In Bereishit Rabbah chapter 52 and Vayigmal: Miyitzahar. And it is explained in the Me'or Einayim that he was twelve years old (this is Year 2060), and then Hagar was expelled, and Yishmael was twenty-seven (see there in Me'or Einayim). Therefore at that time was the Akeidah (see Year 2048).

And Yishmael and his mother Hagar dwelt in the wilderness for many days, and afterward they went to the land of Egypt and she took for him a wife [(in the Yalkut, section 94, from the daughters of Moav and Asiyah is her name)] and her name was Merivah, and she conceived and bore him four sons and one daughter. And they went and returned to the wilderness, and God gave him—on account of Avraham his father—sheep and cattle, and he multiplied greatly, but the face of his father he did not see.

And it was after some days [(in Pirkei DeRabbi Eliezer, chapter 30, after three years)] that Avraham said to Sarah, "I will go and see my son Yishmael, for I desire to see him." And he went to the wilderness and arrived at Yishmael's tent at midday. He found his wife and children but Yishmael and his mother were not with them. Avraham asked, "Where is Yishmael?" and she said, "He went to the field to hunt," while Avraham was still sitting on the camel, for thus he had sworn to Sarah that he would not descend from the camel to the ground.

He said to her, "My daughter, give me a little water, for I am weary and tired from the journey." She said, "We have neither water nor bread," and she went into the tent and did not look at Avraham nor ask him who he was, but she struck her children and cursed them and cursed Yishmael her husband and reviled him. Avraham became very angry and it was evil in his eyes. Avraham called her to come out to him and she came out.

Avraham said to her, "When your husband Yishmael comes, tell him: 'Behold an old man from the land of the Philistines came seeking you,' and describe his appearance to him.

And say: 'Thus said that man: Remove the peg of the tent and put another peg in its place.'" [(The Midrash says: "Change the threshold of your house.")] And he returned on his way. When Yishmael returned from hunting, he and his mother, his wife told him these words. Yishmael understood that it was his father who had not been honored by her, and he heeded his father's voice and divorced her, and she went away.

Afterward Yishmael went to the land of Canaan and took another wife [(from his father's house, and Fatimah was her name, as the Midrash says)]. He brought her to the tent in the place where he had been. After three years [(Bereishit Rabbah and Pirkei DeRabbi Eliezer)] Avraham said, "I will go again and see Yishmael." He rode on his camel and came to the wilderness, to Yishmael's tent, at midday. His wife came out from the tent.

He asked about Yishmael and she said, "He is not here, my lord, for he went to hunt in the field and to tend the camels." She said, "Please turn aside, my lord, to the tent and eat a piece of bread, for your soul is weary from the journey." He said, "I will not stay, for I must hasten on my way, but give me a little water, for I am thirsty." She hurried and ran to the tent and brought out water and bread and set them before him. She urged him greatly to eat, and he ate and drank and his heart was glad.

He blessed Yishmael his son, and finished eating and blessed HaShem. He said to her, "When Yishmael comes, tell him: 'Behold an old man came' etc.

'Thus said the peg that you placed here in the tent is very good; do not remove it,' etc." Yishmael came and his wife told him with joy, etc. Yishmael knew that it was his father, and Yishmael blessed HaShem. Yishmael took his wife and children and his possessions and went to the land of the Philistines to his father, and he dwelt with his father for many days. And Avraham dwelt in the land of the Philistines for many days, twenty-six years [(this is until Year 2085).

Sefer HaYashar].