materials for rebreather construction

montyg

Hi there

May I ask why you add the teflon coating?

Also, is the teflon coating cheap or expensive, and how durable is it?

rgds
monty

Crazyduck

Hard Anodize tends to bring out a harsh surface- somewhat like a dull pain finish. The finish for Al6061 is usually a dark gray.


One of the problems with anodizing is the acid bath and it brings out all the imperfections in the surface. Scratches become very visible and apparent with finish. This can provide a surface for material to attach itself too. Also it needs to be noted that all holes must be masked for black or colored anodizing for the material will build up in the threads- additional cost for rubber plugs, or additional masking. There is an artesian touch to the processes and if done wrong the finish can come off or turns different colors. Black will often turn purple.


Teflon provides a slick surface and that impregnates the surface and provides additional protection. It goes from a dark gray to a deep slick army green.
The process makes the surface slick adds to the release nature and the ability to provide protection to the base metal. We use it in semi con parts for wafer fab and explosive proof equipment that has to go through wash down. The exception is explosive mixing kettles that stay strictly stainless steel because of contact with certain chemicals.

Is it expensive- depends.
Being in Dallas where there is competition for these processes can drive down the price. If you can send in a batch then they usually charge you a batch price verses per unit.
However, it does get pricy very quickly.
The Teflon is added process and not as well known and tends to be very pricy.
Per unit cost for anodizing, masking, wash, Teflon coating, packing- can run a couple of hundred dollars. If this is a process that you are thinking about chat with your different local vendors and try to find someone you get to know. They are always looking for people to work with and new business. Flexibility often can be the key- some clients are often on a screaming deadline and are a nightmare to deal with.

Hope this helps.
Best Regards, Andrew

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