Oregon’s favorite folk sisters recently returned from “band camp.” Thankfully, stories that could veer into American Pie’s “This one time, when I was at band camp…” territory don’t end with sticky flutes but with the Shook Twins recording their fourth album What We Do with producer Ryan Hadlock. Hadlock is the same dude behind The Lumineer’s self-titled, Grammy-nominated record (remember the summer of 2012’s “Ho Hey” frenzy?). The Shook Twins host an album release party Friday, May 2, at McDonald Theatre.

“We’re kinda buddies with The Lumineers,” Katelyn Shook tells me over the phone from the band’s tour bus. “We played a show with them before they warped to level 10. They played in our basement one night in Portland.” From this friendship, they were able to reach out to Hadlock.

Before long, the band was recording at Hadlock’s Bear Creek Studio outside Seattle. “It’s like this old barn totally remade into this multimillion dollar studio,” Shook says, fondly remembering a nearby creek with chirping frogs (they make a cameo on “Toll Free”).“We all stayed up there together.”

And “We” has morphed from the twins (Laurie is the other half) — who, combined, provide vocals, guitar, glockenspiel, mandolin, banjo, bass, ocarina, djembe and beatboxing — to a five-person outfit including Anna Tivel on fiddle and mando, Kyle Volkman on upright bass and Niko Daoussis on mando, electric guitar and drum kit.

“This is the first album we have drums on,” Shook says. “Electric guitar too. It’s got a little bit more soul and rock-y, groovy style.” The album’s theme is loose; when pushed, Shook says it ranges from love to the apocalypse. “There are a couple of love songs, which is atypical for us,” she says. The upbeat “end-of-the-world” ditty “Shake” premiered on USA Today’s website.

There’s no doubt that the Shook star is rising fast, yet the band still eschews the conventional record-label route; they raised $26,000 via Kickstarter to produce What We Do. “It’s an excellent way to make a record,” Shook says. “You can get funding from your fans and build it together. Record labels take such a big cut. That’s why we decided to do it.”

Fruition, another Portland folk-rock favorite, joins the Shook Twins for the first time at the McDonald. “We are really good friends,” Shook says of the two bands. “We’ve been trying so hard to do some co-bills with them for a long time.”

The Shook Twins kick off their album release party with Fruition 8 pm Friday, May 2, at McDonald Theatre; $15 adv., $20 door.