One can be bought from Knick Knack in Little Lamplight. Dashwood's safe, in Tenpenny Tower, received for completing A Manhandled Manservant. Jocko's Pop & Gas Stop, northwest of Tenpenny Tower and east of Girdershade.
A quest reward from Moira in Megaton after the Minefield portion of the Wasteland Survival Guide quest. If you are having trouble locating the materiaals, you could use as an aid. Hidden inside the Yoo Guai Cave, at cliffside caverns Craterside Supplies, sold by Moira Brown Mother's favorite Bible verse plaque in your fathers lab. The Wasteland Survival Guide, awarded by Moira Brown. Tenpenny Tower, Sold by Lydia Montenegro
Here is a list of the ingredients needed and the location to find the plans The weapons are Shishkebab, Bottlecap Mine, Dart Gun, Nuka-Grenade, Railway Rifle, Rock-it Launcher and Deathclaw Gauntlet. For this, you have to create one of each of the custom weapons on a workbench.
