Can you make your own rubber boots?

Dear users, dear authors,
a quick question as the workday winds down: Has anyone ever tried making their own rubber boots or waterproof overshoes (possibly foldable ones)? If so, how do you sew them, and how do you make them waterproof?

You could make something like that out of oilcloth, rain jacket fabric, or waterproof canvas.
Water sports stores (and surely “regular” sewing supply stores as well) carry special thread that “swells” when wet and seals the seams.
Alternatively, you can also stick waterproof seam tape (I’m sure there’s a proper name for this 😂) over the seams.

The things people come up with :-)

I’m surprised.

I’ve often thought about making cushions for the garden. It rains so much where we live, and if you could make the covers waterproof, you could leave them outside. 

Petra, yes, that works.
These “pallet cushions” are usually made from that kind of sailcloth too (not the simple canvas you get for sewing clothes or bags) and sewn with water-swellable thread.

Thanks for the tip. I’ll look into it online. I’d also like to stop by the fabric store today. Let’s see if the saleswoman can help me out, too. 

There are also waterproofing detergents and sprays, but I’d generally lean toward outdoor fabrics.