Where can I find an exact discription of the type III anodizing process.

I always read that it is not done at home because of the high current and low temperatures required.

I have ac and dc welder both capable of 300 amps.

As for cool temperatures, dry ice can be purchased at a local store for a resonable price (dry ice has a surface temperature of -109.3 degrees F ).

If these are the only requirements that differ from type II anodizing (high amps and low temperatures), the process could be done at home..... or is the something else I should know?

Thanks .... Mike

Start reading here - you may find something there.

Caswell

Yes, same here.  Was thinking of the same question.  

I'm not sure about Caswell having a type III finish, although they claim to conform to MILSPEC 8625F which is what Bushmaster claims for its finish as per their catalog.

Frontsight

The bulletin board could provide you with some educated discussion on the topic.  I haven't spent much time there, but I may in the future.