πήγνυμι πέπηγα is generally used as perf. pass.
Radical sense, to make fast; intr. and Pass. to be solid :
I.to stick or fix in, ἐν δὲ μετώπωι πῆξε [τὴν αἰχμήν] Il.; π. ἐπὶ τύμβωι ἐρετμόν Od.:— to fix in the earth, plant, Soph.; σκηνὴν π. to pitch a tent, Plat.; (so Mid., σκηνὰς πήξασθαι to pitch their tents, Hdt.):—intr. perf. and Pass., δόρυ δ᾽ ἐν κραδίηι ἐπεπήγει the spear stuck fast in his heart, Il.; ὀϊστοὶ πῆχθεν ἐν χροΐ id=Il.; [ξίφος] πέπηγεν ἐν γῆι Soph.
2.to stick or fix on, κεφαλὴν ἀνὰ σκολόπεσσι π. to stick the head on stakes, Il., etc.: —Pass., πηχθέντας μέλη ὀβελοῖσι having their limbs fixed on spits, Eur.; παγέντες impaled, Aesch.
II.to fasten together, construct, build, νῆας πῆξαι Il.; so Mid., ἄμαξαν πήξασθαι to build oneself a wagon, Hes.
III.to make solid, stiff, hard, of liquids, to freeze, θεὸς πήγνυσι πᾶν ῥέεθρον Aesch.; ἔπηξε (sc. ὁ θεὸς) τοὺς ποταμούς Ar.:—intr. perf. and Pass. to become solid, stiff or hard, γοῦνα πήγνυται the limbs stiffen, Il.; of liquids, to become congealed, freeze, Hdt.; ἅλες πήγνυνται the salt crystallises, id=Hdt.; κρύσταλλος ἐπεπήγει οὐ βέβαιος was not frozen strong, Thuc.