Sewing Test Results

[wbuford22]

Investigating the art of the possible, I ran some 7.4 oz Dacron sailcloth through my trusty Singer 4432. The thread size is V92, needle is a Singer universal size 110/18. Messed around a bit with stitch width and length, including a couple of lines of the triple-stitch zig-zag. I intend to try a similar test with V69 thread.

Although the machine seems to have sufficient power to get through the material, not sure about thread tension, and would much appreciate anyone with more experience weighing in on how it looks, particularly on the reverse side.

Bottom line I think is that sail construction with this machine seems feasible.

MultiLayer.jpgobverse stitching.jpgreverse stitching.jpg

[pez_leon]

While we wait for the more knowledgeable to chime in (what's the Todd Bradshaw version of the Bat Signal?) I can tell you that your reverse side shows you either need more upper tension or less lower tension. It's hard to get stitches to bury in sailcloth but I think your machine can probably do better.

- James

[Todd Bradshaw]

My take on it is that you need a bit more top tension to pull the knot closer to the surface, and more bottom tension as well. Those curved stitches on the back side and the stitches far enough above the Dacron to cast shadows below them would benefit and tighten up with more tension. V-92 is rather heavy for panel seaming. The biggest drawback is going to be the fact that bobbins don't hold very much of it, and it gets annoying having to fill/switch them so often. If your seams are tape-basted before stitching (which they should be as it adds tremendous seam strength) then V-69 is probably quite adequate. The needle blasting through and leaving rather ugly holes on the back side is typical and just something you live with. Triple-stitch zig zag will work if the machine can make it big enough. For sails it needs to make a pattern nearly 1/2" wide. It is faster, as you only make one pass, but it doesn't tack down the edges of the cloth, so you may get more raveling.

Sewing two lines of perfectly parallel zig-zags from an uncomfortable position and on a big unwieldly mass of fabric can be a real bear. If the thread color contrasts with the cloth, then any variation from parallel can stand out like a sore thumb and look ugly. If you choose to use dark brown thread on white Dacron be aware that you will really have to feed the cloth through the machine nearly perfectly or the variation from parallel stitch lines will look pretty bad. One way to hide this if you still want to have some color contrast is to use two different thread colors, avoiding two lines of the same color right next to each other. Variations from the two stitch lines being perfectly parallel will pretty much disappear.

010.jpg

[wizbang 13]

Yup , too much on top and/or too little on bottom.
Tune that bobbin and case UP! Not a speck of rust or dust.
When the top thread starts to fag,I put some lube on a cloth that the top thread passes over , sillycone spray usually.
Whats the best needle Todd?

[Todd Bradshaw]

#16 or #18 are pretty typical for general sail use using V-69 thread. You can also use a #18 for most V-92 thread, but some of it will sew better with something in the #21 range. Some folks tape a pad of cloth to the machine which has been saturated with silicone or Clearco thread lube and let the thread lightly drag across it. If you use the combination of basting tape and thread lube you may notice small greasy spots at the needle holes, where the adhesive and lube are reacting to each other. These, like you can see here on the tanbark sail, will usually fade away within a couple of months.

corner-detail-4.jpg

[Nicholas Carey]

Investigating the art of the possible, I ran some 7.4 oz Dacron sailcloth through my trusty Singer 4432. The thread size is V92, needle is a Singer universal size 110/18. Messed around a bit with stitch width and length, including a couple of lines of the triple-stitch zig-zag. I intend to try a similar test with V69 thread.

Sail-Rite recommends not using any thread heavier than V-69 in a home machine, but you probably get away with V-92 thread if you're using a PTFE (Teflon) thread like Tenara:

https://www.sailrite.com/PDF/Thread%...mendations.pdf

Needle size is/should be based [largely] on the thread you're using, not the fabric: the thread has to fit the needle's groove and eye or you're not going to get good stitches.

