Sail repairs....suitable needles/thread

[David Geiss]

Hoping that there are some on the forum who sew with a machine.
I have a Juki straight stitch machine........it's great for nearly everything I have done with it.

Today needed to slightly modify an ACA lateen for a canoe.
The polyester thread abraded constantly from the needle side (the bobbin side appeared to be fine). The plies of the thread from the needle constantly bunched up on me as it's fed through the needle. Result is breakage and need to re-thread constantly.

For going through 2 or layers of sail cloth, is there a thread/needle combination that I should be using?

Any suggestions most welcome!

Best,
David

[John E Hardiman]

What type of needle are you using? There are special machine needles for for "hard" fabric and leather that have a gullet for the thread so it won't catch on the fabric and a broader point.

Also, normal polyester thread for fabric is not the right choice. It most likely has been mercerized. You need a nylon thread with a "hard", "glazed", or waxed finish.

[David Geiss]

Hi John:

Thanks...the needle is right...has the gullet you mention and I have it facing the right way for the thread feed.

I was not aware of the distinction in threads. Really appreciate that.
Any favorite brands/ mail order sources of thread?

On second thought. I might use a bigger needle...any thoughts on needle size and thread diameter?

Thanks again.

Best,
David

[Todd Bradshaw]

No, you don't use nylon thread on sails and you don't use waxed thread in a sewing machine unless you like frequently having to take the bobbin race all apart and clean the waxy mess out of it. Proper sail thread is polyester. On a really high speed machine it can be dipped in a silicone thread lube or lubed with an onboard gizmo that has a reservoir and a couple of saturated fuzzy pads that the thread is fed through on the way to the needle, but that's it for thread treatments. Hemingway and Bartlett Dabond D tends to be one of the most common and best sail threads if you can find some (Sailrite sells it if you can't find it elsewhere).

A 44 sq. ft. lateen like you are sewing should be sewn with either V46 or V69 thread and a number 16 or number 18 needle. Point type doesn't matter much as any decent machine should be able to punch through multiple layers of that cloth with no problem. Fabric store polyester thread would also fall into that general thread size range and work OK as well, though cheap thread is no value, so stay away from the bargain bin.

If you're getting blobs of fuzz forming up top you have a sewing machine problem. Light, hard-finished fabrics with little give and where the stitches can't bury down in the cloth will tend to make such problems more obvious.
My guess would be that either there is something wrong with the timing or with the clearance between the hook (probably a rotary one on a Juki) which goes around the bobbin cage and the needle. Instead of just almost hitting the back of the needle as it goes past it to catch the top thread and spin it around the bobbin, the point of the hook is actually hitting the thread, piercing the thread and shredding it.

This type of thing can also be caused by more simple problems, like a bad needle where the eye wasn't properly deburred or even a needle that's not installed with it's eye pointing the proper direction. Once in a while you can actually cure the problem by turning the needle so that the eye points slightly off to one side or the other. If it's already been problematic with various needles though, something needs to be readjusted to keep the hook from shredding the thread.

Pop the plate off so that you can watch the needle and rotary hook in action as you turn the machine over by hand. At or very near the bottom of the needle stroke, as the needle starts back up, the hook should pass as close as possible to the back of the needle (without hitting it) just above it's eye and cleanly pick up the top thread to start spinning it around the bobbin. Getting this clearance and timing set right is probably the most important adjustment (and sometimes the most tedious one) on a sewing machine. The adjustment itself is usually made by slightly changing the position of the bobbin cage/hook assembly on it's shaft - both it's fore and aft position on the shaft (for needle clearance) and it's "round and round" position for timing, so that the hook gets to the needle at the right time in it's stroke. This can be an all-day adjustment session if you don't know what you're doing, so if a needle and thread change doesn't fix the problem, you might want to see about finding a repair shop or switching machines for now. Any good home machine should sew that sail and will also probably have a zig-zag stitch, which is better for sails. If you do use a straight stitch, make it a fairly long one (3-4 mm) because short stitches tend to make a perforated line across the sail that says "tear here".

[John E Hardiman]

Listen to Todd, I was hoping he would show up..:)

But Todd, I have had problems when sewing some fabrics like canvas and coated fabrics of fraying or stripping off the outer fibers of the thread. At first I moved up in needle size and checked the guides and the needle plate, and it would sew other fabrics/leather just fine. I thought about an adjustment or feed problem, but all that seemed fine. I finally moved to hard finished thread (sometimes called button, carpet, or waxed quilting and no, it doesn't shed wax like hand sewing waxed thread), not mercerized or wrapped, and the problem went away. Most of those threads were cotton or twisted nylon as I couldn't find any poly in a hard coating.

[David Geiss]

Todd:

I really appreciate that you took the time to enlighten me and, hopefully others. There is a lot of information there so I will pint out, review and spend an afternoon with my machine.

First will get some new needles and then start from scratch. The thread is fraying as it arrives inbound to the needle, not from below once it id picked by the bobbin. Slower speed helps but the fraying still occurs.

So again thanks and I'll get to the bottom of it. I imagine that learning how to make the timing adjustment is a worthy investment of time for when I relocate to the hinterlands and no nearby shop is around.

I have considered a zig zag machine but most of what I do is repairs and canvas work so the straight stitch is fine.

BTW, I have a nice old Singer straight sticth that I offered on the forum (free) some time ago and a fellow from CT, Ray Connors, was going to take it but I think he now has other plans.

I can't offer a table/motor but the Singer head is for the asking.....


