Practical consideration over loss factor in coating application project

Coating loss factor consideration is very important while considering any protective coating project as it directly impacts on the profitability of the coating business.

Mr Maheshkumar B. Aradhye, Associate Vice President - R & D, Grauer & Weil India Ltd.

Abstract: There were many different views about the considering coating loss factors and the practical difficulty of estimation was arising due to lower awareness of the factors that affects the coating loss as it is dependent on many more factors. If we understand those variables clearly then it's very easy to estimate the coating quantities for the entire project.

Key words: SSPC-PA 2, Transfer Efficiency, Volume Solids, Blast profile.

Material costs: The number of litres of paint, thinner, cleanup solvents, etc. must be estimated based on the areas being coated and the dry film thickness (DFT) in microns of coating to be applied. Loss factors must also be estimated. Material loss factors, such as overspray, range generally from 10 to 50 percent of the total paint purchased, depending on weather job location, and conditions, the type of surface to be coated. The practical spreading rates are normally more useful than the theoretical spreading rate figures quoted in the coating manufacturer's product data sheets. The estimate should also include the cost of consumable supplies. Abrasives, cleaning rags, respirators and respirator cartridges, overalls and other protective clothing, masking tape, and small tools such as scrapers and wire brushes are all considered consumable items that are expended during the course of work.

Loss factor: This depends on many variables such as

A) Size and shape of surface: Smaller size of articles will have more over spray and being difficult to coat will have always higher loss factor whereas over bigger and flatter surface there would be bounce back effect while spray loss