The Thermals. (From left: Hutch Harris, Kathy Foster, Westin Glass.)

Portland punk band The Thermals makes progression look easy. Beginning with its 2003 lo-fi debut More Parts Per Million, the band has gradually expanded its sonic palate with each subsequent album, be it 2006’s epic The Body, the Blood, the Machine or 2009’s death-centric Now We Can See while retaining its core identity: explosive energy, loud guitars, sing-a-long choruses, all delivered in three minutes or less.

Personal Life, released in September on Kill Rock Stars, finds The Thermals tackling another universal theme — relationships — which breaks from its previous efforts but is unmistakeably still a Thermals record. DCist spoke with bassist Kathy Foster last month before the band kicked off its current tour, which hits the Black Cat on Friday, to discuss the music video process, the joy of cover songs and why it’s important to never talk down to an audience of four-year-olds.