Technical Tips

Proper Mixing with Dual Cartridge

Tips for achieving proper mixing when dispensing from a dual cartridge with a static mixer.

  1. Make sure there are no air pockets in either side of the dual cartridge.

Air in the cartridge will result in the two materials not mixing properly. The two sides could be off ratio and not cure to the desired properties or the mixing could be so bad as to not cure in spots leaving the surface wet or tacky.

  1. Make sure pistons on both sides are even before attaching static mixer.

It should be part of your normal procedure to place the dual cartridge in the dispensing gun and squeeze the trigger until a small amount of material comes out of both sides of the dual cartridge.  This will insure that when the static mixer is attached and you start to dispense the correct ratio of the two materials will be achieved.  This step will result in better and more consistent mixing from the very start of dispensing.

  1. Choose the proper static mixer for your epoxy.

You will choose different mixers for different epoxies based on their viscosity and thixotropy.  The best way to determine the appropriate mixer is to try static mixers with different numbers of elements, diameter and length.  You will want to check for the flow rate to make sure it dispenses in an acceptable period of time.  You will also want to dispense a bead of material and then cure the material and check for tacky or wet spots. The idea would be to optimize the flow properties while maintaining consistent mixing and curing throughout the entire dual cartridge.