Silicone lubricant prevents cuts and allows the aluminum couplers to slide in further than brute strength. I get some stuff called pool lube at a pool supply website (Leslies). I work at a place that manufactures lots of high and low pressure ducting for aircraft, so we are familiar with this type of stuff. This is why I purchased Murray constant tension clamps. The OEM clamps are good, but there is nothing to prevent them from loosening. I have a list of sizes and what they look like in my build thread. I installed my FMIC several weeks ago with no loosening of any clamps. These clamps are $6.00 to $9.00 but are worth it. I got most of them at McKenney.com