Lack of anodizing in certain spots

[phixion]

About to build out an LMT lower. It appears the anodizing is "missing" in the holes for the bolt catch spring and buffer retainer.

Steel spring, "unanodized" aluminum, galvanic corrosion, etc. A valid concern? Is there anything I can prep the bare surfaces with to eliminate any potential issues?

[JediGuy]

Get it replaced if you purchased new not blemished. No reason to accept that.

Brownells had/has discounted LMT upper receivers for a while as Blems, because anodizing was missing from the takedown pin holes, if I recall correctly.

[phixion]

Get it replaced if you purchased new not blemished. No reason to accept that.

Brownells had/has discounted LMT upper receivers for a while as Blems, because anodizing was missing from the takedown pin holes, if I recall correctly.

True; you're right.

At the same time, I could care less especially since those spots wouldn't be visible with the parts installed. I am just unsure if could lead to potential issues in the future.

Sent LMT a message inquiring via their website; we'll see if they respond.

With they said, there are some smart, knowledgeable people on this forum. If one comes along and says it's a non-issue, I'll build it out and not give it another thought.

[P2Vaircrewman]

Galvanic corrosion between dissimilar metals is a problem when an electrolyte such as water is present. Oil is not an electrolyte, and hopefully you don't store it outside in the elements. Personally I wouldn't worry about it.

[markm]

Agreed. I wouldn't think a thing of it. Add some moly grease for extra insurance if you like.

[Joelski]

What Mark said. When ya lube the buffer tube and spring with spray-on white moly grease, lead a tiny overspray to the retainer pin and spring. That'll keep those galvanic forces at bay. It also helps a wee little bit with the "skee-wonk!" spring noise when ya shoot supressed, for a hundred bucks less than a captured spring.

[lysander]

Is the anodizing missing? Or, just the black dye?

[alx01]

About to build out an LMT lower. It appears the anodizing is "missing" in the holes for the bolt catch spring and buffer retainer.

Steel spring, "unanodized" aluminum, galvanic corrosion, etc. A valid concern? Is there anything I can prep the bare surfaces with to eliminate any potential issues?

I might be in the minority, but for such a non-critical areas I would personally just spray it (or Q-tip) with ALUMA-HYDE and move on. LMT has an excellent customer service and will replace it if you want to go that route. Maybe they have some recommendations on a home-fix. I would be interested in learning about it from the manufacturer.

[Tx_Aggie]

Is the anodizing missing? Or, just the black dye?

I was wondering the same thing. Does LMT Anodize or Ceracoat their receivers?

If the lower was anodized after the holes were drilled I would think it unlikely those surfaces were missed by the plating process. More likely they just didn't receive enough dye between anodizing and sealing for the color to set.

[phixion]

Thanks for the replies.

I attempted to take some photos of the areas in question: https://imgur.com/a/XHkPVbo

I'm completely ignorant on the anodizing process, so I'm not sure exactly what I'm looking at. The "black color" reaches a certain point, then it appears white/chalky (aluminum oxide?) and then at the very base of the hole, it appears to be silver. It very well may be a lack of dye as some are suggesting; most likely.

Again, as I understood it, steel spring, aluminum receiver, dissimilar metals, possible corrosion, etc. I just decided to pose the question before proceeding.

As others suggested, I'll likely just put some moly grease in those spots, install the parts and not give it a second thought. I figure once the parts are installed, they should be sealed fairly well from any moisture.