In this Instructable, I will show you how to mask off a particular area prior to sandblasting to protect it, in this case I will be masking off the emblem on a bike frame. This type of masking is ideal for aggressive sandblasting at a close range for long periods of time.
Step 1: Cover Area with Vinyl
Cover the area you would like to protect from sandblasting with vinyl (with adhesive on one side). Use enough vinyl that it covers more than the area you wish to mask.
Step 2: Shape Mask
Using a sharp blade, cut away the excess vinyl around the shape you are masking off.
Step 3: Cover Area with Electrical Tape
Mask the area again over the vinyl with electrical tape. Electrical tape will absorb a lot of energy which will prevent the tape itself from being sandblasted away. Without the vinyl underlayer, the adhesive on the electrical tape will embed itself into your metal which can be removed by hand sanding. I use the vinyl underneath because the adhesive on the vinyl does not get embedded as easily.
Step 4: Shape Mask Again
Cut away the excess electrical tape like you did with the vinyl previously.
Step 5: Sandblast Area
With these two layers of masking material, your project is ready to be sandblasted. Remove both layers after you are finished completely with your sandblasting.