In case rising pressure as the gas heats up is a possible problem, might be worth leaving a gas ring on low while doing it.Ive always protected so the gas pipe don't even get warm. Not difficult to do that.
I've seen plumbers just get in with it. I guess the thinking is heat won't do anything unless gas is leaking out pipe just where you have the flame.
Great idea , I've got plenty of ceramic tiles laying around, I'll put them to use. I will also wrap the gas pipe in a cold wet rag.I've shoved an old ceramic tile then soldering matt over that in the way of gas pipe to protect.
Can you not make up that section int advance then join away from gas pipe?
If the tile is not evenly heated it might shatter.I've got plenty of ceramic tiles laying around,
Get someone else to do it while u hide in garden!