You’d do much better pleating the filter media then gluing the edges all around the jello cup. Pleating gives you more surface area. This has much less breathing resistance and higher filtration efficiency.
Last February when this first came out and not much was known about it, I printed masks for my wife and I on my 3D printer when it was unknown just how deadly it was and they had reports of people dropping in the streets in China. They made it sound like the Black Death, so I prepared in case we needed that.
There is a cartridge on the front that I can remove...I purchased some standard 3M Filtrete furnace filters that can filter down to particulate level (but cannot filter out viruses not borne by particles) and took them apart, cut them to size to fit in the filter held in place with rubber gaskets on four sides with screws inside a plastic holder frame.
All in all, it was a pretty good mask, but...I never wore the thing, because by the time I had it printed and set up, it was clear that the virus was not the killer they made it out to be.
If it had even a 5-10% mortality rate, I might have worn it, but the mortality rate was down in the flu range just a little more, so I didn’t wear it.
But it gave me practice in printing it.