Materials — GlyphForm

What it is

PLA (polylactic acid) is a thermoplastic made from fermented plant starch — typically corn, sugarcane, or cassava. It's a bioplastic, meaning its raw material is renewable and plant-derived rather than petroleum-based. In the 3D printing world, PLA is the most widely used filament material, and there's a good reason for that: it produces exceptional results.

Why we use it

We use matte PLA for our indoor lettering because it produces the best surface finish of any FDM printing material, full stop. Matte PLA contains fine mineral additives that diffuse light across the surface, which does two important things: it hides the layer lines that are inherent to 3D printing, and it produces a smooth, non-reflective finish that looks and feels like a considered, designed object rather than a 3D print.

That surface quality is why we chose it. GlyphForm lettering isn't trying to disguise the fact that it's 3D printed — but we are committed to making the print quality as high as it can be. Matte PLA lets us deliver lettering with a refined, premium texture straight off the printer, with no post-processing, no painting, and no filler. What you receive is the raw printed material at its best.

PLA also prints with excellent dimensional accuracy and very low warping, which matters when you're producing lettering where every curve and edge needs to be crisp.

The colour range

PLA offers the widest colour range of any 3D printing filament. Because it's the most popular material in the industry, manufacturers produce it in an enormous variety of colours — from muted, architectural tones through to bold primaries. Our curated palette focuses on colours that work well for signage and interior applications, but the range available to us is broad and we can expand it over time.

The honest limitations

PLA has a relatively low glass transition temperature — around 55–60°C. That means in direct sunlight or high heat, it can soften and deform. In a UK summer, surfaces in direct sun can easily reach these temperatures. Prolonged UV exposure also causes PLA to become brittle, fade, and lose structural integrity over time. Indoors, none of this is a concern — PLA lettering in a hallway, reception, office, or retail space will hold its shape and colour indefinitely. But we won't sell you PLA for an exterior application and hope for the best. If your lettering is going outside, we'll point you to ASA.

PLA is also more brittle than engineering plastics. It's strong and rigid, but it doesn't flex — it snaps. For wall-mounted signage lettering this isn't a practical issue (it's not being bent or dropped), but it's worth knowing.

The environmental picture

PLA is derived from renewable plant sources rather than fossil fuels, and its production generates significantly fewer greenhouse gas emissions than conventional plastics. It's often described as “biodegradable,” but that needs context: PLA only biodegrades under industrial composting conditions — high temperature, high pressure, controlled environments. It won't break down in a home compost bin, in landfill, or if left outdoors. In an industrial composting facility it can decompose in around 60–90 days; without those conditions, it persists much like any other plastic.

What PLA does offer over petroleum-based plastics is a lower carbon footprint in production and a feedstock that doesn't rely on finite fossil resources. It's a genuinely better starting point — but we won't overstate it. It's not a magic solution to plastic waste, and responsible disposal still matters.

What it is

ASA (acrylonitrile styrene acrylate) is an engineering-grade thermoplastic developed specifically as a weather-resistant alternative to ABS. It's a petroleum-based plastic — there's no bio-based origin story here — but it's engineered to do something that PLA and most other 3D printing materials simply can't: survive outdoors, long-term, without degrading.

Why we use it

ASA is the right material for any GlyphForm lettering that will live outside. It offers outstanding resistance to UV radiation, meaning it won't yellow, fade, or become brittle under prolonged sun exposure. Independent testing shows ASA retaining its colour and mechanical properties after years of outdoor weathering — not weeks or months, but years.

Beyond UV resistance, ASA handles rain, frost, humidity, and temperature fluctuation without issue. Its glass transition temperature sits around 100°C, which means it won't soften in any climate condition the UK (or most of the world) can throw at it. Where PLA starts to give at 55–60°C, ASA doesn't flinch until well above boiling point.

ASA also produces a naturally matte surface finish with slightly less visible layer lines than standard ABS, which works in our favour for lettering applications. The finish isn't quite as refined as matte PLA — PLA's mineral additives give it an edge on pure surface quality — but for outdoor signage where durability is the priority, ASA's finish is more than good enough.

The colour range

ASA is available in a more limited colour range than PLA. Because it's a more specialised material with lower market volume, manufacturers produce fewer colour options. The core palette — blacks, whites, greys, and a selection of primary and architectural colours — covers most signage needs well. But if you're looking for a very specific or unusual colour, PLA's range will have more options.

We're honest about this trade-off: you get outdoor durability in exchange for a slightly narrower colour selection.

The honest limitations

ASA is a petroleum-based plastic. It doesn't carry the renewable-origin story that PLA does, and it's not biodegradable under any conditions. It's durable by design — which is the point for outdoor applications, but it does mean it persists in the environment like any conventional plastic.

ASA is also slightly more expensive than PLA, both as a raw material and to print. It requires higher printing temperatures (240–260°C versus PLA's 190–220°C), an enclosed printer chamber to prevent warping, and more careful process control. These factors are reflected in the pricing of our outdoor-rated products.

From a printing perspective, ASA can emit fumes during production that require proper ventilation — this is a manufacturing consideration that doesn't affect the finished product, but it's part of the picture.

The environmental picture

ASA is a traditional petroleum-derived plastic, and we won't dress that up. Its production relies on fossil fuel feedstocks and it doesn't biodegrade. However, the counterpoint is longevity: a well-made ASA letter installed outdoors will last for many years without needing replacement. A PLA letter used outdoors would degrade within months and need to be replaced, potentially creating more waste over time.

The most environmentally responsible choice is the right material for the right application. PLA indoors, ASA outdoors. Using the wrong one either way creates waste — either through premature failure or through using a more resource-intensive material where it isn't needed.

	PLA	ASA
Best for	Indoor use	Outdoor use
Surface finish	Excellent matte finish, minimal layer lines	Good matte finish, slightly more visible layers
UV resistance	Low — will degrade in sunlight	Excellent — years of outdoor exposure
Heat tolerance	~55–60°C — softens in direct sun	~100°C — no concern in any climate
Colour range	Wide — extensive palette available	Narrower — core architectural colours
Material origin	Bio-based (plant starch)	Petroleum-based
Biodegradable	Industrial composting only	No
Relative cost	Lower	Higher — outdoor premium

The right material for the right environment. We'll always guide you to the honest choice.

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