Seeking info on Type 3 Hard Anodizing

[jepp2]

I'm considering finishing an 80% lower for an AR15. If I do, I want to get it type 3 hard anodized. What is your experience with:
1. The cost and who you used to do this work?
2. Legally what I need to do to send it out for this work.

I seem to read a lot of different opinions on this, so I thought I would ask.

 

[mac86951]

Before or after completing the machining?

 

[jepp2]

After

 

[Scott Harris]

I've used these guys with great results: http://www.smf-az.com/ They are local to me with reasonable prices. I suspect every major metro area has a similar shop. Have you googled for local shops?

 

[mac86951]

After machining it's considered a firearm, ask if you need to do transfer. Depends on how the shop is set up.

Typically the cost will be high, chemical costs for the process are standard based on tank size. Best bet is to ask around and see if they have space to piggyback on another batch. Likewise ask for cleaning and surface prep recommendations as it's considered rude to contaminate a batch if you're not the only part.

-Mac

 

[wapiti25]

Send the lower before you "finnish it". It is not a firearm at that point just a piece of aluminum. The anondize can be broken thru and be machined as the base metal.

 

[mac86951]

Send the lower before you "finnish it". It is not a firearm at that point just a piece of aluminum. The anondize can be broken thru and be machined as the base metal.

Then you lose the wear resistance on the pivot points. Otherwise go for it

I guess you could do the cross holes first then anodize then finish it.

 

[TRA]

Make sure you send your lower to an anodizer that has an FFL. If you are not absolutely positive what the material is, tell them "material unknown". They can get in a real twist if it is not what you promised them it is. Make sure you leave enough clearance in pin bores and threaded parts or you can end up with parts that will not fit.

Figure anywhere from 100.00-200.00 for a short run. Or find someone to tag your parts onto.

 

[ireload2]

Mil A 8625, Type III hard anodize is about .002 thick. It builds up each surface .001 and it penetrates .001. So it will close a hole by .002 if you can get it to build up in a hole. Small diameter deep holes do not coat well because it is a process dependent on electrical current density. Basically it is a ceramic coating of aluminum oxide. This is the same material as the gray grinding wheels used to grind steel. It will destroy your tooling on a lathe or milling machine.
Before you use this finish you should become very familiar with the mil spec and what the application tolerance is and how it builds up on surfaces. Never plan on machining this finish.

 

[Ggmac]

Just got to know , WHY ? With the cost plus labor , I can understand the challenge of drilling a few holes , milling if you have one , but the cost to anodize just makes it an expensive project . You could buy 2-4 unfinished receivers and probably never wear out the first one .

 

[JRS]

www.omwcorp.com/understandingano/anoindex.html

The holes can be plugged.