Got a table leg, a swing set or just about any other item with chronically loose nuts and bolts? Here's a quick fix to keep metal threads tight once and for all (not for plastics) using color-coded Loctite Threadblocker products.
Loctite Threadblocker Blue 242 (at home centers) is great for locking together 1/4-in.- to 3/4-in.-diameter fasteners. Blue creates a strong hold but can be broken free to unscrew the fastener when necessary. Red Loctite 271 is for larger fasteners and more permanent connections for swing sets, decks and ready-to-assemble furniture.
With either color, you just squeeze a little Loctite adhesive onto the threads and then tighten the fastener. The bond will set in 20 minutes and cure completely in 24 hours. The Loctite adhesive prevents fasteners from vibrating loose or rusting. It also does a good job of sealing metal plugs in water or air tanks.