This commercial sewing machine dealer says that with V-92 thread, you want to use a 19/120 needle, and with V-69 thread, a 16/100 or 18/110 needle.

https://www.tolindsewmach.com/thread-chart.html

And the general take is that when sewing with heavy thread and heavy fabrics, you'll need to adjust the tension, probably easing off on the bottom tension.

[wbuford22]

Thanks to all for the feedback. I will see what can be done with adjusting the tension and thread lubrication. Are there recommendations for type of needle in addition to size? Basic sharps seem to be what comes up in various places I have looked.

I'm doing this line of experimentation looking towards replacing the 244 sq ft mainsail of my 30 foot Alden Priscilla, so any relevant feedback for material selection/methodology would also be appreciated.

[Todd Bradshaw]

probably easing off on the bottom tension.

The bottom tension is already too loose on the samples provided. Unlike top tension which is made by pulling the thread between two spring-loaded disks, bottom tension adjustments are kind of crude and can take some time to get dialed in properly. The adjustment is a small screw on the bobbin case. The thread passes under a metal tongue as it exits the case, and the screw adjusts how firmly the tongue presses on the exiting thread. That pressure is all that there is to create the bottom tension. There is a second, slightly smaller screw behind the tension screw and all it does is hold the tongue to the case. When making adjustments, you generally turn the adjusting screw maybe one quarter turn or less, then test the stitch, adjusting the top tension as needed to generate a neat stitch which is down tight to the cloth. Usually when adjusted properly the bobbin thread will pull out smoothly, but fairly firmly and having too much or too little tension is undesirable.

bobbin.jpg

I generally use Dabond polyester thread and Groz-Beckert needles and have since 1980 when I started working on balloons without any problems. The needles have round shafts, where a lot of home machine needles are flat on one side. Sometimes you can get a lot of sewing supplies and sewing machine parts off of eBay that fit a variety of older machines. Building a 244 sq. ft. sail your biggest hassle is going to be just handling that much weight and bulk. You can't wad it up and you can't have it hanging off of the table as you sew, meaning that it needs to slide on the floor. Fabric-wise, there is a grade of fabric called OEM or something similar which will be substantially cheaper than the other offerings in most weights. It is basically junk and gets its bias stability from resin coating alone. After a couple of years, the resin breaks down and the sail loses its shape. If you are going to put in the effort to make the sail, use high quality cloth, which derives much of its stability from the weaving, not just the resin. It will last and work better. At that size, you want to be able to sew through probably five layers of cloth and seam basting tape cleanly.

[wbuford22]

Thanks to all for the knowledge. The internet provided the service manual for my machine, and I increased the tension for both bobbin and needle, and tried again with V69 thread with a 100/16 needle. (Green thread is needle side, red is bobbin side). It seems to work better, looking more or less balanced towards the end of the test runs, but the last bit of triple-stitch zig-zag seem to be working the best so far. Not sure any top thread lubrication is indicated as it seems to be dragged through the cloth just fine, a little too much even. Taking a break to post some progress photos, I'll reattack after some sleep. I think I'm inching towards something satisfactory, and once again, any and all feedback is welcomed.

Any thoughts on whether V69 thread would be sufficient for my needs, with 2 or 3 lines of stitching, vs trying to make the V92 work? Or if it works, is triple-stitch the way to go?

IMG_8007.jpgIMG_8008.jpgIMG_8009.jpgIMG_8010.jpg

[Nicholas Carey]

For ordinary fabrics, a good way to verify that you have top and bottom tensions matched and balanced stitching is to cut a square of fabric, and run a line of straight stitching across it on the bias. Do not backstitch either end as you would normally.

Take the seam ends and pull them until the thread breaks. If the stitches are balanced both top and bottom threads should break. If only one breaks, it's an indication that it's tension is too tight, or the other thread's tension is too low.

Might not work with sailcloth, as it's specifically designed to reduce bias stretch.

Here's another way of testing for balanced stitches, but it also depends on bias stretch.

https://fcs-hes.ca.uky.edu/sites/fcs...ct-mmb-213.pdf

But it also has a sketch of what a properly balanced stitch should look like: if you seam up two layers of fabric with top and bottom tension in balance, the "lock" between top and bottom threads should be buried in the center of the two fabric layers.

