You can read Part 1 here.
Something I forgot to mention in Part 1, ideally bits and pieces of salvage would be represented by cards, which can then be mixed and matched by the players with (hopefully) minimal fuss. Also, the idea is to cycle through salvage cards at a steady pace. The PC’s items should break down, and either be repaired with new salvage or replaced with completely new items using a steady supply of cards.
Also, the system is designed with something like Swords & Wizardry Whitebox in mind, where all weapons do 1d6 damage.
Weapon’s are classified by a stat called Weapon Class (WC – term I’m borrowing from old school Gamma World). Each point of Weapon Class adds +1 to hit and damage (think magic weapon bonus). So, just a base (B) weapon has a WC of 1. Each additional piece of salvage added (A, C, D and/or E) increases WC by 1, to a max of +5.
However, when attacking, a result on the d20 roll equal to or less than the weapon’s WC means the weapon is damaged. The player chooses one of the enhancements that breaks, fails, runs out of ammo, etc. Obviously, the player will pick an A, C, D or E salvage over a base (B) salvage (otherwise, if the B item breaks, the whole weapon falls apart).
Example: A character has an M-4 Carbine (B salvage). Right now it’s essentially a club. But they have some ammo (Consumable) for it as well, and a scope (Attachment). The PC also welds on an improvised bayonet (Extra), and adds a touch of bling for style (Detail). Now the weapon is WC 5, adding +5 to attack and damage rolls. Should the player roll a 1 – 5 on a d20 when attacking, one of the pieces of salvage breaks (player’s choice). If the player chooses the Base item, then the whole weapon breaks (because you always need a B item), so the player would probably choose to loose the A, C, D or E salvage instead.
As you’d probably guess, each piece of salvage increases Armor by 1. At this point I’m undecided whether each +1 increases Armor Class (in the traditional D&D sense), or acts more as damage reduction. I think it’d work well enough either way.
When attacked, if the attacker gets a Natural 20, one piece of salvage breaks off the armor, reducing its effectiveness. Again, the owning player gets to choose which piece, and probably should pick A, C, D or E salvage over a Base item.
Tools could work in one of two ways, depending on your system: 1) each piece of salvage added to an item grants +1 on a relevant d20 skill roll over a target DC (the D20 mechanic); 2) each piece grants an X-in-6 chance of success at a relevant task (OD&D style). Again, tools could break down on a bad roll, as weapons and armor above.
Compounds work a little differently. They are made by combining only Consumable salvage, effectively representing one-use “potions.”
A minimum of three Consumables have to be combined to create a compound. When any three Consumables or combined, roll to determine the result on the Lesser Compounds table. Record the result, as this now becomes a permanent recipe in the campaign and can be replicated any time the PCs combine the same Consumables.
Combining four Consumables permits a roll on the Greater Compounds table, and 5 Consumables allows a roll on the Forbidden Compounds table.
Compound results include things like healing effects, toxins and anti-toxins, mutagens, various explosive compounds and the like.
At the GM’s discretion, the initial roll for a new recipe can be kept secret until the PCs have a chance to experiment with the new compound to see what it does; death and hilarity ensues. :)