josephus wrote:any idea what type of stainless it is?
It'll probably rust in a week.
I made one like this with a cheap ss Camping plate and drilled it on my drill press, its about 5 years old now and has mashed many beers and no rust.
Should be no problem at all at the pH range it will see.
Better to have a beer that didn't turn out exactly as you planned than to have no beer at all.