Spring Hardening

If you want to increase the power of your gun, the usual thing to do is to by a new stronger spring. But there's a cheaper, way... Hardening the spring by tempering. But before you start there’s some stuff to think about! When doing this mod the results depend on allot of different factors, so getting a consistent result is near impossible. And remember all mods risk breaking your gun!

The principle
When you compress a spring the metal wants to retain the original shape. That's the reason it gives a force. The harder the metal is the more force is required to compress the spring. So when a company makes a spring it 'set' the hardness to match a specific spring stiffness (The M rating e.g. M100 for a spring that will give 100 mps). The way they control the stiffness is called tempering. (Because it's controlled with temperature). And in the same way you can change what the factory did to the metal.

When you heat up metal it softens. And when it reaches a specific temperature it's structure changes. After this point the metal's cooling process determines the hardness of the metal. So heating the metal and re cooling it changes the stiffness... And that's the process we can use to increase spring stiffness in the gun. Here you see a un modified spring, note the compression is even.

Step 1
Heating the metal to critical temperature. To do this step you must heat a part of the spring. The bigger part you heat the more stiffness. So if you heat a big peace you will increase the power allot, and if you heat a small part you get less power. But be aware that the bigger part you heat the more prone to breaking will the spring bee. So in general it's better to heat 2 small parts than one big part.

Step 2
Cooling the spring. When you have heated the spring to near red hot, the rate of cooling will determine the hardness. Rapid cooling gives stiff springs. So we are looking for rapid cooling... I use cold water (remember safety because of hot metal hitting cold water gives strong reactions). A big glass of cold water, and dumping the spring in it have given me god results.

Make sure that the spring compresses in an even way, without bunging put to one side. Or else the spring may damage the insides of the gun when compressing. Also make sure the spring itself is straight. After the hardening process doo some compression cycles by hand to make sure it seems good and hard enough. Here you can see a modified spring, note that in the middle there's allot less compression because of hardening.