In most cases, a 250ml adhesive cartridge will produce a 40 ft ¼” bead. As each project has different needs, you need to calculate your own specific needs. Generally, if you are close to needing an additional cartridge, you should order an extra cartridge. Several Mixing Tips per cartridge are usually necessary. Each time the adhesive gun is set aside for more than 15 minutes, the glue in the tip will harden; this necessitates installing a new tip prior to reuse.