Paddlesaw - combination of paddle & chainsaw.Rakes can be found in big bucks hardware store and the car battery is on top of a dumpster in an alleyway behind the movie theater (near quarantine zone). Electric rake - combination of garden rake & car battery.Green spray paint is located on the garage roof (door in the back of the storeroom) while the pylon is a traffic cone, common around the quarantine zone. Air horn - combination of green spray paint & pylon.Newspaper is strewn around the streets while whiskey can be found in several areas, including the bar and the garage exterior. Molotov - combination of whiskey & newspaper.combination of box of nails & propane tank. A power drill is on a shelf in the same room as Katey while a bucket is located in the garage store room (near the ladder leading to the roof.) Drill bucket - combination of power drill & metal bucket.
Both are sitting beside the first workbench in the garage. There are 9 in total and will accumulate across multiple playthroughs. For the 'A bigger taste' achievement, you must build all combo weapons yourself at a workbench.