Stem Strength when Cloning

How do you keep stem strength when cloning? I've tried Al's method and I have a bubble cloner going right now.

The bubble cloner is showing more success than the RW did, however most of them are drooped over and some won't recover from that part alone.

Is there a technique when cloning to strengthen the stems before or while cloning? I have a fan on the mothers and the stems seem very sturdy before cutting, but then they just turn into wet spaghetti regardless of thickness.

Any ideas? Temp and ventilation don't seem to be the problem, I cut sterile as I could, only thing I can think of is that there is a step missing somewhere in the cutting process. Ideas?

I've never had clone stems bend, but maybe taking a little older cuts would help. Most of mine, while quite small lower tips, are already woody when I take them.

do you even have a lid over the clones to keep the humid up for them when they are rooting? if not then you must do that because they can't get water into them from teh rooting area, they absorb water through their leafs