How to unscrew the bolted bolt and leave it whole

Every time, when approaching to any mechanism that has long been demanding inspection and maintenance, the owner is uncomfortably scratching the back of his head. Outside, the mechanism, as a rule, is already fairly spoiled with rust, and for sure all the connections are tightly picked up. And so every time before unscrewing the bolted bolt. The whole hunt for work can be repelled!
And what happened is this. When the bolt was tightened, the necessary tightness was not achieved, moisture entered the threaded connection , and the reaction of water with iron in the presence of oxygen gave hydrated ferric hydroxide, that is, rust. She scored a carving, the junction jammed. Well, how to unscrew the bolted bolt, if the connection is not spun for years?

To begin with, you can try to dissolve rust. This is well done by glycol - a substance contained in antifreeze or brake fluid. A damp cloth is placed on the stuck carving, the glycol will penetrate into the rust, loosen it, and unscrew the rusted screw will immediately become easier.
In kerosene thread well penetrates kerosene, and even a solvent of white spirit. Therefore, craftsmen from car repair shops in difficult situations like to use WD-40 aerosol, half-composed of white spirit. In order for the liquid to penetrate the thread better, you can tap it lightly over the head of the bolt. Wait for no more than 10 minutes.

And still there is, so to speak, a scientific way, how to unscrew the bolted bolt. Around the head of the bolt it is necessary to build a rim of plasticine or wax, put a little zinc inside and pour sulfuric acid. She will not have time to fasten the fasteners, because she immediately pounce on the rust and, reacting with zinc, will start on the surface to restore the iron. The chemical reaction will literally clean out the rust from the thread.
If it does not work out, you can resort to heating the bolt, then you need a gas burner (or a soldering iron). The bolt heated to approximately 230 degrees should cool down. In the process of heating / cooling, the changed geometry of the metal will destroy the rust so that the threads are released to penetrate the liquid lubricants. And then there are no problems with how to unscrew the bolt, should not be.

When unscrewing, there should be a quality, reliable and tested tool in your hand. Of course, not made in China. The carbide keys are ineffective in such a case - get the crushed heads of the bolts and the downed hands from the disruptions. Use nakidnymi keys and heads. Unscrew the movements back and forth, spinner, as if you are cutting a thread or pulling a jammed car out of the mud. In this case, penetration into the thread of the lubricant will increase.

There are also more radical and extreme ways to unscrew the bolted bolt. First, tap the head of the bolt from above with a hammer - this will break the structure of the rust. Then, using a chisel or a strong screwdriver and a hammer, tap all the edges of the head alternately, directing the shocks along the axis of rotation. In the vast majority of cases, the stubborn bolt must succumb and twist.

And the last. When you re-tighten the bolt, please do not forget about graphite grease, solid oil or engine oil. Then for a long time, no corrosion, no oxides will be scary for a long time.