How I build my pinhole cameras
Materials:
Xyltech: I live in France and I don't know if it's available in other countries. I suspect you'll find the same material with or without the same name. This material is insensitive to water, cheap, eco-compatible. I use 5 mm thickness plates, it can be cut with a good cutter and easily glued. It acts like wood. These pieces of Xyltech are the wholeness of my pinholes except external angles and pinhole hole, if it makes sense. Xyltech's pinhole camera is about two times less expensive than the same made using foam cardboard but it's way more robust. My first tests were in foam and cans. Since I found Xyltech I keep it to build my cameras, I only find advantages. Here in France it's available in almost all handiwork shops, even in my remote countryside.
Brass plate 50 microns (about 0.002 inch): One of the first questions we ask when beginning pinhole cameras making is what kind of material to use for the pinhole. It must be as thin as possible and totally opaque in the same time. First I used beverage can pieces but it's far from ideal, too thick to be the best but it works. I also used aluminum foil found on top of soluble coffee cans. It works well too. But what is used by professional pinhole builders? 50 microns brass. Some even use 20 microns foil. Laser perforated pinholes generally use 50 microns so I used "mama zone" and bought some. It's cheap, easy to cut, easy to drill and eventually it's easy to get a perfect pinhole perfectly rounded without burr, perfect to take photos.
Gaffer: A kind of adhesive canvas witch can be removed and replaced without traces. It must be opaque. It's the theory... Here in France it's easy to find adhesive tape named gaffer but most of the time it's not opaque, not durable, not really real gaffer. Here the best way to get it is to buy it in a specialized photo shop. It's a bit more expensive but not outrageously. Don't forget you'll use at most 2 meters long per camera so that's not the most expensive hobby you can practice. A good gaffer will last many years. I use 50 mm large and find it invaluable to fix the brass pinhole and remove light leaks if any.
Corner angles and sticks of wood: Corner angles will reinforce the solidity of your camera and reinforce their light proofing. Same for inside sticks of wood.
Matte black paint: Essential. All parts inside of pinhole camera is painted matte black. This way it blocks all reflections of light, avoiding disturbing traces on your photos, the famous light leaks. Without this matte paint, even the weak light passing by the pinhole can bounce on inside walls and kill your photos. Bomb or brush, you chose, both work.
Tools:
A good cutter: Essential tool to make a pinhole camera. Avoid light cutter, it's perfect for paper ou cardboard but not enough strong for Xyltech or plywood. Your hands deserve more, take care of them...
Sanding paper 800 grit: You'll need it for a perfect pinhole, perfectly round without burrs or splinters. Generally available in car repair shop.
Clamps and perhaps frame press: Glue takes time to dry, these tools will be a precious help. Frame press is an accelerator to glue boxes, with it you're sure frame is right without keeping handling by hand. Drying is what takes the longest, way more than cutting and gluing. It's about the same drying time for a 12x18 cm or for a larger 24x30 cm pinhole camera.