Best,
David

[Todd Bradshaw]

It's hard to be too specific without having an exact thread/cloth/machine to deal with, but in general, nylon has a shorter U.V life than polyester (Dacron is polyester). Nylon may have more tear strength due to it's slightly more stretchy nature, but sunlight seems to be a bugaboo in almost everything we work with in boating, so U.V. life is always a big deal. If you're sewing the buckle on the seat belt in my car, I'd prefer you use nylon thread, since it has a better chance of surviving a sudden, intense strain, but for most other stuff, polyester is the way to go. Cotton actually has good U.V. life, but it's weaker than synthetics, shrinks over time, shrinks and/or stretches when wet and is prone to mildew with more than just cosmetic damage possible. Polyester-cored, cotton wrapped thread (like Coats and Clark "Dual Duty") has the strength of the polyester core, combined with the feel and more importantly, the wicking ability of the cotton outer part. It is common on outerwear as the cotton swells a bit when it gets wet and helps plug the needle holes and prevent seam leakage.

Any time you get thread fuzzing it's almost always either bad thread (or wrong thread), a bad needle or a mechanical misalignment. Unfortunately, the last one is a very big category with lots of potential options. With the number of things that have to happen and little gizmos that have to move precicely every time a machine sews a stitch, I'm still amazed that sewing machines work at all!

Switching to a fresh needle is the easiest first check. For home machines, you might want to try "ball-point" needles which punch a slightly over-sized hole with their tips and then taper a bit. On tough materials they can sometimes take strain off of the thread by making it's passage easier. It's kind of like sewing leather. It looks tough, feels tough and it's thickness can be a problem for the stitch timing, but once the needle punches through it, the rest is easy. Sewing heavy fabric is different because the yarns tend to part temporarily for the needle, but most don't break and they immediately start coming back together as the thread is being pulled through the hole. The ball-point needle blasts a bigger hole in the cloth and eases the thread passage.

Next is the thread. It might be worth ordering a couple small, one-ounce or four-ounce cones of Dabond or other really good polyester thread. If your machine seems to need a more coated variety, they make an anti-wick form of Dabond that's commonly used on boat covers and similar stuff, but which will also work for general sewing. It has a little bit stiffer, slicker nature than the regular Dabond. In any case, switching to the best thread you can buy is pretty cheap compared to spending hours fiddling with a tempermental machine and this should take the thread out of the problem equation.

Im trying to think of something similar to thread lube, but locally available. One possibility is Armorall. You take a small pad made from soft, folded-up fabric, soak it with Armorall and stick it to the machine with anything from a clothespin to a hunk of duct tape. Position it along the thread path as it winds around the gizmos on the machine and just let the thread rub against the saturated pad as it goes by. With good thread, you shouldn't need to do this, but if after all those steps you're still getting fuzzing or abrasion on the thread as you sew, then it has to be a mechanical or machine adjustment problem.

I suppose that we also should note that every machine has limits, as far as how heavy you can go, material-wise and still get decent stitches. There are three things to consider: First, the obvious one, which is "how much stuff does my machine have the power to punch a hole through before it jams, breaks needles or just stops cold?" The second one is "how much thickness can I sew through and complete the stitch before the feeding mechanism starts to move the fabric forward for the next stitch?" There comes a point, thickness-wise, where the machine starts to move the fabric before the tip of the needle has cleared the surface of something thick - and at that point the needle usually breaks or bends.

When you finish a line of stitching, you raise the presser foot to remove the fabric from the machine. As you raise the foot, a little set of links push a tiny pin, inside the machine, and this releases the top tension device. This makes it easier to pull some slack in the thread and get the item out of the machine. #3 is that at some point, thick material will push the presser foot high enough above the base plate that it starts to engage the little links and the tension adjustment goes down the tubes, taking stitch quality with it and potentially causing all kinds of foul-ups.

So every machine is going to have a limit to how thick and/or heavy you can go. Either lack of punching power, needles tripping because the fabric advances before they're clear or the tension going south because the foot is too high will set the limit for that particular machine. These kinds of problems and any others which can throw of the timing of all those little spinning parts working together inside the head can cause thread abrasion and fuzzing in addition to the simple stuff like needle problems and thread quality.

[raycon]

Great thread ...pun intended!
David I'd still be interested in the machine but I see little chance of me freeing my schedule to head down your way.
I'm going to print this thread as well -- Thanks for the effort Todd.

David I have more walnut if you're still looking. 8/4,7/4,5/4 up to 24" wide 10' in length. I'm close to Mystic Seaport stop in if you're in the area.

Ray

[Richard Smith]

Sometimes the most obvious is the solution. Have you tried adjusting the top thread tension - looser - or checking to be sure it is getting a nice loose feed before arriving at the tension devise? It could be that the top and bottom tensions are way too high.

[Bruce Hooke]

To add to Todd's great post, one other limitation I've run into on my home sewing machine (which is a tough old Singer that will punch through a lot) is if I try to run thread that is too heavy through the machine, it just won't go. The bobbin end is usually where I have problems -- I think the spaces the thread has to move through in this area are simply not big enough to allow heavy duty thread to get through.

[CAPNBIL]

I found, in stitching sailcloth, that an occasional shot of silicone lubricant from an aerosol can, on the thread cone or spool, helped reduce fraying of the thread going through the needle.

[David Geiss]

Hi All:

Great additional posts...thanks! I did at one point have some of those "ball point" needles....time to restock with thread and new needles. Think that I'll get it in order.

Todd.....thanks for the heads up on Dabond. I'll try it.

My last repair to the ACA lateen came out decently and it sailed well this past weekend anyway.

Ray...I missed the Gardner Small Craft meeting but am thinking of a ride up to the Tiverton area pretty soon. Are you around most of the summer? I could put the Singer war horse in my petro-chariot........