There is nothing more frustrating than a stuck bolt that won't come lose. This is especially true if you are half way through a project when you discover the problem bolt. In order to finish your project consider taking advantage of these tips to loosen up the bolt.
Several things can cause a bolt to become stuck in place including both rust and corrosion. In order to break the seal that has formed between the bolt and screw it is useful to apply a penetrating oil over the entire area of the bolt. A trip to your local hardware store will produce several products that can be used for this task. PB Blaster is one of the most popular, although Liquid Wrench makes a similar product. If you can't find anything else WD-40 can also be used.
In order to get the best results you may need to let the penetrating oil soak for several hours. If you still can't remove the stuck bolt apply another liberal coating of the penetrating oil and let it sit for several more hours. Before each coating of oil use a hammer to gently strike the bolt a few times in order to eliminate as much rust and corrosion as possible.
Tip: Stuck bolts require extra finesse when you attempt to remove them. Consider using a socket wrench to get a good grip on the bolt. If you can put a handle extender on your wrench it will provide you with additional leverage. You want to avoid stripping down the sides of the bolt during this process as this will only make your job more difficult.
If several attempts with the penetrating oil has failed to remove your stuck bolt there are still alternatives you can try. Many people rely on small propane blow torches to accomplish this task. Use the blow torch to heat the bolt for approximately 30 seconds. The heat will actually cause the bolt to expand. You may need to let the bolt cool and reheat it multiple times before it finally comes free.
Tip: Make sure to use a clean rag to remove as much of the penetrating oil as you can before you try the blow torch method. Always use caution with the blow torch and make sure there is nothing flammable in the immediate vicinity.
If all else fails, consider using a hack saw to cut the bolt off. Depending on where the bolt is located you may be able to slip the blade of a hacksaw directly above it in order to cut through the screw. This is only a viable option if the screw is replaceable.