Made it out of 18mm softwood ply in the core with 9mm hardwood glued on each side to make 36mm. Hidden hinges in the centre and magnets to pull it together.
Hopefully the ply won’t warp over time. I didn’t think I could make it strong enough around the bifold any other way. It’ll probably need a 3rd hinge in the middle but they were £35 for a pack of 2!
Ebay is your friend here for a single hinge, just make sure its identical.
Fitting is a breeze too, as the weight and orientation is already dealt with by the upper and lower, the third will just pop in and not effect it any, just add strength.
A wee suggestion though. Where they meet in the middle on the outside. No need to try to get it to look flat and a single unit, a small chamfer along those leading edges helps hide the join by emphasizing it, but it also means when you paint it,theres less chance the paint with try to flake or chip off as paining sharp edges never really ends well.
I would even go so far as to run a small face moulding down them to compliment the moulding on the panels, again the trick is not to try to hide its two doors by trying to make it look like a single door.
And overall you’ve done really well and it looks fantastic.
The view out the door looks really good too with the tiled floor. I dont know how folk manage to do it. I mean Ive a nice tartan carpet, and original stripped doors, but when you look out into my hall,instead of it looking good like yours with the cool flooring, the matching sideboard and modern lighting, mine is a bike, a wheel or tyre or two, a morticing machine 😆
And don’t worry about warping, its not really anywhere damp. Plus all the hinges will hold it tight to shape.