Problem Solving Forum

November 21 - December 4, 2011

How do you measure the DFT or WFT of a film-forming sealer applied to a metallized coating (e.g., flame-sprayed zinc)?

Selected Answers

From Simon Hope of Bilfinger Salamis on November 30, 2011:

     The answer is in the q more

     The answer is in the question! For TSA (Thermal Sprayed Aluminum), we are looking to seal an inherently porous material. The sealer coat is there to fill the interstices but not to create any particular build. The amount of sealer applied is dependent on the level of porosity and thickness of the TSA as well as the solvent content of the sealer coat.

     Guidelines are given by manufacturer, but these are only ballpark figures to form the start point for application. Normally, a sealer is applied just enough  to create an apparent wet film, which will dry back into the profile as the solvent evaporates, thus coating the bare metal as well as providing a tie coat for subsequent higher volume solids coats. Consumption can, if required, be calculated in area per unit volume, and from that, it is possible to approximate to WFT and DFT, though, in reality for this process, these are pretty meaningless and the visual appearance is more relevant. Coating integrity is the primary objective, and a good applicator will produce the visually correct sealed substrate, which can be confirmed by the material consumption.

From Gunnar Ackx of SCICON worldwide bvba on November 22, 2011:
     You can't. A sealer for s more

From David Lemke of Team Industries, Inc. on November 21, 2011:
     I have used the theoretic more

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Tagged categories: Coating / Film thickness; Dry Film Thickness (DFT); Quality Control; Wet film thickness