Passive with "estar"?

Question

It is possible, I believe, to form a [sort of?] passive with 'estar' - is it? … Do you have an exercise on that? (perhaps highlighting comparisons with the 'ser' passive).

Accepted Answer

Hola David,
yes, there is a passive formed with estar + past participle. This type of passive is called "pasiva de estado/resultado". It is not always included in the types of passive sentences in books. 
The passive sentence using estar + participle is expressing "the result of an action" (not the process of an action expressed with ser). How to form it:
estar (conjugated) + past participle (agreeing with the subject)
For example, compare these two sentences, one with ser and the other one with estar:
1. Las puertas del colegio son cerradas a las 5 de la tarde.
2. Las puertas del colegio están cerradas a las 5 de la tarde.
1. is conveying the progress of the action, while 2. is talking about the result. 
The result in 2. is a result of having first gonethrough the process in sentence 1. 
We don't have anything at the moment in the system as passive with estar. I am noting it down.
Un saludo
Inma

Answer

Thanks Inma … I used the alternative form in the B2 writing exercise "Everlasting love in Caazapá " by writing: "Sus aguas están conocidas por todos los lugareños".

Answer

… but I failed to apply the rule later, in the same exercise - when I answered (and was corrected): "Es como si estas aguas fuesen benditas [< Wrong !] > estuvieran benditas [< Right] … I should also have got a clue from the use of 'benditas' (the irregular past participle, which is more like an adjective) instead of 'bendecidas'.