Microfibre for Car Detailing: GSM, Pile and Which Cloth to Use

Most swirl marks in car paint are not caused by car washes, weather or bad luck. They are caused by whatever touched the paint during washing and drying. That makes the humble microfibre cloth one of the most important tools you own, and choosing the wrong one, or looking after it badly, undoes the work of every product you put on the car.

This guide explains what microfibre is, what the numbers on the label mean, which cloth to use for which job, and how to keep your cloths working properly.

What microfibre actually is

Microfibre is a synthetic fabric made from extremely fine fibres, usually a blend of polyester and polyamide (nylon). Each fibre is finer than a single strand of silk, and during manufacture the fibres are split, giving each one a wedge-shaped cross section with tiny channels along its length.

That split structure is what makes microfibre so different from cotton. The channels trap dirt, dust and oils inside the cloth rather than pushing them across the surface, and they hold several times the cloth's own weight in water. The polyamide content adds softness and absorbency; the polyester gives strength.

Cotton, by contrast, has coarse fibres that tend to push dirt around, leave lint behind and hold grit against the paint. An old T-shirt or bath towel is one of the fastest ways to put swirls into a car.

What the numbers on the label mean

GSM stands for grams per square metre. It tells you how dense and heavy the cloth is. A lower GSM cloth is thinner and more precise, a higher GSM cloth is plusher, softer and holds more liquid. Higher is not automatically better. It depends on the job.

The blend, such as 70/30, is the ratio of polyester to polyamide. More polyamide generally means a softer, more absorbent cloth.

Pile is the length and structure of the fibres:

• Short pile is precise and levels liquids cleanly, which makes it right for removing coatings.
• Closed pile has a tight, smooth weave that does not hold product or shed fibres, so it leaves glass streak-free.
• Medium and long pile are plusher, lift residue gently and hold plenty of water, which suits polish removal and drying.

Edgeless cloths are laser-cut with no stitched border and no label. Stitched edges and labels are hard and are a common cause of fine scratches, particularly when a cloth is folded and used near its edge.

Which cloth for which job

No single cloth does everything well. Using the right one at each stage is what separates a clean car from a properly detailed one. The Ultracoat range is built around that idea. Every cloth is edgeless Korean microfibre, 40 × 40 cm and safe on coated surfaces.

Yellow Bahama: the everyday cloth

250 GSM and 70/30 polyester to polyamide. This is the general-purpose cloth for dashboards, door cards, shuts, trim, wheels, engine bays and interior glass. It is deliberately the most affordable in the range, so you can buy several packs, use it for the dirty jobs and keep your specialist cloths clean for the work that needs them.

Gentle Buff: for coatings

320 GSM short pile. When you apply a ceramic coating, a fluffy cloth grabs at the curing product and drags it, leaving high spots and streaks. A short pile levels it cleanly. This is the cloth for removing the excess after applying Skyline, Magnite, Aurora, Carbon or ONE, and for the final buff.

Purple Blaze: for glass and degreasing

320 GSM closed pile. Because the fibres do not open up and hold product, it does not redeposit residue, which is why it leaves glass without streaks. It is also the right cloth for the panel wipe with Finest Wipe before a coating goes on, and for levelling a glass coating such as Vista.

Silky Finish: for polish removal and drying

400 GSM, ultra-soft, medium pile. The plushest cloth in the range. After polishing, it lifts compound residue off freshly corrected paint without dragging it back across the finish. For drying, it holds a lot of water and glides rather than drags, protecting the paint during the riskiest part of the wash. It is also the right cloth for applying waxes and sealants.

Soft Touch: the wash mitt

A 1500 GSM Korean microfibre wash mitt. The deep, dense pile pulls dirt up and away from the paint instead of trapping it against the surface, and it holds plenty of shampoo to keep the panel lubricated. A sponge does the opposite: grit sits on its flat face and gets ground into the clear coat.

How to wash microfibre

Microfibre only works while its fibres stay open and clean. Wash it wrongly and it turns into an ordinary cloth.

• Wash separately from other laundry. Cotton lint clogs the fibres.
• Keep it cool: 40°C or below, and never above 60°C, which deforms the fibres.
• Never use fabric softener or bleach. Softener coats the fibres and destroys absorbency, and it is the most common way people ruin good cloths.
• Use a mild detergent and an extra rinse.
• Air dry, or tumble dry on low heat only.
• Keep glass and coating cloths apart from cloths used on wheels, engine bays and interiors, even in the wash.

When to retire a cloth

Any cloth or mitt that has touched the floor is finished for paintwork. There is no reliable way to get embedded grit back out, and one pass over a panel is enough to scratch it. Downgrade it to wheels or engine bays, or throw it away.

The same goes for any cloth that has picked up cured coating, or that feels stiff and no longer absorbs properly after washing. Microfibre is cheap compared with polishing out swirls.

The most common mistakes

• Using one cloth for everything, so wheel grit ends up on the paint.
• Drying with a bath towel or chamois instead of a plush microfibre.
• Using a fluffy cloth to remove a coating and leaving high spots.
• Cleaning glass with an open-pile cloth and chasing streaks.
• Washing cloths with fabric softener.
• Pressing too hard. A good microfibre does the work with light pressure.

Summary

Microfibre works because of its split, ultra-fine fibres, which trap dirt instead of dragging it and absorb far more than cotton. Choose the cloth by the job: an everyday cloth for general work, short pile for coatings, closed pile for glass and degreasing, and ultra-soft for polish removal and drying. Wash them cool, without softener, and retire any cloth that has been dropped. Get that right and every other product you use on the car works better.

See the full range in our accessories collection, and for how the cloths fit into a full detail, read our guide on how to apply a ceramic coating at home.