Vacuum Grease Application Guide

Your Guide to Greasing Vacuum Joints Effectively With Vacuum Grease

Do you know how to properly grease a joint for vacuum applications?

This deceptively simple practice has been the cause of much frustration in commercial laboratories. Who would have guessed that something as simple as using vacuum grease to grease your joints properly could prevent glass breakage, lead to more effective products, and so greatly impact the efficiency and effectiveness of your lab?

Now you can avoid leaky joints, stuck glassware, and the many problems that can occur as a result of these simple issues.

This guide will show you once and for all how to best grease your vacuum joints – whether using Krytox, Dow Corning or similar – so you’ll never have problems again!

How To Grease Vacuum Joints

1. Use a Pea-sized Dab of Grease Many individuals do not know, and this is one of the main problems that can cause a leak when performing vacuum distillation. When properly greasing a male joint, one should use about a pea-sized dab of grease. Proper portioning is very important – too much grease may result in contamination, while too little can result in vacuum leaks.
2. Evenly Spread the Grease Spread grease from the narrow end of the male joint upwards, in thin sufficient stripes about ¾s the total length. Leave extra room at the bottom (narrow) portion of the joint ungreased to minimize grease contamination as well as allowing for grease penetration. Too much grease can cause channeling, which leads to leaks. You should create three to four of these “stripes” equally around the male joint.
3. Gently Insert the Glassware Once the stripes of grease are made on the male joint, insert it into the female portion of the joint.
4. Twist the Joint Back and Forth- Carefully Twist the join back and forth. You should hear glass scratching sounds initially. Keep twisting back and forth until the scratching sound goes away and there is a smooth, clear band across the whole joint. It should feel very smooth when rotated.
5. Check your work! Once you see this smooth clear band and hear no scratching you should have a sufficiently sealed and greased joint.

Vacuum Joint FAQ

My glassware is stuck to another piece of glassware. How can I separate the two?

Glassware getting stuck together can cause various issues, including glass breakage. To remove one piece of glass from another, care should be taken! A heat gun is the first suggestion for getting two pieces unstuck. Turn on the heat gun and heat the outer joint for 10-15 second increments. This heat should allow the outer joint to expand while the inner joint stays the same size. If done correctly, you should be able to pull the two pieces apart. If the problem persists, a blowtorch may be used. Heat the outer joint for around 5 seconds, and then try to separate the glassware. People performing these methods must take extra precaution not to burn themselves from the torch or by touching the hot glass after it’s heated!

Ready to get to work? Purchase vacuum grease here.