Spectrum ReFill LW-ASA UltraFoam Light Grey, 1,75 mm / 750 g

ReFill LW-ASA UltraFoam by Spectrum is a spool-less filament wound onto a cardboard core, compatible with reusable Bambu Lab spools and self-printed Spectrum spools* – no additional adapters required.

*Click here to access the STL files for printing your own Spectrum spools.

Spectrum LW-ASA UltraFoam is a specialised high-performance filament that combines the weather- and UV-resistant properties of ASA with active foaming technology. Through controlled expansion during the printing process, significant weight reductions can be achieved – in extreme cases, up to three times the original volume, with a reduced density of approximately 0.33 g/cm³. This makes the material ideal for applications where low weight, mechanical strength, and weather resistance are equally important.

The foaming is activated by specially added additives that begin to expand at around 230 °C. The maximum effect is reached within a temperature range of 270 °C to 285 °C. At lower temperatures, the material behaves like standard ASA 275, allowing flexible adaptation to varying requirements and print settings. Thanks to this controllable expansion, material flow can be reduced by up to 66%, significantly lowering both part weight and material usage.

Despite its low density, the material impresses with mechanical stability, good dimensional accuracy, and excellent weather and UV resistance – qualities that make it particularly suitable for outdoor use. Typical applications include lightweight structures such as drone components, RC aircraft models, air ducts, or structural housings where every gram counts.

The printed parts have a matte, slightly rough surface that effectively conceals layer lines and gives the finished object a high-quality, technical appearance.

Note: The degree of expansion affects the perceived colour – the more the material foams, the lighter it appears. This visual effect should be taken into account during the design process!