This instructable involves ironing, cutting etc. suffice it to say, there are many points at which you can hurt yourself. So please be careful.
You don't have to use the same materials but I used many of these as they were leftovers from other projects.
Step 1: Supplies
A cutting board - I got this one from Ikea on sale, but you can use any flat surface that will be the top of your desk. One thing to keep in mind you want it to be hard and heat resistant (those laptops get molten hot). Finally in my case it was the color that I wanted the top to be, so i didn't need to paint anything.
Some fabric - this one looked fun so I took a 1/2 yard to be safe.
Liquid nail to do the final glueing. if you don't want to drill and have screws on the surface, but this can be bypassed.
Some scrap wood- this can be multiple pieces or a panel, use what you have.
Filling like pillow stuffing, foam or polyfill.
Some screws - I used drywall screws.
Step 2: Measure and plan
Next you want to plan on how deep (high) your pillow will e. to mine I added 3 inches to each side. I did it so high because i wanted to have stuffing between the top panel and my legs when the weight of the laptop was on top of the desk. Think 3d and you should be able to get this step done with not too many issues.
When you have that done, set it aside.
Step 3: The core
In my case I took three similar pieces and screwed them together. then I cut off the tips of the screws that pointed out of the top.
It's important that you have a flat surface, as this is where the desk attaches to so you might want to do this step on a hard surface. If you have a nice panel of wood to work with then just cut it to size and you should be good.
Step 4: Empty pilow
First plan on cutting the outer most perimeter that you drew on step 2. Before you do that though, plan on leaving some extra on the side of each edge ~1 in so you don't have to be precise.
****This additional fabric we will used to staple the pillow to the core. If you cut it to the exact measurements from step 2 your pillow will be too shallow. ****
So just leave some extra to each side.
Then fold it to look like a box. This is somewhat difficult at first but if use an iron to crease the length and width of the "pillow" you will see that it sort of comes together. This can be a lot like wrapping a box in wrapping paper, but there is no box, so you are just trying to fold the paper (fabric in this case) in the shape.
To get the corners to stay together I folded then sewed the edge of where the long and short sides meet. Look at the pictures. The final picture is what it should look like if you did everything right.
Step 5: Getting someting... finally!
The key here is that the flat side of the core is facing out and being stapled on. resulting in the pillow being perfectly flat on the hard side.
First, line up the core to the pillow case and staple one long side. The do one of the short sides, then the other long side. I used a heavy duty stapler with 1/4" staples. Be careful with this.
You should have left one side open. Before you staple this side closed you want to stuff the pillow with stuffing foam fr polyfill . Stuff it to the harness that you like to have when done. Then staple the final side.
Check out the pictures.
Step 6: Pretty much done
This is where the careful work in step 3 and 5 comes into play. if that surface was flay, then you should have no problems. Just rough up the bottom of the "lapdesk " surface and slather some liquid nail on it. put the pillow and top together and then weigh it down so that it sticks together.
I used a bunch of books and left it overnight.
Some other things I learned in this project:
In step 4 sewing the corners together took 2-3 trys. so get some help from someone who knows what they are doing.
Instead of putting together a desk core it would have been way easier to use a single piece of wood instead of "making my own.
The handle on the cutting board is really handy, and in theory you can cut out a circle to have a cup holder or whatever you want to make room for on the finished desk. You would just have to have a bigger "top" and compensate for where the hole will fall, when you are making the pillow.