"Salza & Co. fraudulently quote Fr. Gregor Hesse against me on the point of defection from the faith and the Church. In order to deceive their readers into believing that Fr. Hesse was of the same opinion as Salza/Siscoe, who maintain that heretics are not severed from the Church without a judgment from Church authority, they quote Dr. Hesse’s words which explain that 'there is no formal schism unless it is declared schism'. Salza & Siscoe oafishly interpret the theologian’s words to mean that there is no schism unless the Church authority declares it! Long before the days of YouTube, by which Salza & Siscoe access the words of Fr. Gregory, I lived in Rome and earned my degrees at the same Pontifical University where he earned his theological degrees. We spent many evenings together in Rome discussing Philosophy, Theology, and ecclesiastical issues. We met many times afterward in Canada, USA, Vienna, Rome, Los Angeles, Belize, etc. – we were the closest of friends from 1975 to 2006. (We first met on the assembly line at the Mercedes-Benz factory in Germany while working at our summer jobs in 1975) No one on earth knows the theological mind of Fr. Gregor Hesse as well as I do. It was I who suggested and convinced him to write his doctoral thesis on the Theology of Chesterton. What Fr. Gregor was saying (and any academically qualified theologian knows this), is that for someone to be a schismatic, that one must declare himself to be separated, either by words or actions, and not the other way around."

Kramer, Paul. To deceive the elect: The catholic doctrine on the question of a heretical Pope . Kindle Edition.  Footnote 721.

Heresy or apostasy or schism incur automatic excommunication.  Also, read the first part of Fr. Kramer's comment.  He is speaking about heresy in that part.  Regardless, are you sure that Salza and Siscoe quoted Fr. Hesse correctly?

My advice to you is to stop listening to Salza and Siscoe who, according to Fr. Kramer, have no formal learning in theology and do not read Latin.  Rather, get Fr. Kramer's two volume set (so far).  From those volumes, you will learn from someone who studied at the Pontifical University of St. Thomas Aquinas in the 1970s under the Dominicans, and has refuted Salza and Siscoe on many points.  Salza is the same man who now says the SSPX is in schism.

“St. Robert Bellarmine, commenting on the fourth opinion in De Romano Pontifice liber ii cap. xxx, quotes St. Jerome (d. 420 AD), one of the four major Latin Fathers, who teaches with the unanimous consensus of the Fathers, ‘Jerome comments on the same place, saying that other sinners, through a judgment of excommunication are excluded from the Church; heretics, however, leave by themselves and are cut from the body of Christ‘. Bellarmine states explicitly that the heretic is cut off from the body of the Church before any sentence of excommunication comes into effect: ‘Yet heretics are outside the Church, even before excommunication, and deprived of all jurisdiction, for they are condemned by their own judgment, as the Apostle teaches to Titus; that is, they are cut from the body of the Church without excommunication, as Jerome expresses it.'”
Kramer, Paul. To deceive the elect: The catholic doctrine on the question of a heretical Pope . Kindle Edition. [Emphases in original]

What was the gist of St. Bellarmine's example of Pope St. Celestine and Nestorius?

“St. Robert Bellarmine, commenting on the fourth opinion in De Romano Pontifice liber ii cap. xxx, quotes St. Jerome (d. 420 AD), one of the four major Latin Fathers, who teaches with the unanimous consensus of the Fathers, ‘Jerome comments on the same place, saying that other sinners, through a judgment of excommunication are excluded from the Church; heretics, however, leave by themselves and are cut from the body of Christ‘. Bellarmine states explicitly that the heretic is cut off from the body of the Church before any sentence of excommunication comes into effect: ‘Yet heretics are outside the Church, even before excommunication, and deprived of all jurisdiction, for they are condemned by their own judgment, as the Apostle teaches to Titus; that is, they are cut from the body of the Church without excommunication, as Jerome expresses it.'”
Kramer, Paul. To deceive the elect: The catholic doctrine on the question of a heretical Pope . Kindle Edition. [Emphases in original]

“Hence, if anyone shall dare — which God forbid! — to think otherwise than as has been defined by us, let him know and understand that he is condemned by his own judgment; that he has suffered shipwreck in the faith; that he has separated from the unity of the Church; and that, furthermore, by his own action he incurs the penalties established by law if he should are to express in words or writing or by any other outward means the errors he thinks in his heart.”
(Pope Pius IX, Ineffabilis Deus, 1854) [Emphases mine]

The heretic is condemned by his own judgement and separated from the Church.  Any penalties established by the Church in her law (e.g., automatic excommunication) are in addition to the heretic’s self-condemnation. 

"After the reception of baptism, if anyone, retaining the name Christian, pertinaciously denies or doubts something to be believed from the truth of divine and Catholic faith, [such a one is] a heretic;"
(Canon 1325 § 2, 1917 Code of Canon Law)