I had to write a report this week at work about a new line of studio microphones we produce that a painted finish is being considered for... I copied parts of it for suggestions to prevent unwanted outcomes...

Here are some highlights;


-Material MUST be exactly, properly prepped before finishing (proper cleaning/de-contaminating/roughing up etc)...

-Finish chosen for application must be durable, scratch/abrasion resistant, sets well in a reasonable time, applies evenly, and is resistant to chipping/gouging (during assembly & end user use)...

-High performance coatings (like powder coating) usually require heat baking curing (powder coat processes vary, but 400deg F /10 min is common for other applications)...

-Finishes tend to be thin, brittle, and taut on surfaces... Material that is thin or somewhat flexible can strain it's hold between it's finish layer... Areas like corners, edges, raised areas etc are under more finish tension, thinner, and tend to make contact with external objects more that cause them to wear more rapidly...

-Assembly issues include when tensions are applied to finished parts (such as screwing down parts, areas around screw holes, clamping parts etc can cause chipping, cracking, and other
issues)...

-Parts are exposed to high heat during curing processes... This can effect parts fit tolerances (heating causes metal to expand and upon uneven cooling , there can be local deformation that can
allow thin materials to to buckle, wave/distort, and create tensions that can reject finish coat...

-Pre-finished surfaces not properly decontaminated can leave residues that can affect finish adhesion, or if they out-gas during curing, they can blister, chip etc...

-Some production processes containing solder (such as attaching frames to mesh screens) are close to melting temperatures used in the curing step, and can melt the solder if oven temp gets slightly higher than normal... Uneven heating/cooling can cause uneven finish surfaces or unequal tensions in finish or parts...

-Some finishes hold handling fingerprints, body oils/acids well, and can penetrate finish or part surfaces...

-Powder finishes are porous, and if over steel etc, can allow excessive moisture/humidity or environmental issues to penetrate, and possibly cause internal corrosion eventually, affecting finish &
material...

-Finishes "soften" the visual lines of a product's appearance, and light reflecting from a finished surface can change it's color/hue, possibly causing a different effect than the base color...



Recommendations:

-Look at pros/cons of different finishes...

-Thorough review with vendors, research regarding the type and application of a finish, and the effect (finish & process) on parts...

-Pre-checking test samples for resistance to chipping, damage, during test assemblies, and short/long performance tests to see how they survive different assembly processes and field use...



Just a head's up that might keep life happier/easier for us all!!! :-)


Not too different for foto gear, just other considerations to consider!!!

Steve K