Marine Thread: The “Glue” That Holds it All Together

Click to buy marine thread

Marine thread is the glue of boat canvas. Be sure you know the basics. After fabric, thread is the most important component of your boat canvas.

Many boaters believe that marine thread should last forever. After all, it's outdoor thread, right? Well, there actually is one type of outdoor thread that does last forever or outlasts your boat canvas. It's thread, made with PTFE or Polytetrafluoroethylene, which is really Teflon®. This type of thread can be exposed to sun, salt, chemicals, pollution, it doesn't matter. It will last and last.  This super resistant to chemicals thread doesn't mean the thread can't break, it just means that it won't break due to exposure breakdown.

Gortex® is associated with the brand name Tenara®, the first PTFE thread of its kind to hit the market. In the beginning, it was a flat fiber that most sewing machines could not accommodate. Over the years, they modified their process and came out with a twist thread that could be used with most sewing machines. Colors include, black, white and clear and now several colors have hit the market.

The reason you don't see PTFE threads being used in all marine canvas shops is the price. At $160.00 per 1-pound spool, it's simply not offered by all fabricators. Besides Tenara's® Gortex®, Solarfix® PTFE, has made a big competitive splash in the market and is what I am using.

Thanks to PTFE thread, canvas boat covers can finally be made with the quality they deserve.

So what about the rest of the outdoor threads on the market?

Polyester or polyester dacron is the most common marine thread you will find in canvas shops. They are UV resistant and some are anti-wick which means that the thread has a lubricant that repels water and keeps the water from traveling down the thread and into the needle hole. This helps to keep the water from seeping through. These threads are considered chemical and heat resistant, but eventually weaken in the sun.

The most important factor in keeping water from seeping through the holes is using the correct size needle with the right thread.  Overly large needles will poke holes water can get through.  

Two common sizes used on boats are 92 and 138. Having used both, I can speak from experience and say without a doubt that 138 will outlast 92. So if you have a choice, go with the heavier thread.

Some marine thread brand names used on boat covers include the following:

  • Sunguard®
  • Sunstop®
  • Star Ultra Dee®
  • Aqualon®
  • Dabond®

All of the above come in many colors. For the DIY stitcher ready to sew your own project, you can buy 4 oz spools in 92 and Solarfix® 2000 in small spools with about 330 yards. Your home sewing machine should be able to sew with 92 with no problem and also the Solarfix® 2000, but very unlikely that you can sew with the 138.  

Solarfix® also has a single strand 1360 which I have been assured works very well on home sewing machines.

The next size down from size 92, is 69 and your home sewing machine will definitely be able to sew with it, but it won't hold up in the sun. In the south, you would be lucky to get a year out of size 69. If you use this size, plan on frequent restitching.

Marine Polyester Thread

Marine Thread 92 - 4 oz

View White/Black Thread in Store

Marine Thread 138 - 16 oz

View White/Black Thread in Store

We are proud to offer lifetime Solarfix® 2000 Thread - Although we can't guarantee this marine thread will sew on your home sewing machine, it does sew nicely on our early model Kenmore and Bernina and industrial machines.

I have been told that computerized sewing machines struggle with PTFE threads.

View White/Black Solarfix® 2000 Thread in Store

View Thread Cone Holder for Marine Thread
in Store

Lastly, I will mention what NOT to use as a marine thread!

Nylon thread. Nylon is a bad choice for outdoor thread. Be careful when you have your custom cover made. Be sure to ask what type of thread they will be using. We restitch plenty of covers that have been sewn with nylon. This happens frequently with auto trim shops and home furniture upholstery shops. Sometimes they just don't know any better. For more on canvas boat cover repair check out our web page all about boat cover repair.

To sum up this discussion on marine thread: If you can have your cover stitched in PTFE thread, do it. You won't be sorry!

Be Sure to Check Out EZ-Xtend Boat Zippers!

EZ-Xtend Boat Zippers
EZ-Xtend Boat Track
EZ-Xtend Drip Shields

Procceds from the EZ-Xtend Boat Zipper website helps support

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A Christian based children's home for boys and girls in crisis and in need of hope and healing.


Fantastic Results

"I wanted to thank you for the fantastic results I have with the EZ-Xtend zipper solution you provided for my Sea Ray.

