80% Build Advice

[WaffleMachine]

I've purchased some 80% lowers that are unfinshed aluminum. Since I don't want my lowers to resemble fishing lures, I want to add some color to them. I have two questions:

1) Is it best to get these finished before or after I mill these?
2) Can someone suggest an affordable place in the South SF Bay Area to have them finished?

By finished I mean not anodized; I am going to perform machining myself. I also understand there seems to be a requirement to be present when finishing the fully machined lower.

[colossians323]

gunkote them or cerakote them after you mill them

[edwardm]

Buy a can of Alumahyde-II in your choice of color. Prep the aluminum. Apply Alumahyde. Bake or let air cure for 3-4 weeks. Just finished a lower using plain black AH and it came out nice. The tricks are 1) let it cure, 2) apply properly and 3) prep your base metal.

Prep choices are: acid etch or bead blast (some finishes call for an actual sandblast, they want a more roughed up surface for adhesion). I went for the acid etch. West Marine sells a small aluminum prep chemical kit for about $20 that will do at least 2 lowers, possibly 3. Since mine sat around for a long while, I did 2 passes with the first part (phosphoric acid) and then did my pass with the conversion coat (chromic acid).