Reading an RDP Data Sheet

A technical data sheet looks like a list of unrelated figures. Read in the right order, it is a short description of how the powder will behave in a mortar.

Bulk Density

Bulk density describes how the powder was made as much as what it is. Spray dried particles with a hollow structure are lighter, flow better and redisperse faster; denser particles pack into a smaller silo.

For a producer, bulk density decides silo volume, dosing screw settings and the feel of the powder in the mixer. Two powders with the same chemistry but different density behave differently on the same line.

Ash Value

Ash is what remains after the polymer is burned away, mostly mineral antiblocking agent and residue. A higher ash figure means less polymer per kilo of powder.

That is why ash is the first thing to compare when two quotations look too far apart. The cheaper powder often carries more mineral and less polymer, and the dosage has to rise to compensate.

Film Forming Temperature

The minimum film forming temperature decides the lowest temperature at which the polymer still coalesces into a film. It is the number that connects a data sheet to a construction site.

A powder with a low value tolerates cold application and gives a flexible film; a high value gives a hard film and needs warmth. Neither is better in the abstract.