I can sweep my chimneys thanks to Greenspace's article.
But upon inspection, I can see the thimble needs repair. Looking through sites, I have not found 'How to repair thimble'.

Outside, I am hunting down the 3 step process to repair stucco. The chimney has a stucco finish but broke off in a section. My prior repair was removing all loose material and applying hydraulic cement making the stucco swirls with my hand. It looked great, then fell off after 2 winters. Where can I locate the 3 steps needed for a proper repair?
Thanks for any assistance.

Note to DIY'ers. Hydraulic is wonderful but gloves are a good idea. I had gloves on when repairing but couldn't get the right 'feel' so the gloves came off. The burns/peeling hands took 2 weeks and one container of Bag Balm.

What is underlying the stucco? Concrete block? Was there metal lath exposed on the part that originally fell off? Or was it just one of the top coats of stucco that departed?

The reason why your patch fell off is probably that water got behind it and froze, and popped it off. Maybe a piece of metal lath under it, mechanically attached to the chimney, will help hold the patch on.

Hi Richard! The Stucco is directly on concrete block so I'm getting metal lath and encouraging it into the section that flaked off like sunburned skin. I will carefully cold chisel under the solid stucco and jam that metal lath in.
But I fear I am skipping a step (my ignorance worries me).

I haven't found thimble repair in all the likely DIY sites.. yet. I'll keep looking, I'm not proud.

as far as the stucco finish is concerned. The reason for the falling off is moisture. The top cement cap on the chimney is allowing moisture down behind the stucco finish you applied. You need to seal the cement cap that goes from the edge of the chimny to the thimble that sticks up in the middle. Once water gets in there the freeze thaw cycle will distroy even the best stucco job.

To fix the thimble. Is it a heating chimney or a fireplace/stove chimney.
If its a heating chimney the best way is to reline it with a metal liner.
If it is a fireplace/stove chimney. You need profesional help. They typically remove the chimney if its not to far down but to far to reach or they remove the brick surrounding the offending liner replace the liner and then re-brick around. Not a job for someone who is not experianced in doing so. Also not a cheep repair.

Thanks HCC,

I will call around to find a chimney mason. It's a wood burning stove that gets almost constant use from November through March (most years). The stove enters the thimble at the half way point.
Look on the bright side, the 1 foot section of flacking stucco is 4 feet from the top of the chimney. If they remove the chimney to the thimble, my stucco nightmare is gone.
Thanks everyone for your help.