It's been awhile since I have done any inventing but today I decided to work on it some. I sent my sim to the junkyard and blow up the scrap piles for some scrap.
I selected a pile and set the bomb. When it blew, it blew up everything in the junkyard. All 3 scrap piles, the items in the yard, the desk and chair in the office and the truck that's always in the parking lot. And my sims got burned in the explosion. Hard to hide when the whole yard blows up.
But I collected a lot of scrap from that one bomb.
I've tried it a few times and it's always the same. One bomb takes out the whole junkyard so be careful when blowing up the scrap piles. The bombs are more more powerful.
One time my sim didn't get burned was when after planting the bomb he ran out to the parking lot and the truck hadn't spawned back so there was nothing in the parking lot to blowup.