Why records warp, and how we mostly stop it

Nobody emails us excited about a warp. Fair enough. Let’s talk about where they actually come from, because it’s rarely the dramatic cause people assume.

The press cycle, briefly

PVC pellets, roughly 135 grams for a standard 12 inch LP, get heated to around 150 degrees Celsius until soft, then squeezed between two stampers under something like 100 to 150 tonnes of pressure for about 25 to 30 seconds. After that the record needs to cool under continued, even pressure before the press opens. Skip or rush that cooling stage and you’ve built a warp into the disc before it’s even left the machine.

Heat is the main enemy, always

Vinyl starts softening well below temperatures that feel dangerous to a person. A car dashboard on a warm day, a window sill in direct sun, a radiator across the room, all of these can get a sleeve hot enough to let gravity do slow, quiet damage over hours. This is genuinely the single biggest cause of warps we see in returned records, and it happens after the record leaves us, not during pressing.

Cooling and stacking matter more than people think

Fresh pressings come off Bertha (our secondhand 1978 press, still the workhorse here) warm and slightly pliable. We stack them on cooling racks rather than directly on top of one another, because:

• Stacking warm discs lets the weight above gently deform the ones below
• Uneven cooling across the surface of a disc leaves internal stress that shows up as a warp weeks later
• A disc cooled flat, under light even pressure, holds its shape far better long term

Anything that comes off looking even slightly off gets pulled and goes in the reject crate by the door rather than into a sleeve.

A warp usually isn’t a mystery. It’s a record that got hot, or got cooled unevenly, and nobody noticed in time.

What actually helps at home

Store records vertically, not flat in a stack, and not leaning at an angle against a shelf edge for months, which slowly bends the top discs in a stack. Keep them out of direct sun and away from radiators. If a record does pick up a mild warp, some people swear by sandwiching it between glass and a gentle, controlled low heat, and it can genuinely help with minor cases, though we’d rather talk you through it than have you experiment on a record you love.

Why we don’t chase zero defects at all costs

We could, in theory, slow the whole line down and cool every disc for twice as long to chase a theoretical zero percent warp rate. We don’t, because at some point you’re just making records that take six months to press instead of six weeks, and most listeners would rather have the record. What we do instead is check flatness on a light table before anything ships, and anything borderline doesn’t leave the building.

If your last pressing arrived less than flat, tell us the format and we’ll sort it. Learn about our formats.