Prior to grit blasting, apply MACHBLOC™ HVOF masking compound to a clean, dry, oil-free surface by hand-molding the materials to the areas of the part that require protection. An average surface thickness of 2 – 5 millimeters should provide an adequate amount of masking.
The screw holes can be filled in providing you use a backing to prevent blow through. You can enhance adhesion to flat, featureless surfaces by molding “fingers” of MACHBLOC™ which would wrap around the surface to the backside of the part.
After molding, MACHBLOC™ is cured at 250°F for at least 25 minutes. The curing time should be extended on large parts to ensure the compound reaches the curing temperature.
The cured MACHBLOC™ has the feel of a hard but resilient rubber when cured.
After grit blasting and spraying the part, the MACHBLOC™ HVOF masking can be peeled away from the part. The screw holes can be cleaned by inserting a screwdriver and unscrewing the threaded plug, which was formed in place.
Toluene, propylalcohol, or MEK can be used to remove any remaining residue when necessary.