[txsporter]

I was wondering what the A2's rear sights are made of. I have a worn set and I want to parkerize them, but I can't unless they are made of steel. If they are made of aluminum, I could destroy them if I try to park them.

 

[MikeG]

See if a magnet sticks to them?

 

[Lyman1903]

IIRC most all the parts are steel ,

except the elevation wheel (that is 2 part piece , lower part IIRC is steel, upper part is alloy) and the windage knob is alloy,

 

[txsporter]

How are these parts to be finished? Did they get their color from anodizing?

 

[dfariswheel]

The sight parts that are steel are given a Manganese Phosphate "parkerized" finish.
This is a much darker gray then the older Zinc Phosphate parkerized finish.

Only aluminum can be anodized and dyed.

 

[Lyman1903]

The sight parts that are steel are given a Manganese Phosphate "parkerized" finish.
This is a much darker gray then the older Zinc Phosphate parkerized finish.

Only aluminum can be anodized and dyed.

exactly,

fwiw, I just took a small magnet to a couple extra A2 receivers I have,

the lower portion of the elevation drum is steel, the upper portion (numbered ) as well as the windage drum are alloy,

the rest of the sight is steel


all the steel parts are manganese parked (darker than Zinc) and the upper is a matte black ,the knob and elevation alloy parts are not as matte

 

[txsporter]

How is the alloy made darker?

 

[Lyman1903]

How is the alloy made darker?

anodized that color

 

[dfariswheel]

Aluminum is finished with a hard, clear coating called anodizing, which is then dyed the color desired.
The anodized finish is known as Type I, IB, or III, with the Type III the hardest and the most receptive to the dye.

Cheaper AR-15 rifles may have the softer non-military specification anodizing. This leaves the parts with a softer, more easily worn finish, that the dye can rub off of.
If you see an aluminum part with a slight purple tint, it's not Type III mil-spec anodizing.