The short answer: a mildly warped board can often be bent back by hand and pressed flat under heavy books. A badly warped board is not worth the trouble, so replace it. Boards are a few dollars, and a warped board ruins every project you build on it.
Warping happens when heat hits the plastic unevenly. Most of the time it is our own doing, which means it is preventable.
Why pegboards warp
- The iron touched the board: one hot pass over bare plastic is enough to curl a corner.
- Heat too high: high settings soften the plastic even through paper.
- Forcing it off while hot: lifting a hot board bends the softened plastic.
Paper too thin: a single layer of parchment lets heat through faster than the board can handle.
How to fix a warped board
- Bend it gently the opposite way by hand. Go slow; plastic cracks if you force it.
- Set it between two flat boards and stack heavy books on top for a day.
- Test it on a flat table. If it still rocks, repeat once. If nothing changes, replace it.
How to avoid warping
Use the tape method and iron the beads off the board, or keep the iron moving on medium heat with paper between the iron and the plastic. Our guide to ironing large projects covers heat control in detail, and the pegboard size guide helps you pick boards that match the projects you build. If a board is past saving, a replacement from our shop costs less than a coffee.