One of the biggest mistakes that you regularly see in spring-powered guns brought in for a service is inappropriate lubrication. Some guns are full of grease, some are dry, and some are just full of the wrong products. Here is a guide about what to use and where:
Which lube should I use?
Molybdenum-based lubricants are by far the most common and easy to buy for airgun use. From standard moly like Abbey LT2, through high-moly content pastes such as TbT Bum-Slide to dry-moly powders, which can be burnished into a metal surface, there is a formula for everyone.
Never use silicon-based lubricants, as they are not suitable for metal-to-metal applications!
Oils have no place inside a spring-powered airgun, but a good-quality gun oil should be used to keep the metalwork in tip-top condition.
Where should I put it?
For our customer guns we use a standard moly on the springs, plus Bum-Slide on the outside of the piston, on the rear edge of the piston seal, and on all other metal-to-metal contact areas.
How much should I use?
For the spring you want a pea-sized blob, around the size of a thumbnail, in the palm of one hand. Then slowly pull the spring through it and work it in so it has a very thin layer all over, finally pulling the spring through while gripping tightly so most of the grease is left on your hand. That is plenty! A lightly lubricated spring with correct-fitting guides negate the need for a piston sleeve in most cases, saving you time, moving weight and potential future wear problems.
Everywhere else we use Bum-Slide in tiny amounts. If you have polished your piston so it’s a nice shiny finish, a small amount on the tip of a finger can be worked into the surface until it turns a dull grey. For the rear of the piston seal, I usually use the remnants on my fingertip from lubing the piston. Likewise with other metal-to-metal areas, a tiny amount is all that’s needed.
Any finishing touches?
All your efforts at lubricating your springer will come to naught if you don’t degrease the inside of your compression tube. When you push the piston back in, the seal will scrape all the old grease off the walls and take it down to the end, where it will diesel away for ages. Always clean, degrease and dry thoroughly before rebuilding.