How do you make things airtight?

Answer 1

The best way to make an airtight bag is to use one of those fancy bags that you suck the air out of. If you are looking for a cheaper way then plastic bags (garbage bags) will work. You just make an incision and suck the air out and close it before the air comes back in. One can make airtight bags using existing plastic bags and a lighter, soldering iron, or another device capable of melting the plastic. For small airtight bags, one can start with a plastic sandwich bag where three of the sides are already made and generally already airtight. In order to seal the open side, one can lay a flat, metal object (or another material that won't burn, this is the guide) along the area one wishes to seal and run a soldering iron (or any metal utensil heated enough to melt the bag) along the outside of the guide. The two pieces of the bag should melt and fuse into an airtight seal if done carefully. This technique can be scaled up using garbage bags or larger pieces of plastic to create larger bags.