Any ideas on waterproofing cardboard?

I've got huge amounts of cardboard and find it very useful for building things that won't get wet.

Now I'd like to build one of these:

https://www.amazon.com/Hungry-Bin-Flow-Through-Worm-Farm/dp/B01CRJGUOG

This is basically just a tapered box and ought to be easy enough to construct, and I can save $379 and a LOT of plastic. The thing is, plastic is kind of handy in situations where things are going to get wet, like this one.

Can anyone recommend a good way to transform cardboard to make it waterproof? I've considered:

- Gluing a thin sheet of plastic to one side.
- Painting with wax or silicone or finishing oil or some combination thereof.
- Building just with cardboard, but then stuffing a heavy duty garbage bag inside, to contain the moisture.

Anyone ever try this?

I have come across waxed cardboard, but if you are looking for eco-points am not convinced it adds much value. It's great kindling for wood stoves though.

My speculation: If you are using recovered cardboard, then perhaps using recovered plastic as well is not entirely evil, at least for experimental purposes. It depends on your personal philosophy of course.

I wonder about some of the waste fat from restaurants etc. Is there a way to paint cardboard with this and then heat it to polymerize the goo? I wonder.

Using wax on really extra heavy cardboard might work though what about the bottom of the box?

How are you going to make that part of the system work?

How does it work?

The Hungry Bin is hard on waste, easy on your back. Hungry Bin is designed to make harvesting finished worm castings quick and easy. The design separates worms from the castings before harvest. Fished castings are harvested from the bottom of the bin. No more lifting heavy and wet trays full of dirt and worms.

I didn't think about it earlier but I bet the worms would eat themselves out of house and home.

Worms eat cardboard and they might even eat wax or cooking oil.

Why not just use a plastic tub like most places sell for storage?

Or if you really want to upcycle or recycle get a 5 gallon bucket from those places that give them away.

i was just reading about some diy water proofing and there was a recipe rediscovered by  Jack Bay in the 70 s dating from the 1930 s , called Rub R Slate , it might work as it was applied to papercrete on the stuff i was reading about , have had a chance to try it out , but it looks a lot like the stuff we use to paint onto tarfelt roofs and another product which has aluminum powder bitumen mix also for painted onto tarfelt roofing

This sounds like a fantastic idea Joshua!  The cardboard is easy to replace over time and the system doesn't need to last forever. If the worms eat some of the box, all the better. A support framework could be built using wood scraps.
A similar water + cardboard + wood scraps experience that you might find interesting is that I once reinforced milk cartons with paraffin wax to make a catamaran-style row boat. Some of the milk cartons were used as is for buoyancy and some were flattened and waxed for canoe-like features. The boat held up for a couple of seasons. Really a memorable project from my childhood.
To make canning paraffin brushable and safe for worms, melt the wax in a can or pan then add a little vegetable oil to keep it from going solid too fast.

Just playing around with some garden supplies.... Driving the 3 prongs of a large tomato cage into the ground provides a foundational funnel shape. Lining the interior of the cage with flat sheets of cardboard rolled to form a cone with large upper and small lower opening, the taper shape of the vermicompost bin is easy to achieve. Layers of conical shaped cardboard hold the taper shape. A bucket at the bottom catches liquid. Above the bucket, a round sieve made with old window screening stapled to cedar bender board scraps to catch the worm castings. Untreated cardboard works easily for the lid.
As an experiment with unprotected cardboard, I fill the cone with damp leaves and kitchen scraps. I dig out the worms from a raised bed bottomless clay pot vermicompost station and top off the cone. How long will it last without wax?
I'm having so much fun with your idea Joshua. Thank you for inspiring today's permaculture experiments!