A curved edge is a different problem from a corner. Nothing has to turn 90 degrees; the profile has to follow an arc along its length, which means the legs compress on the inside of the curve and stretch on the outside. A paper U profile can follow a gentle arc without notching, and needs notch relief where the radius tightens.
What a curve does to a U section
On the outside of a bend the legs are pulled apart and the fold opens slightly. On the inside they are pushed together and the legs wrinkle. A short leg tolerates far more of this than a long one.
So the first decision on a curved edge is leg length. A 35 mm leg will follow a radius that a 70 mm leg cannot, and the difference is visible as soon as the piece is offered up.
Specification at a glance
Radius, leg and wall together decide whether the profile follows the arc or has to be relieved with notches.
| Edge | Leg | Wall | Note |
|---|
| Wide radius panel | 50-70 mm | 3-5 mm | Follows without notching |
| Medium radius | 35-50 mm | 2.5-4 mm | Short leg follows |
| Tight radius | 35 mm | 2.5 mm | Notch relief at intervals |
| Drum circumference | 35-40 mm | 2.5 mm | Cut slightly short |
| Coated surface | 35-50 mm | 2.5-3 mm | Clean board, close fit |
Rounded panels, drums and roll goods
Rounded furniture panels and table tops are the easy case: a wide radius, a short leg, and the profile follows without help.
Drums, cylinders and rolls are tighter. Here the protector is often run around a circumference rather than along a straight edge, and the ends meet. A short leg and a light wall follow the surface; notches at intervals let a stiffer profile do the same job.
Where the profile has to sit on a coating that marks, the arc is also where the paper rubs. A clean board and a close fit reduce that movement.
Fitting an arc without creasing it
Start at the middle of the arc and work outward, pressing the profile onto the edge as you go. Starting at one end pushes the surplus to the other and creases it there.
Where the arc closes on itself, cut the length slightly short rather than exact. A piece that meets end to end will lift in the middle as the material relaxes.
Questions buyers ask before ordering
Can a U profile follow a curve?
A gentle arc yes, with a short leg. A tight radius needs notch relief.
What leg for a tight radius?
35 mm with a 2.5 mm wall is the practical limit before notching.
Should the piece meet end to end on a drum?
Cut slightly short. An exact length lifts in the middle as the material relaxes.
Will it mark a coated round panel?
A clean dry board with a close fit does not. Movement between board and surface is what marks.
Can you notch to a radius?
Yes, send the radius and the arc length and we will place the notches.
Tell us the piece size, quantity per shipment and how it is handled at mona@hengnicepacking.com and we will advise on the board build.