[Todd Bradshaw]

You aren't likely to bury the intersection of the top and bottom threads in the cloth on most Dacron. It's too firm. The best you can hope for is to get them very close to the hole, but they probably won't be down in in the needle holes. Other than on spinnaker fabric the typical home machine triple stitch is too small to work well on Dacron. The needle holes are too close together and the stitches are too short.

The reason we use a zig-zag on Dacron is that it spaces the needle holes pretty far apart for more strength. Part of this is due to the stretch resistant nature of Dacron fibers and the fabric woven from them. It tends to be prone to something called "explosive tearing". When you have some sort of tear or flaw in Dacron sailcloth (including a needle hole) and you apply stress to it, essentially the yarn nearest the hole takes the majority of the stress, until it can't take any more and that yarn breaks. Then the force is taken by the second yarn, until it breaks, followed by the third, fourth, fifth, etc. It is why you can take a heavy piece of sailcloth, start a small cut in one edge, grab it on either side of the cut and easily tear it in half. Nylon, with its increased stretch doesn't do this. The stretch allows the yarns to help each other out, spreading the stress over a larger area and a lot of yarns. For most sails we need that low stretch of Dacron to make stable sails which hold their designed shapes and spacing the needle holes out with a zig-zag tends to make the strongest seams. A triple stitch must be a really big one to work at all, and there is no question that two lines of regular zig-zag makes a stronger seam. However, it takes two passes through the machine, so budget sails are cheaper to build with a big triple stitched single pass.

[Lemsteraak]

Sewing Machines are right up there with Bicycles and Sailboats as one of the best inventions in my mind. I think older "home" machines are capable of much more that we give them credit for. I have an old Pfaff and I've noticed that zig-zags will not be as even as it works through more layers so I would vote not to use contrasting colors. Your Singer seems to handle zig-zags better though

I have a small walking foot portable sewing machine and while it has a lot of power it isn't as well crafted or have the precision of an old Singer

[Todd Bradshaw]

Any machine will have a limit to how much thickness it will sew. As you raise the presser foot, at some point it will automatically begin to release the upper tension disks. If it is in the process of making a stitch at the time it starts to release the tension that will be a bad thing which messes up the stitch. Home machines generally reach that thickness limit earlier than industrial machines do and that may be the thing which establishes their limit of workability, despite still being able to punch through multiple layers.

[wbuford22]

Are there any objective measures for how close is too close together for stitches? The machine seems to struggle a bit as I get to the longest stitch width/length (ie, so many mm between)? In the same vein, any thoughts on the decision point for when to trade up to three lines of stitching vs two, or two lines of V92 vs three of V69?

[Todd Bradshaw]

No established guidelines that I am aware of. Three lines of stitching is rare and when used it is generally done on seams with an overlap in the 3/4" or better range. I can't really imagine sewing seams with V92 thread. To start with, unless your machine has huge bobbins, you are going to be constantly running out of bobbin thread. Secondly, it is heavier than the job calls for, plus if you are tape-basting your seams (which you should be for both convenience and strength) the tape will be doing most of the work and the stitching is there as back-up and to hold the edges of the panels down.

[wbuford22]

Tape basting is the plan. Would V92 be called for for corner patches? Or would two lines of V69 work there too? Again, looking at a 240 sq ft mainsail.

And thanks again for the all the information.

[Todd Bradshaw]

There really is no need for anything sewn with V-92 on that sail. Tape basting combined with one line of V-69 is plenty for corner patches.

