Sealant cartridge holder

I made this design quickly, it's not perfect, but it did help me get out of a bit of a muddle in the workshop. 

I am providing the step so you are welcome to remix. Some advice:

• Use good PETG or stronger, I used some old stock and new, new stock worked great, old stock split at the screw holes (4mm wood screw)
• Don't use a high torque setting on the drill
• If you also have trouble with splitting in the corners, thicken the wall up a bit.