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Old 02-27-2010, 06:13 PM   #3021 (permalink)
dave koller
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Originally Posted by CamLight View Post
Unfortunately, as I understand it, it can't be done DIY very well. It takes a lot of current and requires a very carefully controlled temperature bath. Otherwise, it's pretty well the same process used for the colorful anodizing often seem. It's just a lot tougher. Half the hardcoat anodizing actually sinks into the pores formed by the acid bath (typically 1/2mil deep) and half sits on the surface (typically 1/2mil thick). What's on the surface forms the "insulation" and is incredibly tough. Do not plan to do any machining or drilling of a hardcoat anodized piece of alumunum! It will eat up your bits.

But, a large number of anodizing facilities can do Type III hardcoat anodizing (the military uses it a lot). The only problem is that it comes in only one color, dark gray/black. They typically charge a lot fee for a basket full of parts. The more parts you send in at a time, the less expensive it will be for each part.

If you don't have a lot of parts (100+), it can get expensive. But, if you're pushing the thermal envelope for a design and can't have a "hot" heat sink or use mica or thermal pads between the MOSFETs and heat sink (because of their high thermal resistance), hardcoat anodizing is the way to go.
LOL yes you are right - but we have done it here Raceline Oil Pumps, manufacturing dry sump oil pumps and accessories for race engines.

I know because I worked on the DC supplies - and they do all the Type III in an old freezer with external pumps and cooling ( cooling is the key and great regulation of the current!) -- I guess DIY gets serious with some people.. It definitely is not as easy as the "anodize in a 5 gal bucket" with temp probes - but we all have done the impossible here - but CamLight is right - easier to find someone to do it...

Dave ...
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