The isinglass had shrunk to the point that installing it was an all-morning job, with some snaps totally unusable due to the material shrinkage. I really was preparing to purchase a complete new canvas set, but hated to spend the money-especially since the canvas is still in excellent shape.

The EZ-Xtend zippers have made the canvas/isinglass installation and removal about a 10 minute job! (and looks great too!) Thanks again for the quick solution and the reasonable cost, I really do appreciate it.
Steve Donovan

The Bottom Line

The extend zippers have been a resounding success. Zippers were needed for the starboard stern section of my bimini top, and for both side curtains of my camper canvas. It is a clever design you came up with to increase the width of connectivity between my bimini top and camper canvas sections. I do not know what I would have done otherwise as the camper canvas sections have shown shrinkage over time.
M. Marien

Such a Great Idea

I got a chance to install these yesterday and just thought I'd get back to you to let you know that they worked perfectly for me. I couldn't be happier with that simple to install solution to my problem now allowing me to properly and fully enclose my cockpit again. Such a great idea.
J. Reed
British Columbia

Easy to Install

The Ez-xtend zippers were very easy to install---especially with a little lubricant ( which I always apply periodically to zippers)
New Jersey

Rare Traits

"True skill and craftsmanship are rare traits in today's society. When they're held by a person that truly cares about her customers, brings honesty, creativity and passion to her work, you have just described Tammy Hampton. Better known as "The Cover Girl," Tammy has been both a friend, mentor and business partner for nearly twenty years.

I found Tammy by her name tag.... sewn to a sailboat cover, in a nearby marina. The boat cover was fitted with such precision, it clearly stood out from the others. In the years since, Tammy has 'dressed out' at least twenty boats for me. She has yet to meet a challenge for which she could not find a creative and effective solution.

Tammy has become a valuable resource to my Boatbutler business, and she has actually created sort of a "cult" following among my customers. Once they see the quality of her work, the choice is an easy one.

I am still grateful for that little tag on that sailboat cover I found nearly twenty years ago."

Steve Hammond
Owner, Boatbutler Marine Services, Inc.
Alpharetta, Georgia

Brilliant and Simple Solution

WOW!  I just got the EZ-Xtend Boat Zippers for my canvas and what a simple solution! Thank you for coming up with this.  I am telling my friends about this product.

Susan M. 

You Made Everything Easy

We just installed the zipper we received on our sea ray boat canvas- what an incredibly easy experience!  It makes snapping the canvas so much easier with the zipper extension.  Thanks for the crimper & tape - you made everything easy.  We just ordered 5 more longer ones to completely update our canvas.  Thank you so much for your quick response on our first order. 


Love Your Website

I love your website and wish we lived closer, so that I
could stop by your shop - sounds like a wonderful place!
Judy D
Winchester, TN

Made our boating season very enjoyable!

Our boat was 10 years old when we purchased it and the canvas was stored all rolled up in the boat.   When we tried to put the canvas together the force required to zipper the canvas together was making the canvas split on the seams or causing the zippers to tear, so we had to leave parts of the canvas unattached and every time it rained we would get water in the boat.  With your zippers in place we could button up all of the canvas and make a very nice weather tight space which made our boating season very enjoyable.

Phil R.

EZ-Xtend Zipper Saved the Day 

I purchased a used 27' Sundancer about a year ago.
I came with the Bimini, side curtains & windshield eisenglass panels along with a bimini to transom cover with eisenglass also.
I don't think the original owner ever put anything up except the bimini.
Nothing would fit, ever where it was short. 
If I cheated and put the windshield panels in the side curtains were never even close. If I did it the other way, sides first front panels were off. The canvas is hi quality material from a well known manufacturer.
Started researching about what to do. Then I came across a blog on the Searay owners site. One of the chats was about what I had going on. One owner who replied had purchased your zippers and was raving about solving his problem using them.
Well I'm here to "RAVE" about them also. My $300.00 investment with you has saved me thousands in replacing what is perfectly good canvas.
Boaters if you have a shrinkage problem and we're not talking the George Costanza kind this is your answer.
Your site has also grown to include more helpful information on boat care and maintenance. Great information and wonderful tips.
Thanks again Ron W.