[Todd Bradshaw]

Standard procedure, by the way, for corner patches is to place them on the sail starting with the smallest one and ending with the largest one on top. Most of the time it's a good idea to take a pencil and hold the corner up to a light source so that you can trace the edges of the patches under the top one onto that top patch. That way you know where to sew to catch them even if you can't see them through the stack. Most of these small sails were sewn with V-46 thread, which is plenty and yields best bobbin yardage. The patches can be round, triangular, square or traditional tongue patches and their weave should match the sail panel's weave direction. One of my pet peeves is seeing vertical or cross-cut sails with radial corner patches - fanning out a bunch of cloth strips to make the patch. They look sexy and are easy to make (one reason they are popular at big production lofts) but most of the weave is going the wrong way and it tends to make the corners wrinkle and their reinforcement value somewhat questionable. On a traditionally styled sail they really look out of place and are a pretty clear indication that the builder doesn't know much about traditional sails.

Round patches:

spritsail for an antique duckboat

duckboat-spritsail.jpg


single stitching is plenty

round copy.jpg

[Nicholas Carey]

There really is no need for anything sewn with V-92 on that sail. Tape basting combined with one line of V-69 is plenty for corner patches.

I was going to suggest that if you're unsure about the strength of your panel construction, seam up a small test panel. Wrap opposite edges around a 1x2 and run some bolts through it with fender washers on both sides.

Then take it to a testing lab and have them destroy it... err... test to destruction.

That's expensive, so hook one edge up to something immovable, and hook the other up to a come-along. Tension it up. Then count the clicks until failure. Record your measurement in your lab notebook.

Repeat with alternative panel constructions.

[Todd Bradshaw]

Wrap opposite edges around a 1x2 and run some bolts through it with fender washers on both sides.

Then take it to a testing lab and have them destroy it... err... test to destruction.

Not a great idea. As you can see on the sails posted right above, the idea is to gradually build up the strength of any area where you are going to put a fastener through the Dacron. If you want to do such a test, the only accurate way would be to essentially build up corner patches at the spots where your bolts will go through. Otherwise, the bolt holes will be the weak spots in the whole thing, not the seam. In any case, the test is pretty meaningless and not very accurate. A tape-basted seam with two lines of V-69 thread zig-zaged will distort the cloth badly and permanently as well as tear and elongate the needle holes before the stitches start breaking. There is also a factor called "dwell time" having to do with the adhesive on the double-sided mylar carrier basting tape. You can probably un-baste a seam for maybe a few days to a week after sticking it together with the tape, but after it has had some time, that becomes one of those situations where trying to pull one apart distorts and destroys the fabric. So, there is seldom any reason to worry about a tape-basted seam failing after it has had a week or two to dwell.

I tend to use three different types of seam tape. For most Dacron, my favorite is called "Venture Tape". It sticks very well and does not discolor the sailcloth as it ages (which some types do). On sewn seams on mylar laminated sailcloth a tape which has a very light woven Dacron carrier is used. The Dacron keeps the needle holes from elongating and tearing in the mylar sailcloth. I built a big radial-cut Genoa for our trimaran once and used 3M Supertape. It is so strong that for most panel seams on mylar sailcloth you don't need to sew it. The only seams in the entire sail that were sewn were those joining big sections and the luff tape seams. It has no carrier, just a line of goo when you pull the paper off and it tends to make really smooth sails, especially nylon spinnakers. It is pretty pricey though.

Mylar with Technora X-ply. Seams are all made with the tape with the Dacron carrier.

Speedball 1.JPG

Mylar Technora (black) scrim laminate and Mylar polyester (white) scrim laminate. Radial corners used where they are appropriate.

Trimaran copy.jpg

Kevlar/Mylar laminate mixed with 3 oz. white Dacron

Mini-12 4 copy.jpg

[wbuford22]

This is good information. I’ve had a copy of the Sailmaker’s Apprentice on and off my bookshelf for two decades-ish, and have recently been doing more reading to try to see if it were truly feasible to make a sail myself. Mostly for entertainment value, just doing the test panels has been a fun experience, although I’m certain greater frustration awaits. Getting the kit from Sailrite seems like the best way for me to get all the Dacron panels cut, so I suppose it’s more sail assembly that I’m looking at. First attempt at a sewn ring below. Seemed to go ok, still thinking about ways to get liners, having read of the difficulties in sourcing them elsewhere on the forum. Sailrite has the larger size for the corners, these would be for the sail slides salvaged from the previous mainsail. Again, grateful for feedback, the “give it a try” encouragement coupled with the shoal warnings is helpful.

