Protection of surfaces that must stay uncoated, such as bores, threads, seal grooves and datums. Blast masking uses tough rubber or vinyl tapes and plugs to resist abrasive, while spray masking uses heat-resistant aluminum foil and glass-cloth tapes, silicone plugs, liquid maskants and reusable metal shields. Masking often takes more labor than the spraying itself, and poor masking is a leading cause of rework.
Masking on the blade roots takes longer than the spray, so book the hours for two people.
Use separate masking for blast and spray: blast tape keeps grit out but melts under a plasma gun, while foil tape survives heat but tears under grit.
Also heard as
- mask
- maskant
- masking off
Related terms
Tape
Masking tape used for blasting and spraying, or as a verb, masking a part off before coating.
Bridging
Coating that forms a continuous skin across the edge of a mask, so it tears or lifts when the mask comes off.
Overspray
Spray material that misses the part or fails to stick, ending up in the collector or on nearby surfaces.
Line of sight
The limit that thermal spray coats only surfaces the gun can point at directly.