Question 1

Do I need CAD software to design a concrete tray?

Accepted Answer

No. Pick a quick-start shape, then set the size, the rim width, the floor thickness and the wall angle. Everything runs in your browser and you download a printable STL.

Question 2

Is this the tray or the mold?

Accepted Answer

It is the master: a solid shaped exactly like the finished tray, recess and all. You take a silicone mold off it and cast concrete or jesmonite into that. The Use in a mold generator button hands the shape straight over.

Question 3

Will the tray come out of the mold?

Accepted Answer

The rim is the widest point by design, so a tray lifts straight out. The wall angle controls how strongly it releases: four to eight degrees is comfortable. Flutes are the exception, because every groove is a parallel-sided slot, so a fluted tray needs wall angle too or a flexible mold.

Question 4

How thick should the rim and floor be?

Accepted Answer

Six to eight millimetres for concrete. Thinner than about five and the rim tends to crack coming out of the mold, which is the most common first-cast failure on a tray. The designer warns you when either goes below that.

Question 5

How much concrete will it take?

Accepted Answer

The sidebar shows the volume as a weight of concrete while you change the shape, plus how deep the recess is, so you can size a batch before printing anything.

Parametric Concrete Tray, Dish and Bowl Designer