Today we’re doing a Marines globe and anchor roll-mark for a customer’s 80% AR. He didn’t want to refinish the lower so we applied some Birchwood Casey “Aluminum Black” to the engraved area. This worked out well because the surface area of the engraved lines was small so the Aluminum Black was able to fully coat (it tends to look blotchy / patchy if you try to apply it to a larger area, but it’s great for engraved fine lines, scratches, etc.
Marines roll-mark on an 80% lower. Fresh off the laser with no coating (wiped dry with a cloth). This was engraved relatively deep compared to the width of the lines because the customer planned to either cerakote or otherwise fill in the lines rather than leave the raw aluminum exposed.
The Birchwood Casey “Aluminum Black” nicely filled in the fine lines of the engraving and very closely matched the finish of the lower. The engraved area of the lower was cleaned with brake cleaner spray and dried, then warmed up with a heat gun. The Aluminum Black was then applied to the engraved area and allowed to sit for 30 minutes, then rinsed off with cold water. The product worked very well in this case because the lines were narrow and had a small surface area.