Manufacturer · Fashion Accessories
Upholstery threads are strong synthetic threads for sewing upholstered furniture, car seats, boats, campervans and other products made of heavy materials. Most often they are bonded polyamide or polyester threads ranging from about tex 40 for light seams to tex 210 and above for visible decorative stitching. The choice depends on the material, the load and whether the product will be exposed to sunlight.
How upholstery threads differ from sewing threads
Ordinary sewing threads for clothing are designed for fabrics that are washed, stretch moderately and are worn for a few seasons. Upholstered products work under completely different conditions: thick stacks of leather, vinyl, foam and lining, high tension when the cover is pulled tight, constant friction when sitting, and often light and moisture. That is why upholstery threads are distinguished by:
- continuous synthetic filaments instead of short fibres;
- greater thickness and tensile strength;
- a coating that prevents fraying and overheating in the needle;
- better resistance to abrasion and light;
- winding on large cones for industrial machines.
Types of upholstery thread
Bonded polyamide (bonded nylon)
The most widespread upholstery thread. Very strong, elastic and resistant to abrasion. It is suitable for upholstered furniture and the inner seams of car seats.
Bonded polyester
Similar in strength, but with better UV resistance and lower elongation. It is used for visible seams, dashboards, convertibles and furniture next to windows.
UV-stabilised polyester
With additional protection against the sun. For garden furniture, awnings, canopies, boats and outdoor cushions.
PTFE thread
A special fluoropolymer thread for products that stay outdoors all year round – awnings, marine covers.
Spun polyester and core-spun
Softer threads for light textile covers, cushions and linings where maximum strength is not needed. For these, see our sewing threads.
Upholstery threads by application
| Product | Recommended thread type | Approximate thickness |
|---|---|---|
| Upholstered furniture – fabric | bonded polyamide or polyester | tex 40–70 |
| Upholstered furniture – leather | bonded polyamide or polyester | tex 70–90 |
| Car seats | bonded polyamide for inner seams, polyester for visible seams | tex 70–90 / 135–210 |
| Dashboards and steering wheels | polyester, UV-resistant | tex 90–210 |
| Boats, campervans, garden furniture | UV-stabilised polyester or PTFE | tex 70–135 |
| Awnings and canopies | UV-stabilised polyester or PTFE | tex 70–135 |
The table is for initial guidance. The final decision is always made after a test seam on the actual material.
Upholstery thread thickness and needle
The thicker the thread, the larger the needle must be. The eye of the needle must let the thread pass freely, and the groove along its length must accommodate it completely. If the needle is too small, the thread rubs, heats up and breaks. If it is too large, an ugly hole remains, especially in leather and vinyl. Needles with a cutting point are used for leather, and needles with a round point for fabric.
Colours and batches
On furniture and cars, the thread almost always has to match the colour of the material or be deliberately contrasting. Upholstery workshops usually keep a basic range – black, graphite, grey, beige, brown, white – and order special colours to a sample. If one product will be sewn from several cones, check that they are from the same batch, otherwise the difference in shade may be visible on two adjacent panels.
The most common seams in upholstery
- Lockstitch – the main seam for joining panels and for decorative lines. Strong, and it does not unravel if one stitch breaks.
- Piping seam – piping sewn between two panels. It requires a special foot and a thread that withstands bending along the edge.
- Double parallel seam – for visible seams on seats and sofas, sewn with a twin-needle machine.
- Zigzag – for joining pads and linings where elasticity is needed.
For each of these seams it is important that the needle and bobbin threads are compatible in material and thickness. The bobbin thread can be slightly thinner, but it should not be of a different material, because the two threads will age and shrink differently.
Tips for the upholstery workshop
- Separate threads by purpose: for inner seams, for visible seams and for outdoor products.
- Use a stand above the machine and cones so that the thread unwinds without twisting.
- Change needles regularly – a blunt needle tears the filaments of the thread and the material.
- Store threads away from the sun and heaters.
- Keep a sample of every colour used, with the article number, for future repairs.
Upholstery threads for cars and boats
Automotive and marine upholstery are the most demanding areas. There, threads must withstand friction, heat, moisture and sun all at once. For these products, see our selection of threads for the automotive industry. For leather goods such as bags and belts, you will also find our threads for footwear and leather useful.
Upholstery threads wholesale from Polkom
Polkom is a Bulgarian manufacturer and wholesaler of sewing accessories based in Sofia with over three decades of experience. We supply upholstery threads to furniture and automotive workshops and to boat and campervan ateliers, match colours to your sample and send samples. Minimum quantities depend on the article. Contact us via our inquiry form with the material, product and colours you need.
