Mats for weapons is so easy to get. I got at least 30 spare gizmos and that number usually climbs.
Here are a few tips:
Obtaining:
1. Missions can reward gizmos, usually get 2 minimum.
2. Open every toolbox you see, go to places you think toolboxes will be (garages, industrial sites)
3. Complete side events with crafting rewards. There is a solid chance to get gizmos.
4. Chests can drop gizmos. Finding chests is a bit of a skill on it's own. Learn where they spawn (often times on roof tops or in basements, sometimes behind false walls - for example). You can also use the radar towers to locate chests.
Maintaining:
1. Instead of having all 3 slots with a crafted weapon, use random weapon drops you find as well. This will mean dying has less of an impact, since dying only damages equipped gear. And random weapons that are dropped are sometimes solid weapons, you can evaluate at a glance looking at their power level.
2. If your lack of gizmos is making current power level difficult, try taking it easy and going to an easier zone.
3. If you're dying too often, which really increases the rate you consume gizmos, try increasing your power level, or your survival stats. Make sure you've spent all your survivor xp and hero xp (secondary heroes are good candidates to upgrade too).
Some of the tips apply to more than just gizmos. Like getting a ton of crafting mats if you do every side event that rewards crafting materials will often get you everything you need.
