Is there a specific bonus to weapons created using alloys created with someone that has three dots in alchemy path? One of my players asked a blacksmith to make a sword out of alloys he made and I'm not sure about the exact bonus the alloy bestows.
In my games, whenever someone wanted Matter based weapons I usually go with the path of artifacts, as described in the storyteller's companion book (chapter 4). Creating an artifact that gives some permanent bonus (with matter 3 I will usually go with -1 difficulty to hit and/or +1 damage). The effect requires Tass of the appropriate resonance (Prime 3) or any Quintessence (Prime 4) plus the spheres required for the enchantment (in our case, Matter 3, although I always find useful Prime 2 for aggravated damage).
The number of success needed is twice the value in points of the artifact, its calculated as the sphere effect (times 2 if it is permanent). So in our case 3 times 2, 6, times 2 again, 12 success needed (probably in a ritual!). The amount of Tass needed, as with other Wonders is two times the value of the Artifact (so, 6 times2, 12).
Remember that permanent effects end up having some kind of resonance themselves, and if your Willworker ends up sleeping in their protected bad-ass long coat, then they should also gain some resonance.