The quality of Tesla’s cars suffers any time the company dramatically scales up production, CEO Elon Musk admitted in a February 2nd interview. Musk also said that Tesla was making cars so fast near the end of 2020 that it was messing up the paint jobs.

Tesla has gotten a lot of criticism for the quality of its cars, especially after it started making them at relatively high volumes with the Model 3 and Model Y. But in the interview with industry analyst Sandy Munro, Musk was unusually candid about quality control problems.

“It took us a while to kind of iron out the production process. Friends ask me: ‘When should I buy a Tesla?’ And I’m like: ‘Well, either buy it right at the beginning, or when the production reaches a steady state,’” Musk said in the interview. “But during that production ramp, it’s super hard to be in vertical climb mode and get everything right on the little details.”

Munro then asked why his brand new Model 3 sedan had paint issues, when another one built a month later that he saw was “spectacular.” Musk replied that Tesla had improved its paint quality “toward the end of last year, even in the course of December.”

While the Model 3 is now more than three years old, Tesla spent much of 2020 trying to hit an ambitious target set by Musk of selling 500,000 vehicles. That push apparently led to more quality problems with the paint.

“One of the things that was happening when we were ramping production was the paint wasn’t necessarily drying enough,” Musk said. “So, it’s like, if you go faster… it’s like, you just discover these things. Like, If we knew them in advance, we would fix them in advance,”

Munro is well known for tearing down cars of all types, but his critiques of Tesla’s vehicles are especially popular. His examination of a Model 3 in 2018 was particularly tough, comparing the quality to a Kia from the 1990s. “I cant imagine how they released this,” Munro said at the time.

“I thought your criticisms were accurate,” Musk said Tuesday.

It’s one of the more illuminating interviews Musk has granted in a long while. He and Munro also went deep on a number of other Tesla topics, like the company’s custom seats, how it’s trying to avoid similar quality problems with the Model Y SUV, Autopilot, and more.