It's not a stupid question, Silicone from a Hardware store is basically an adhesive, not a molding Silicone Rubber & it's much less flexible than Moldmaking Silicones available out there (Like R.T.V. Silicone).
Although I do know some artists who do mix 100% Pure Silicone from Hardware stores with Mineral Spirits to thin it down, and they use it in layers to make Silicone Dummies and for skins on prop Dummies or Puppets.