Simthread Upholstery Repair Thread 12WT 229 m — Bonded Polyester, UV-Resistant Heavy-Duty

Simthread Strong Upholstery Repair Thread is a bonded 12WT polyester sewing thread made for heavy-duty indoor and outdoor repairs, offering UV resistance and smooth, lint-free performance for hand or machine use.

Designed for demanding upholstery, marine, and outdoor textile projects, this bonded polyester thread blends tensile strength with weather-resistant finishing so seams hold up under sun, wind, and frequent use. Each 250-yard snap spool is manufactured with a tight filament structure and bonding process that reduces fray, eliminates joints, and feeds cleanly through needles and machine tensioners. Simthread’s formulation aims to give professional results when repairing furniture, cushions, awnings, sails, or automotive interiors.

How strong and weather-resistant is this thread?

The thread is a 12-weight bonded polyester (finished TEX 90), engineered to resist UV-related strength loss better than standard polyester filament threads. Bonding and filament construction increase abrasion resistance and reduce linting for longer-lasting seams exposed to the elements.

• Finished size: 12WT (TEX 90) with raw filament TEX 69 before processing
• Engineered bonding reduces breakage and fraying
• Improved UV resistance and colorfastness for outdoor exposure
• Lint-free and joint-free for consistent sewing performance

Can I use it with home sewing machines and hand-sewing?

Yes — Simthread 12WT is compatible with most domestic and industrial machines when paired with machine needles size 16 or 18. Hand sewing also works well using the recommended hand needle sizes to match the thread thickness.

• Recommended machine needle sizes: 16 or 18
• Recommended hand needles: sizes 1–5 for easier passage through heavy fabric
• 250-yard snap spool format fits many thread holders and storage setups
• No joints or loose fibres means fewer skipped stitches and jams

What projects is this thread best suited for?

This heavy-duty thread is formulated for robust textiles where seam strength and weather resistance matter, such as outdoor cushions, grill covers, awnings, tents, sails, and automotive upholstering. It performs well on both natural and synthetic heavy fabrics including canvas, vinyl, Sunbrella-type materials, and heavy woven upholstery fabrics.

• Patio and outdoor furniture cushions, pillows, and covers
• Awnings, sails, tents, and marine upholstery
• Automotive and RV seat repairs and trim work
• Canvas work and heavy-duty upholstery repairs

What comes in the package and colour options?

Each product listing represents a single 250-yard snap spool sold individually; kits with multiple colours are available separately. Spools are offered in a range of colours to match common upholstery shades, and some sets include sewing needles and a seam ripper when sold as a kit.

• Single spool: 250 yards per snap spool
• Sold colour-by-colour; some multi-colour kits include needles and a seam ripper
• Eight colour options commonly offered for matching upholstery tones
• Colours are treated for UV resistance and colorfastness

Who is this product for? Simthread Strong Upholstery Repair Thread is aimed at DIYers, professional upholsterers, marine technicians, and outdoor gear repairers who need a durable, weather-ready thread for heavy fabrics. If you work on patio furniture, automotive interiors, sails, tents, or any project exposed to sun and abrasion, this bonded 12WT polyester spool provides a reliable, low-lint option that feeds smoothly through machines and hand needles alike.