I would most certainly have the character use checks to gather materials and make the items, I’d probably give him a quick rundown of what kinds of things are abundant in the area (like gunpowder materials (potassium, coal, sulfer) would be fairly abundant in the mining city of copperwood) then he’d tell me what he’s looking for and I’d tell him what the obstacle for that would be. As long as he’s made the widget before, there probably woldn’t be a chance of outright failure during construction, I’d probably just make him work into the night and end up tired in the morning or make the items “Unwieldly”.
The thing is the player wants to use the doodads in place of having weapons (and plans to act as though he were a wizard in front of characters that don’t know any better.) So far he’s been using them to aid in excaping and avoiding combat, but he’ll eventually get into a fight and he doesn’t have fighter or hunter or any other weapon.
It’s not like he’s throwing a knife or using a sling, actions where aim and the power of the throw are a factor, with most of these things he shoudn’t even have to come close to hitting the enemy, the deciding factor would then be how well-made the induvidual item was, which is how I’ve so-far excused testing Scientist durring a fight. If he’s caught in combat unarmed he’ll either depend on his patrolmates to attack and feint, or he’ll have to roll Nature or beginner’s luck for fighter/hunter.
I figure most of the items would have the thrown range rules.
The more I think about it the more I like having the gadgets be infinite and using twists to get them wet or have the character fall on them or otherwise ruining them.
For some specific examples:
ingredients: things like paper, alchohol, any container, fairly easy to find in most towns, especially sprucetuck.
construction: it shouldn’t be an extra test if he’s just jerry rigging one smoke bomb in a bar, but if he’s making a weather-ready supply, I’d say ob 2 Scientist.
combat effect: +1D to Maneuver +1s after successful Maneuver.
ingredients: crude patroleum oil/“naphtha”, container, very hard to come by, exclusively in large cities, especially coastal.
construction: finding the ingredients will be hard enough, construction is a matter of properly sealing the container, Scientist ob 1
combat effect: +2s after successful Attack
Liquid fire cannot be put out exept by smothering, using it carelessly could be dangerous for everyone.
ingredients: any of various venoms or natural poisons and a breakable air-tight container, fairly easy to find even outside of towns.
construction: the matter of causing the venom to vaporize would be a dificult feat of chemistry, so ob 4 Scientist.
combat effect: test Scientist for attack and feint.
ingredients: aluminum/magnesium, potassium/ammonium, fairly hard to get other than from mining or science cities.
construction: This is something that has to be measured out precisely or it’ll be a dud. ob 3 Science.
combat effect: +1D to Maneuver and Defend +1s to oponent’s successful feint while defending?
Again, I’m just throwing out ideas to be discussed, I’m not used to the balance of the engine.