Solid Surface glue guns are not all created equal.
There are a couple of recommendations to keep in mind when using 10 to 1 dual component glues for fabricating solid surface and stone products like Corian, Cambria, Silestone and HiMacs.
One common misconception regarding 10 to 1 solid surface adhesive dispensers is that they all provide identical performance. Based on our experience and extensive testing, we know that there are marked differences in cure consistency. Specifically, the lower cost metal dispensers tend to have a high mechanical advantage which can lead to off ratio mixing if the user pulls too hard on the trigger.
The excessive pressure on the cartridge may cause the cartridge to bulge slightly. When the cartridge returns to its original size after the trigger is released, the glue component (large side) will continue to flow out of the cartridge while the activator component (small side) will not. This problem results in an area of the bead where the 10 to 1 ratio is off and the glue bead will have “hot” and “cold” spots in the cure. (Another reason for hot and cold spots in the cure is air trapped in the cartridge. Refer to the post “How to properly purge a cartridge…” for more info)
To test the dispenser you have, simply take a cartridge of light colored solid surface glue, purge as always, and lay out a bead of 6 feet or so on wax paper pulling as hard as you can on the trigger and pausing between strokes. Every time you re-trigger, deviate from the bead a little as a mark for later. Continue to crank on the trigger and run out about a third of the cartridge. Make sure to continue to pull hard on the trigger.
Observe carefully the differences in the curing material along the length of the bead. Notice how there will be sections of bead that cure significantly slower than other others. If you have used a light color, you may also see areas of discoloration due to “hot spots.” These “hot spots” cure faster because there is the same ratio fluctuation. In extreme circumstances, the bead may not cure at all in small sections or the discoloration will ruin the appearance of the seam.
To solve cure issues, the answer lies in both the operator and dispenser. If you want to use an economy model for cost savings, be sure to apply even pressure on the trigger to minimize ratio fluctuation. The best option is to purchase a higher quality tool that is designed to limit the adhesive output and provide an even cure.