanding For Beginners - Get It Straight

...There is also a concave area on the top of the fender near the windshield that was too tight for the thick block we were using on the side, so the thin block will flex enough to get into that space.

Running down the center of the fender is a bodyline that you will want nice and straight...

...The best way to ensure this line is perfect is to lay a piece of tape along one side of the line-the top in our case. Make sure the tape is straight as possible as you stick it down.

Now use your block and sand up to the tape. The tape will prevent you from removing material that it's covering. Sand until all the guide coat is removed.

When you have the guide coat off, pull the tape to reveal the straight bodyline. If you can't get all the guide coat off before you break through to bare metal, then you will need to hammer the low area of the line up or build it up with filler.

For high spots where there are no low spots next to them, you will need to use a hammer to move the metal down. Tap lightly around the perimeter of the high spot first then tap down the middle. Don't get all macho when swinging the hammer it won't take as much muscle as you think to move the metal this little amount.

Now it's taime to mix up some Rage to fill in the low spots. Before you pull any out of the can, slowly mix the filler. Don't mix it aggressively; that will just produce a bunch of air bubbles. Pull out a couple of blobs that will make about a 3-inch diameter spot on a non-porous mixing board.

Kneed the Cream hardener to mix the contents before laying a 1 1/2-inch long bead on the filler. Mix in the hardener completely with a plastic spreader until the color is uniform.

Spread the filler over the low spot as smooth as you can. The more you lay filler the better you will get at it, which will save you some sanding time. As you can see Vic spread the filler well beyond the low spot, this put enough material on the panel that you can sand off to make the area flat again. The bigger the low spot the larger the overage you will need to spread. Also, if the filler starts to harden while you are spreading it, just stop and let it dry. You can always knock it down with some sandpaper and try again if need be.

Once the filler is dry (about 20-minutes) start blocking with 80-grit. Don't put a lot of pressure on the block as you sand in the X-pattern. You are just trying to catch up with the surrounding area that was already blocked and it's pretty easy to take off too much material.

Once you are close (you can tell by running your hand over the area), spray some more guide coat and switch to 150-grit.

It only took a few passes with the block to remove all the guide coat without breaking through to bare metal. That let us know the low spot is gone.

Now the surface is ready to be primed, guide coated, and blocked again. This final blocking will be done with 220-grit paper on the same blocks used throughout the process.

If you have followed the steps, the last round of blocking should look like this. The guide coat is gone and there are no bare spots showing. Now just repeat these steps on every body panel and you will be ready for paint. If you are planning on a single stage paint job then just spray some sealer over the 220'd finish. If you are going with a two stage (basecoat/clearcoat) then you will want to remove the 220 scratches with some 400 and then remove the 400 scratches with 500. Then you will be ready for sealer and then your basecoat.