AR anodizing...what is/isn't it? And am I screwed?

[pointblank4445]

So...on assembling some fancy dancy alloy upper receiver (non 7075), I have to thermal-fit the barrel. I've done this at least 2 dozen times.

On this attempt, I use a heat gun and fit the barrel. I leave the barreled upper to sit and cool. Upon return to torque the barrel nut, much of the lovely black satin finish is now matte, powdery and gritty and is flaking off to the touch.

Previously, I have been told by more than 1 mfg that when messing with anything outside regular 7075, that anodizing can get tricky, and while the dye may not take as well, it's still hardened and corrosion resistant.

Can anyone confirm that? Or did I completely f**k something up on the thermal fit and compromise the upper?

Just trying to figure out my next play be it Cerakote, re-anodizing, or just driving on with a quick rattle can job.

[Disciple]

V7 2055?

[pointblank4445]

V7 2055?

Negative; C405 I believe

[georgeib]

Hodge does tell you to thermal fit the barrel and "apply heat liberally." I would call them and ask.

[GH41]

Can you put up a picture? You said C405 but you didn't say it came from Hodge. It sounds almost like it was painted.

[georgeib]

Can you put up a picture? You said C405 but you didn't say it came from Hodge. It sounds almost like it was painted.

AFAIK Hodge is the only one making C405 uppers. But I'm not certain.

[Evil Black Rifle]

It is still hardened and corrosion resistant.

[Stickman]

So...on assembling some fancy dancy alloy upper receiver (non 7075), I have to thermal-fit the barrel. I've done this at least 2 dozen times.

On this attempt, I use a heat gun and fit the barrel. I leave the barreled upper to sit and cool. Upon return to torque the barrel nut, much of the lovely black satin finish is now matte, powdery and gritty and is flaking off to the touch.

Previously, I have been told by more than 1 mfg that when messing with anything outside regular 7075, that anodizing can get tricky, and while the dye may not take as well, it's still hardened and corrosion resistant.

Can anyone confirm that? Or did I completely f**k something up on the thermal fit and compromise the upper?

Just trying to figure out my next play be it Cerakote, re-anodizing, or just driving on with a quick rattle can job.

Where you hitting it with heat and guessing, or were you test fitting as you were doing it? It really sounds like you super torched it, then again, you could have a defective receiver.