Coating Air Conditioner Coils

Ask an Expert From: Products Finishing, ,

Posted on: 6/1/2001

Question 1: I noticed in your Q&A (September 2000) a response about coating air conditioner coils.

Question 1:

I noticed in your Q&A (September 2000) a response about coating air conditioner coils. I hold the position of electrocoat product manager for a paint supplier and would like to discuss with you the use of electrocoat in this marketplace, both current and future. J.S.

Question 2:

In your answer to S.S. (September 2000), you failed to mention the only two methods for coating air conditioning coils that will really work. No known spray system, either electrostatic liquid or powder, will coat a coil that is more than one row deep. We are an OEM manufacturer of HVAC/R coils and do our own painting. We have had all major paint and paint equipment manufacturers try this application. Only liquid dip or electrocoat can coat tight fins or coils more than one row deep. Yes, electrostatic liquid or powder may coat very wide fin spaced coils that are more than one row deep, but the paint is so thick that the coil loses its heat transfer efficiency. However, even then, the coil may not be coated in the middle. Consultants with answers like your September answer make it very hard for manufacturing people to convince upper management (who knows nothing about painting) that powder is not always the answer to everything. However, I do usually enjoy your articles. Keep writing. My problem is convincing management that you need a clean substrate to get a good quality finish. J.H.

Answer:

Okay, J.H. and J.S., have you two been talking to each other and trying to double-team me? You are both right. The electrocoat process will certainly apply paint to the second, third and other rows of coils in heat exchangers. Simple dipping will also work, provided there is not too much solvent reflux.

Costs are always important in finishing operations. You must finish sufficient numbers of product to justify the costs of an electrocoat system. The alternative to buying such a system is sending coils to a custom coater for painting.

J.H., if you promise to let me off the hook, I won’t tell your upper management about your “who knows nothing about painting” remark. J.S., I would enjoy meeting with you and discussing the electrocoating market. By the way, I was a research chemist at your facility, probably before you and electrocoat were born. However, just because I am older than you, doesn’t mean I am wiser.



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