Hi good morning I’m a new to the grills industry and I’ve been having an issue that’s been costing me a lot. My issue is that when I make my grills mold and I wax up using 22 gauge wax sheets and a wax pen it fits the molds perfectly comes off and everything. I take it to the castor to get casted after cast they fit the mold perfect, But sometimes when customers put them in it’s usually not fitting the teeth how I would want it to fit yet fits shorter and smaller why is that?

My hypothesis to this issue was maybe using the wax pen and keep heating the wax over and over again to get it to fit the mold perfectly before casting is damaging the wax ? Or is it the wax I’m using? Should I cut out using a wax pen all together or is the wax shrinking? If so how do o fix this issue because it’s costing me double having to make it over again sometimes.
Thank you help will be much appreciated!