You need basic tools for carpentry and wood working, manual or powertools. This bed can be made using only a saw, a screw driver and a steady hand for straight cutting..... Im a bit on the lazy side so I used a jigsaw and a drill (a battery screw driver could work as well), you also need 3/4" or 1" x 6" x 10' boards and a pole 6" diameter. (How many boards you need or how long the pole, depends on how tall you want your bed to be. (standard height of a bed is about 2 feet) and the size of your mattress so you will have to do those calculations yourself...... lazy side remember).
1" board will make a stronger more sturdy bed so I recomend those. You will also need about 20 screws, and 3 or 4 hours of your time.
To make the fire finish you will also need a plumber's torch or any other gas torch but of course this is optional.
ONE MORE THING... REMEMBER TO TAKE ALL SAFETY PRECAUTIONS DURING WOOD WORKING
I'm in the middle of making it, and do have one major thing to note for anyone else making one.
Do not use un-reinforced cedar for the main planks, and do not use a corner post that is too small.
I'll explain.
When you cut the planks off right after the main joints to make them sit flush, you're left with an approx. 1" piece of wood sticking up, with nothing to prevent it from easily breaking off. This leaves a weak piece, and potentially a very weak joint. Allowing the board to protrude from the post, or using a thicker post, allows more wood to remain to reinforce that piece. The reason I advised against cedar is because it splits too easily... I've already had three of these pieces break off!!
If the fix described above doesn't work too well (i.e. you either have space limitations, or you've already cut them, both of which describe me) I've got another one. Buy some small metal sheets, less than the thickness and width of the board, and screw/glue them on the ends. If they're made of brass or another nice-looking material, they will still look nice and hold up. For further reinforcement, you can drill holes in the posts and reinforce with bolts that can be removed to take the bed apart.
Unfortunately, this might ruin the aesthetic of the bed; just shop around to get something that can fit your tastes. It's either find something that works, or start again from scratch!!
Here's a traditional Japanese finish called Shou-sugi-ban. It entails charring a type of cedar, washing and then applying an oil finish.
materiadesigns.wordpress.com/2009/12/27/shou-sugi-ban-terunobu-fujimori-charred-cedar-siding/
pursuingwabi.com/2007/11/05/shou-sugi-ban/
remodelista.com/posts/outdoors-shou-sugi-ban-wood-siding
lumberjocks.com/projects/23574
I used your guide, but with a few minor alterations, to make a king sized version of your bed. I used larger boards for the sides and also used three 4cm x 4cm beams to support the planks - gotta be strong enough to hold two people. The mattress I have is a Tempur one that measures 1.5 metres, by 2 metres. I've got a little more work to do on it like trim the ends of the main boards so they are flush agains the legs, then apply some sort of finish (my gf probably won't like the pyro idea though).
Thanks for the guide, I had a lot of fun building my own bed =)
Probably a carpenter reading this could give a better advice?
Disclaimer: I'm not a professional carpenter, either, but I have done quite a bit of carpentry and woodworking, from barn lofts to finish work.
Bunk beds shouldn't be much of a problem if you keep everything nice and tight, but a loft with no lower level would be harder to stabilize. You'd definitely have to use slats on the end for bracing, like a standard headboard & footboard on a bunk bed. A loft would need at least one slat or some sort of bracing long-ways so it doesn't want to fold up.
(Also - six inch posts would probably still be adequate. Cutting two perpendicular 1.5" slots still leaves you with the approximate equivalent of a 4x4 post.)
For the lower bunk frame, the frame would slot in pretty much the same as the instructable. The only difference would be that you'd have to put the slots right through the post instead of just in the top. One of the slots would be 1.5x as tall as the slat board to allow it to slide in and drop over the other. (Doing this on the top as well would provide more structural integrity.)
End slats would probably need some sort of peg to secure the slats into the slot in the post. Also make sure kids know "if you pull this out, it falls on your head". Could save more than one kind of headache.
Darn, now I want one. Need to go sketch this whole thing up...