- The air and solvent can not easily escape through the outer surface without having any effecting action.
- Mineral spirit evaporates too fast.
- Fillet is coarse.
- The wood putty is not definitely dry, mineral spirit in sealer or topcoat is too strong, so it can penetrate into the soft putty and make the air bubble.
- Air bubble appears after stirring the material.
- The filter of spraying equipment is broken, so the water can go through.
- The wood is not dry enough, or it may absorb water too much.
- The finish surface is not clear enough.
* Fixing method:
- Avoid direct air flow.
- Use the kind of mineral spirit that evaporates slowly.
- Use fine Fillet to prevent water from penetrating into before topcoating.
- Use the wood putty that dries faster or let more time for wood putty to dry at higher temperature.
- Let the bubble settle down before application.
- Wash spraying equipment.
- Make wood definitely dry before finishing.
- Use rags damped into mineral spirit to clean wood before topcoating.