coffee filter retainer

[Frank S]

The idea is sound enough and works fine the ring will hold the filter edges in place long enough to prevent the grounds from flowing over the sides but the rings will not take the heat. Making them a consumable. The diameter of the 2 ltr. soft drink bottles is perfect for my coffee maker so Eventually I will drag out a piece of 304 ss tubing that I have slice it open flatten it out and thin it down then roll it into a ring the springiness will allow for compressing slightly for insertion into the coffee maker.
most grades of SS is or can be rated food grade, and 304 or 18/18 is among the most popular for utensils or pots and pans.