Which Packing Cup is best?

When using an Albion caulk gun for bulk caulking or chinking application, leather is a one-type-fits-all material for packing cups and is included with the gun. The packing cups are the plunger-type component that pulls the sealant into the barrel of the gun and pushes it back out. In some situations one may choose to replace the leather packing cups with a different type of material. Here is a general guide for when to use which cup:

#21-1 Leather:  Low friction, tough and durable, excellent chemical resistance.  Soak in motor oil to maintain.  May swell then break down when used with water based materials.  Oil more frequently or choose another packing cup for acrylics. 

#21-7 Impregnated Leather:  Similar to soft leather cups but stiffened with wax to reduce water absorption and blow-by.

#21-16 Nitrile Rubber:  Good seal, elastic, moderate friction.  Excellent for water-based materials.  Preferred by chinkers.  Not recommended for use with solvent-based materials.       

#21-26 Nylon:  (Not shown in image) Springy, moderate friction.  Better chemical resistance than Hytrel.

#21-24 Teflon:   Very low friction, excellent chemical resistance.  Be careful not to nick or bend out of shape.  Expensive.  Excellent for bulk or sausage packes.

#21-24 Hytrel:  (Stiff "H") Higher friction, good chemical resistance.  Sharp edge makes it excellent for sausages.