Sewing

I don't have much experience with sewing or machine-compatible fabrics, but have you considered waxing normal cotton? I put a few coats of Sno-Seal on my jacket at the start of every winter and it does a good job of waterproofing and adds another layer of insulation

Depending what you're doing and for how long, many thick materials will keep you dry without being actually waterproof. Most of them will require deliberate drying if they're fully soaked, and of course an outer layer with the capacity to shed some water will multiply the time the inner layer can keep you dry for.

For regular walking around, it's worth trying some cloak materials you're using anyways to see how well they handle water.

@sewing@lemmy.world @sewing@a.gup.pe @Shkshkshk I made a full-circle cloak of 24-ounce-per-yard navy blue wool that I washed and dried before cutting. It sheds rain and snow quite well. After about a decade of regular use in all conditions and locations, it’s still going strong. The cost, of course, is the weight, but the wearer loves it. It’s not about the right product; it’s about the right product for you.

When I google "waterproof fabric," there are a lot of canvas materials and some polyester ones that come up. Waterproof canvas would be good, but good have to make sure the machine can handle heavy materials - some can, some can't.

If cost isn't a problem there's ventile/etaproof. 100% cotton and can withstand rain for 2 hours. Add a second inner layer and it's even longer