material for making patterns

How much water is your grinder slinging around? You don't need to flood the glass.

There is a product called "Mark-Stay", comes in a little screw-top bottle. It's the consistency of axle grease, and pretty waxy. It will protect your Sharpie marks.....or, you can just use plain old Vaseline over the marks. But you'll have to wash the glass very well or the foil won't stick.

You also could use paint pens...gold and silver work good and seem to be more water proof than markers.

Best advice? cut the glass closer to finished pattern size, and knock off all the grinding. You should only have to use the grinder to put a matte finish on the edge of the piece so the foil sticks, not grind the piece to finish fit size. Practice on the cutting......

You're spending way too much time at your grinder. You need to learn to cut accurately the first time, and just grind to take the sharpness off the edges so the foil will stick. I use a light table and sharpies, and have no trouble with the mark washing off.