This is about all there is to it as for making the tube.  Split a piece of pvc pipe down both side on the table saw and add some caps that have also been split and holes cut in the centers for a stem place.  Use tape to hold the caps together and they will hold the pipe together.  Remove leaves, install the bottom cap onto stem, set pipe halves in, fill it, water it and install top cap. A coarse guitar string can be used to saw the stem off under the bottom when it's ready. 

This would absolutely be way heavy for a lateral limb using sand.  One might use perlite or whatever.  I just used what I had and you can't see there's a rebar support behind it fastened with box tape.  Not even sure how one would fill a horizontal tube and water it.  Ya'll can figure that one out.  With outdoor fig mounds like Unk Lake Spur in the photo, maybe another topic, I pretty much have a good supply of straight up vertical limbs to play with.

 

Stick around Charlie, I promise I will stop bashing..... Richie who? :-)

Charlie, I'm really enjoying reading your posts and learning from your experiments. I've been trying something similar to the single node air layering and I'm wondering why it is that you cut it from the tree before it goes dormant?

Scott

Thank you Charlie. When you cut up the big air layer, how far above each node do you make the cut? Looing at photos of single-node cuttings to be rooted, I was surprised by how much wood was left above each node. I couldn't figure out the purpose of all that wood above the node.

That's awesome. I imagine you would need the roots to be fairly mature so the don't break in the process. How long did you leave it on the tree?