After all, their basic, framed assembly secures a caulk tube, while a drive rod with a plunger pushes the tube's internal piston forward. In this DIY setup, the clamp essentially becomes the new caulk gun frame, as this type comes with a drive rod and a trigger, which will allow you to ratchet the caulk tube forward, similar to the action of a caulk gun. The tape will hold the caulk tube in place, preventing it from falling out during use, and the wood acts as a plunger into the caulk itself. For the wood piece, you'll need a thin slice, cut to fit the caulk tube. If you don't have an electric saw, you can go to a hardware store and have them cut the wood piece for you for free.