By Seamline workshop, marine upholstery team. Updated September 27, 2026
Polyester is the common outdoor thread, but it loses much of its strength after long sun exposure and its color fades toward white. PTFE lifetime threads such as Gore Tenara resist UV, salt water and cleaning chemicals, and Gore guarantees Tenara to outlast the fabric it is sewn into.
What it is
What lifetime thread is
01Polyester loses much of its strength after long sun exposure
02Gore builds UV resistance into the Tenara ePTFE fiber, not a coating
03Gore guarantees Tenara to outlast the fabric it is sewn into
Colors
Tenara thread colors
Gore's color card for Tenara, pigmented thread that holds its color.
2Enclosure PTFE thread only, per a Strataglass fabricator
3Boat cover PTFE thread
4Seats UV-treated polyester with some give
Side by side
Three threads
1
UV-treated polyester
Loses strength over long exposure, fades
2
PTFE lifetime
Unaffected by UV, per the makers
3
Nylon
Less UV resistance than polyester, indoor upholstery
Stitching
Stitch patterns on seats
Diamond
Quilted diamonds, the classic helm and bench look
Channel
Straight channels, clean on sunpads and settees
Hex
Hexagon quilting for a custom look
Up close
Thread up close
PTFE seam on navy canvas
Thread cones in four colors
A spool of PTFE beside a double-needle seam
How long polyester thread lasts in the sun
Thread makers do not put a number of years on polyester outdoors, because it varies with exposure. Polyester resists UV better than nylon but loses much of its strength after prolonged sunlight, so UV-treated polyester is the pick for outdoor cushions and covers.
What lifetime thread is
Gore makes Tenara from ePTFE fiber and says its UV resistance is built into the fiber, not a coating. Gore adds that Tenara is unaffected by acids, bleach and cleaning chemicals and uses non-fading pigments.
Gore guarantees Tenara to outlast the fabric, and other PTFE lifetime threads carry the same kind of guarantee. A fabricator quoted by Strataglass sews clear enclosures with PTFE thread only.
Why not use it everywhere
Lifetime thread costs more and is trickier to sew. Tenara runs best on rotary hook machines because of its wax finish. Upholstery seams need thread with some give, so seat work often runs UV-treated polyester, with PTFE on exposed seams.
Thread types compared
Thread
In the sun
Fits
UV-treated polyester
Loses strength over long exposure, fades
Cushions, covers, shaded seams
PTFE lifetime
Unaffected by UV, per the makers
Biminis, enclosures, covers
Nylon
Less UV resistance than polyester
Indoor upholstery
What we use and why
PTFE thread on biminis, enclosures and covers that live in the sun
UV-treated thread on seats where seams need some give
Thread color matched to the canvas, since pigmented PTFE holds color
Questions
Questions boat owners ask
What kind of thread is used for boat upholstery?
UV-treated polyester is the common outdoor thread. PTFE lifetime thread such as Tenara is used where seams sit in full sun, like tops and enclosures.
Is Tenara thread worth it?
On canvas that lives outside, it often is, since a restitch costs more than the thread. Gore guarantees Tenara to outlast the fabric it is sewn into.
Does lifetime thread mean the canvas lasts forever?
No. The guarantee covers the thread. Fabric, zippers and clear panels still wear with sun and use.
Next step
Get a quote
Send a photo of the failing seam. We tell you if a restitch will hold.
