Here's my two cents.
- I've used Rustoleum 2x satin black and flat black on several builds with good success.
-The satin looks more accurate IMO, if you spray it too heavy it will appear glossier than if you do it in light coats.
-The Flat looks okay until you bring the pack into an outdoor sunlight environment, where it looks more grey-ish.
-I've had the BEST results by using satin and then rubbing the shell and parts down with ultra fine steel wool to dull it down a bit and get a good in-between look, that's what I would personally recommend.
The issue of metallic undercoat - I've seen so many build threads where this has gone wrong for people. The real movie packs had no metallic weathering on the shell, all shell weathering exposed primer grey underneath the black.
So not worth the risk and not accurate if you want to try to make it as close to the real thing. If you must do it, I would just do it to the resin parts that were made of aluminum on the packs in real life.
Texture - As far as I know most shells offered these days include a good amount of texture cast into the shell (GBfans, v330, nickatron, Chris Bosh shell ect..). If you really want to add texture I would recommend doing it with Chris Bosh's tutorial and the ceiling texture. I've done this twice on 2 non textured shells with great results.
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