Silk filament: how to get the shiny finish

Silk filament is the reason some prints look like polished metal and others look like plastic. Gold and copper figurines, shimmering vases, and the colour-shifting fidget toys that fill social media feeds are almost all printed in it. It prints on the same machines as ordinary PLA, usually with the same settings and a few small changes, which makes it one of the cheapest ways to make a print look expensive.

What silk filament actually is

“Silk” describes a finish, not a separate plastic. Almost every silk spool is PLA, or PLA+, blended with additives that make the surface glossy and light-catching. Manufacturers do not publish their recipes, so treat it as a family of similar products rather than one material with one set of properties. That is also why two brands of “silk gold” can look quite different.

Because it is PLA underneath, it keeps PLA’s strengths: it prints at modest temperatures, needs no enclosure, has a low smell, and works on any printer that handles standard PLA.

Single, dual, triple and gradient

• Single colour silk — gold, silver, copper, bronze and bright metallics. This is the “polished metal” look.
• Dual and triple colour silk — two or three colours extruded side by side in the same strand. Which colour you see depends on the angle you look from, so the print shifts colour as it turns. This is the look behind most colourful fidget toys. It needs no multi-colour hardware: a single-nozzle printer does it on its own.
• Gradient or rainbow silk — the colour changes gradually along the length of the spool, so a tall print fades from one colour to the next.

Dual and triple colour silk looks best on rounded, curved objects, where the changing angle shows off every colour. On a flat face you mostly see one colour. If you want genuinely separate colours in one object, such as a red body with yellow buttons, that is a different job for a multi-colour system: see whether multi-colour printing is worth it.

Not the same as metal-filled, glitter or matte

• Metal-filled filament contains real metal powder. It is heavy, can be polished, and is abrasive, so it wears a brass nozzle quickly. Silk contains no metal and is kind to nozzles.
• Glitter and sparkle filament contains particles that can also be abrasive and can clog small nozzles. See hardened vs brass nozzles.
• Matte PLA is the opposite finish. It hides layer lines and small flaws well, where silk’s shine tends to show them.

How to print it well

Start with the temperatures printed on the spool and a silk PLA profile, which most slicers include. From there, a few adjustments make the biggest difference:

• Slow the outer walls. The shine comes from the outside surface, and a slower outer wall lays it down smoother and glossier. Leave the infill and inner walls at normal speed.
• Try the warmer end of the spool’s range. Silk usually looks glossier printed a little hotter. Go up in small steps: too hot brings stringing.
• Consider a little less flow. Silk tends to swell more as it leaves the nozzle than standard PLA, so a few per cent less flow can sharpen details and tighten moving parts.
• Hide the seam. Every layer starts somewhere, and on a glossy surface that seam catches the light. Set it to the back or to a sharp corner.
• Design out supports where you can. A support scar is far more visible on silk than on matte filament, and sanding it away removes the shine.
• Try spiral vase mode for vases and pots. One continuous wall with no seam is where silk looks its best.

A good first layer matters as much as ever: see first layer calibration.

Keep it dry

Damp silk loses much of its shine, and strings and pops as it prints. Store open spools sealed with desiccant, and dry any spool that has sat out for a while before printing something you care about. See filament storage and whether you need a filament dryer.

Where silk falls short

• It is for looks, not strength. The additives that create the shine tend to weaken the bond between layers, so silk parts snap more easily than standard PLA. Brackets, clips and anything that takes a load belong in standard PLA or PETG: see PLA vs PETG.
• Moving parts need clearance. Print-in-place toys and fidget designs work well in silk, but a hinge with a very tight gap is more likely to fuse. Pick designs with generous clearance, or print a small test piece first.
• It shows flaws. Ringing, uneven walls and blobs are all easier to see on a glossy surface.
• Heat still wins. Like all PLA, silk starts to soften at roughly 55–60 °C. A warm room is fine; a sunny windowsill or a car in summer is not.
• Post-processing kills the shine. Sanding and most paints remove exactly the finish you bought it for.

Good first prints

Vases and pots in spiral mode, figurines and busts, fidget toys and articulated animals, ornaments, gift boxes and cosplay trim all suit silk. A good test is a tall, rounded object: it shows the gloss and, with dual or triple colour silk, the full colour shift.

Buying silk filament

• Compare the price per kilogram. Silk comes as 1 kg spools, bulk packs and multi-colour sets of small spools. Small-spool sets are the easiest way to try several colours but cost far more per kilogram, and 1 kg spools and multi-kilo packs are usually the better value once you know which colours you like.
• Silk PLA or silk PLA+? “PLA+” versions are marketed as tougher. They are worth a look for toys that will be handled a lot, but check the reviews rather than the label.
• Check the diameter. Almost every modern printer uses 1.75 mm.
• Read reviews for colour. Photos flatter shiny filament. Buyer photos of finished prints show the real finish far better than a product image.
• Brand chips are optional. Some printers read a chip on their own brand’s spools to set the filament type automatically. Any 1.75 mm silk PLA still prints fine: you choose the profile yourself.

At the time of writing we track about 280 silk listings on Amazon UK, around half of them dual, triple or rainbow colour. Browse silk filament ranked by £/kg and dual and triple colour filament. Silk is sold as PLA or PLA+, so you can also compare it on PLA ranked by £/kg and PLA+ ranked by £/kg, or browse all filament ranked by price per kilogram. Still choosing a printer? The printer finder recommends one from our reviews.