A short how to for block sanding. It's very important to prepare parts to the best of your ability before paint. I'm sure most know by now that things may look great prior to paint, but then find it looks really poor after a layer of paint is applied. Here is one way I prep machined parts to smooth ridges left behind by the cutting process.
I start by blending any high ridges or deep tool marks with a right angle grinder. DON'T be to aggressive! Deep gouges or waves end up causing more work.
Apply a layer of Dykem over the surface to be finish sanded. I prefer the shoe polish type applicator. The brush type ends up flinging on something and it never comes off.
Now take a piece of adhesive backed sand paper and apply it to a hard flat block. I normally start with 320grit and use a piece of 3/8" thick aluminum with a good finish.
Start by carefully sanding a bit and stopping to check your progress. Make sure you keep the block flat to the surface you are sanding. Don't be tempted to stray from keeping the block flat to the surface!
After a bit of sanding you can now see the low spots by where the blue Dykem remains. At some point you need to start using finer grits of paper depending on the finish you want to achieve. In this case I used 240/320/600.
Sand until all of the low spots are blended in. I usually spend more time with the 600 grit to slowly sneek up on the finished surface. Sanding is like sex, its probably a poor job if it only takes a couple minutes to finish. So take your time and do it good
Now you're all done and ready to paint the part. Normally I give it a coat of spray paint just to be certain the finish is acceptable. The paint can easily be removed with a quick soak in some strong paint thinner. If its good, get out the spray gun! In this case, its the color the buyer choose. Hope its the right shade. I think its fabulous!
