Iron Brigade

More of a tip for other gamers to get this achievement as youo can get this eventually as you grind for your level and complete the game or more efficiently repeat mission 1 or mission 2, have a assault chasis that can hold up to 4 weapons and preferrably a leg chasis that have quick reload or sprint. Preferred weapon of choice are machine guns with shred or shred + (give more scraps/tubes) now only place support emplacement damper turrets near where you started and when the enemies come just fire away this way you get more scraps/tubes. Finally, if the ionzed scrap collector turret is available deploy them to collect the scraps more efficiently. Thanks.

Note: not to worry if you see that you have already reach more then 10,000 scraps collected and achievement did not pop, just replay another round and after collecting a dozens more scraps the achievement should pop mine pop roughly at 10,532 scraps.

This can be done on coop but the player going for the achievement need to be the main scrap collector and the coop partner/partners stay away from drop. Again if everyone have a shred/shred+ machine gun helps alot to generate extra scraps from kills and recommend train mission or mission with alot of enemies coming directly at you from spawn or with clear sight as that way they are easier to kill and for your partner to as ally will drop extra scrap to assist Rinse and repeat, not to mention that you can get at least 2-3 loot box drop.