As this summer temps went from 15~20C to 35C in a matter of hours, and didn't drop down for almost three months, the old "pot getting super heated" issue was a big problem.
Last summer I had tried wet towels around the pots, but it was a difficult logistical approach.
So after I almost lost an important big branch low down on my Calliandra, my wife weaved some protective tubes to be put around the pots, and it worked flawlessly.
It's not pretty, but the health of the bonsai is more important.
Below you can see the sick branch inside a plastic bag to keep the moisture high (thanks LB!).
And yes, I had to do an emergency repot to get rid of the fried dead roots!

Is there anything in the protective tubing? If it works, don't knock it... how much water is in the pan under the tree?
Our summer last year was pretty dry... thankfully not 35C. right now, I'm happy it looks like the frost is over...even though it probably will rain every day for the next two or three weeks...

tubaboy wrote: Is there anything in the protective tubing? If it works, don't knock it... how much water is in the pan under the tree?..

Well, the tissue is anti-heat and being white it reflects some of the heat.
There is always some water in the tray, but we never let it still for more than two days; usually I empty the tray every three days.
Good your summers are not 35, here it gets unbearable sometimes...