a mod like aucationeer can give some insight for your armorsmithing. Unfortuanaly with the fine art of explosives the game offers no "Rare" items to make super cheeze off of(well you can make some dang good cash selling Goblin jumpercalbes - XL, becasue most folks realy want the death ray and go gnomish).
When i want to make money with Eng I sell delecite arcnate converters, and gyrohoosites. I found the best money in the trade is in Fused Wireing. make up a few stacks of diffrent kinds and take them out to be killed. i can convert a few stacks of dummies to a stack of FW in a matter of an hr, durring that time i can also pull up some nice fish.
Armorsmithing is a diffrent ball o wax, since there are items that require rep you can actualy charge for crafting some items, a rule that is used by guildmembers is 10% of mat cost(capping out at 25 gold for ANY crafting, be it epic or not, 25 gold for pushing a button is on the border of insane). Sometimes costs are higher if the buyer cannot come up with some ingreadents. For example A guild crafter charges 25 gold to craft a sageblade, but if you are missing mats, and cannot get them (not in AH) he will sell you what he has at a rate higher than the AH(building in a second proffit as he likely bought the mats months ealryer.)
realisticly you cannot hope for more than a tip for any itmes that can be purchased generaly(no rep needed), or are not insane rare finds(fire protection pot for example), but for itmes that required a rep grind or farming the snot for a pattern, then you may be able to pickup some cash on the side. The real money is in the mats!!!!