Not all cardboard it created equally, a fact I think I found out entirely by accident.
My craft experience recently has largely been fabric based. I know what I know from a lot of trial and experience, and while that happened with these trees, it was in the minutia of the design process, not the materials. I got lucky. Having decided that this was going to be this years project of evil* I headed down to Officeworks to see how much it would be for some nice cardboard. Had I still been working at a supermarket I would have just grabbed some old boxes and been done with it, but the boxes are a lot smaller at Dan Murphy's. This turned out to be for the best, because the lady I asked must have misinterpreted my request for "some thicker cardboard, like, sheets of corrugated, to use for craft" to mean specifically the thicker double corrugated stuff.
See, most corrugated cardboard is made up of 3 pieces, the two edges and the wavy bit between them. But there also exists double corrugated cardboard, which has a flat middle with two corrugated bits either side, then the flat edge bits again. The lady at Officeworks came back a couple of minutes later with a few boxes made of this stuff that she'd taken out of the rubbish for me and asked if they'd be okay. Without this nice lady, the whole thing might have failed.
See, when you bend corrugated cardboard along the waves, it loses that gap and therefore a lot of it's strength. Its those gaps that make the whole thing work. And with double corrugated stuff, you still have one layer of gaps intact when you bend it nicely, so you get a nice shape and still keep it strong enough to hold 9ish kilograms of beer, plus all the glass its in.
The next time I went into Officeworks I found out that they actually sell moving boxes made of the double corrugated stuff, but I think it'd be about $20 to get enough cardboard. Fortunately another staff member got me more for free, which was lovely of him.
The last lot I got from Big W, entirely accidentally. I thought I was done after the third one, but there was a trolley of the stuff just sitting there, like it was waiting for me. I know a sign when I see one.
When I went home for a few days last week dad and I debated the possibility of making one entirely from PVC plumbing pipe, like I have as the centre tube in my tree, but it'd be so much harder to cut in the curves. The cardboard ones may take 10 hours a piece and about 2 rolls of sticky tape each, but they will have to do for this year.
*My mother says any time that dad or I come up with some outlandish/random/cool af project "why can't you ever use your powers for good" so by extension, everything cool we do is a project for evil. This was one of the fist things she ever conceded was actually cool af.