Corrosive Effect of Aluminum clamp on steel barrel?

[h34choctaw]

I have a 20 gauge shotgun with rib and have not found any clamp that will work on the barel with rib installed. I am thinking of using an AR15 gas block with rail, machine a slot for the barrel rib, and mount it upside down to make a picatinny rail attachment for a flashlight that will keep everything in-line with the mag tube which will give the shotgun a slim profile. I am wondering if I should use a steel or an aluminum gas block. A .750 block will have to be bored out .001-.002" which is no biggy and I might even bore it out just big enough tobe able to freeze the barrel, heat up the gas block, slip fit it on, and when it thaws it will be nice and tight. The aluminum will be lighter of course (and cheaper) but I am wondering what kind of corrosive effect it will have on the steel barrel. I know bare aluminum and steel will corrode when in contact with each other but what about a blued steel barrel with an aluminum gas block clamped on-how bad it might get? Scope bases are aluminum and usually there are no problems...what do you guys think??

 

[FbodTrek]

Anodized Aluminum doesn't set up oxidation like raw aluminum does. 99% of aluminum firearms accessories are anodized.
If the block you plan on using isn't anodized yet, it's a VERY simple process you can do at home, with little more than some battery acid from auto parts store, some aluminum wire, and a DC power supply of some sort (like a car battery charger), colored dye of your choice and some distilled water.

 

[1coolhand]

Anodized Aluminum doesn't set up oxidation like raw aluminum does. 99% of aluminum firearms accessories are anodized.
If the block you plan on using isn't anodized yet, it's a VERY simple process you can do at home, with little more than some battery acid from auto parts store, some aluminum wire, and a DC power supply of some sort (like a car battery charger), colored dye of your choice and some distilled water.

Good info!

 

[Brian618]

If you get down to bare aluminum on the gas block and remove the anodizing it can increase the chances of galvanic corrosion. I would recommend hitting the gas block with cerakote or some other proven coating to minimize the risk. Even with bare aluminum, the odds of corrosion are pretty slim unless the gun is exposed to a lot of moisture.

 

[07JKX]

most informative thread on the ODT in quite a while. Just learned a ton of new info. Off to google I go

 

[h34choctaw]

Thanks guys-really appreciate it. I will post pics and info when I get this project done.....and my wife wonders why I never finish off the front porch!!!