TWI Frequently asked questions
by Suman Shrestha
The main disadvantage of flame spraying is the level of coating quality.
- Coatings tend to have high porosity (10-20 vol%), low density and high oxide levels (10-20 wt%) for metal deposits, and lower bond strength than coatings prepared by other thermal spraying processes.
- Flame spraying requires line of sight to the surface being coated, similar to all other thermal spraying processes. It is difficult, or impossible, to coat inner surfaces of small diameter bores and other restricted accesssurfaces.
- As with all thermal spraying processes there are particular health and safety issues that need to be addressed. For flame spraying these relate to protecting the operator from powder, dust and fume. Also the use of flammable gases,including acetylene, requires that safe use and storage of gases be considered.
