Supplied thickness and coverage are different checks
A fictional coating exercise supplies an ideal dry-film target of60 micrometres and a volume-solids fraction of0.50. It also gives a net area of80square metres and a stated practical spreading rate of8square metres per litre for each of two coats. The practical rate already includes its specified normal application loss. A learner multiplies the required litres by another unexplained loss factor and claims that a touch-dry surface proves full cure. No equipment is operated and no actual product is specified. The reviewer asks for separate thickness and quantity calculations, a clear statement of model assumptions and recognition that the manufacturer’s actual recoat and full-cure conditions cannot be inferred from how a small surface patch feels.
1. What wet thickness follows in the ideal model?
Read the worked answer
60/0.50=120micrometres; this supplied ideal model is not a universal product specification.
2. What volume follows from the supplied practical rate?
Read the worked answer
80×2/8=20litres. Do not add the same included normal loss again, and distinguish touch-dry from recoat and full cure.