It's a grind

So I'm grinding someone else's glass, so it has to be perfect.
It's a curved surface, and it's black, which shows imperfections oh so we'll
I thought I got to the Polish, but it turns out there are several areas that either need more cerium/ felt love, or maybe have to go back a step.
I've been using silver sharpy to mark these areas.

My question is, is there anything I can use to mark trouble spots that won't wash away as easy? Maybe something that only comes off with soap or alcohol?

It'd be a time saver not to have to think I'm done, rinse the glass, dry the glass, and search all over again looking for those spots to see if I got'm; find'm and re-mark, repeat, rinse, etc.

[Pete VanderLaan]

If it's an inside curve, it will never look perfect no matter what.
I use black sharpies but allow the ink to dry first. We use a boatload of paper towels to inspect. Stay on the wheel about five times longer than you think you need. If you are using small tools, 15 times longer.

Glass is not glass. Polishing really varies from type to type.

[Jim Bowman]

I mark the area I am going to coldwork with a sharpie, and then put a little chapstick over the marks to repel water.

I'm gonna remember that one.

[Eben Horton]

I use a wax pencil

[Peter Bowles]

It sounds obvious, but took me a while to get to, was to mark the perimeter of the area to work on, not directly the area itself.

[Greg Vriethoff]

Originally Posted by Jim Bowman

I mark the area I am going to coldwork with a sharpie, and then put a little chapstick over the marks to repel water.

Originally Posted by Eben Horton

I use a wax pencil

I had never considered waxy substances to repel water. Thanks for sharing.

I know we're talking really small amounts, but I like to overthink things. The question I have is wouldn't this clog belts/disks/wheels/whatever over time?

[Eben Horton]

Nope........

Someone I knew called wax pencils "Chinese Sharpies"

[Eben Horton]

I Also use them to mark the inside of a pitcher so I know where to land the handle and where to attach the tip Of it. Works like a charm and wipes off the next morning

[Pete VanderLaan]

the smaller you make the objective point, the greater the chance that it will show as a polished point. It really is the way the world goes round. Optical Gods do get angry.

[Greg Vriethoff]

Originally Posted by Dan Vanantwerp

Someone I knew called wax pencils "Chinese Sharpies"

They are known as China markers.

[Greg Vriethoff]

Originally Posted by Eben Horton

Nope........

Thanks, Eben. I worry about too much stuff that I shouldn't.