11-24-2019, 01:39 AM
I can see where FL is going with this.
Yes, dissimilar metals are a recipe for galvanic corrosion but they have to be in intimate contact and usually something to aid conductivity like water, or worse, salt water. Anodising on the aluminium upper acts as an insulator however so unless this coating has been worn off at the time of fitting, like if the mouth has been squared beyond the black anodising then galvanic corrosion is a non issue. Plus, if he occasionally cleans and we all use oils for that, and he's not getting it constantly wet or working out of the ocean then all is well. In fact, put too much glue or grease on the mating surfaces and in such a tight fit could work against a nice solid join. You don't want your barrel nut squashing a big goop of grease or glue up onto the shoulder as the extension pushes in. Like galvanic corrosion this also might not be an issue but I would prefer not to tempt fate with a nice square contact.
That said, I run a greased cloth quickly around the inside of the mouth and outside of the extension before fitting. So fine you can't even see it. Moly is going on the threads anyway so I figure a super fine coat aids it going in, and out again when it's time to change barrels.
Yes, dissimilar metals are a recipe for galvanic corrosion but they have to be in intimate contact and usually something to aid conductivity like water, or worse, salt water. Anodising on the aluminium upper acts as an insulator however so unless this coating has been worn off at the time of fitting, like if the mouth has been squared beyond the black anodising then galvanic corrosion is a non issue. Plus, if he occasionally cleans and we all use oils for that, and he's not getting it constantly wet or working out of the ocean then all is well. In fact, put too much glue or grease on the mating surfaces and in such a tight fit could work against a nice solid join. You don't want your barrel nut squashing a big goop of grease or glue up onto the shoulder as the extension pushes in. Like galvanic corrosion this also might not be an issue but I would prefer not to tempt fate with a nice square contact.
That said, I run a greased cloth quickly around the inside of the mouth and outside of the extension before fitting. So fine you can't even see it. Moly is going on the threads anyway so I figure a super fine coat aids it going in, and out again when it's time to change barrels.