CE877CD9-BEF2-4F1B-8B90-0B971B28D8B2.jpg7B79C4D7-2FE8-46E8-8DCF-FFE809C685C6.jpg

[Todd Bradshaw]

Ring liners have become a real problem over the years. I once complained to one of the big wholesale sailcloth and hardware distributors about the dwindling lack of available sizes in the liners and the reply was "The guys who made that stuff are dead." Not much you can say to counter that one. I did know one fellow who was a plumber, and he made some pretty decent looking liners from copper pipe using a flaring tool, but I don't know much more about it. The other problem with the liners is that some of the setters for the liners are around $100 and you really need several of them in the different sizes. By the time I retired from making sails some sizes of liners could be found and some sizes of the setters, but many of them weren't the same sizes, so you could get liners, but no setter, or setters, but no liners that fit them.

The right side of the sample just above, showing the back side of the piece, needs more top thread tension to pull the thread intersections closer to the needle holes, and more bobbin tension to take the curves out of the zig-zags and pull them up tighter to the surface. Otherwise, the stitches are prone to snagging on stuff.

[wbuford22]

Yes, this is the original test panel from the first post repurposed for ring sewing practice.

[The Q]

Todd, you have just given me the solution, I have copper pipe, I have flaring tools.
But I'm not showing you my appalling hand sewing.

[Todd Bradshaw]

Ring sewing does take some practice. Part of the problem is that you can't really see how well a stitch is aligned with the others until it is already done - at which point it is too late to fix it if it is out of alignment. One trick is to punch out the big hole in the ring's center, slightly smaller than the ring's inner diameter. Then place the ring in position over it and then trace around the ring with a pencil. Take the ring off, lay the fabric on a block of wood and then take a 4D finish nail which has had its tip ground to a fine point and pre-punch the stitching holes all around the tracing. Since you aren't trying to hand hold the cloth and there is nothing blocking your view, it is much easier to align the needle holes and you can do it either all of them aligned on the pencil line, or the method where every other hole is spaced back from the ring a little bit (as far as I have been able to tell, there is no strength difference between them, and if you ever had to remove a well-sewn ring of either type, it is a real bear).

The pre-punched holes don't even have to be full-sized to fit the needle, they're just markers. When you then sew the ring on, your sail needle will enlarge them as needed. Wax the twine well and then really work hard to twist or untwist each stitch as needed to make them all lay neatly as you pull them tight.

ring sew.jpg

[wbuford22]

Thank you for posting, the pictures are helpful!

Is an eyelet setter fundamentally different from a grommet setter? Various venders seem to use a variety of terms for grommet dye/setter/eyelet tools. The eyelet setters on Sailrite are visibly distinct from their grommet setters, but they are also larger than the largest grommet setter that they sell. Stimson's website also appears to have eyelets in every conceivable size and length, albeit with a large minimum quantity. Are these suitable for sewn ring linings? What would be the correct barrel length (buying them 1000 at a time makes one leary of trial and error).

https://webstore.stimpson.com/gs-eyelets

[Todd Bradshaw]

Yes, eyelet and grommet setters are different and not interchangeable. In addition, there are two types of grommet setters. Those found in hardware stores are called washer grommets and they are of no value for sailmaking or cover making because they don't grip the fabric well enough to be strong. They are also frequently brass plated steel, which rusts. The ones we use are called spur grommets. They have a rolled rim on the barrel part and teeth on the washer part. The teeth pass through the cloth and lock under the rim of the barrel part. They are quite strong and available in brass or nickel-plated brass.

The eyelets you mentioned above are not the type we need. They are shoelace-style, not sewn ring eyelets. Currently, I suspect that Sailrite may be the only place carrying sail eyelets. They were having some made for them a while back after the original supplies ran out. Here are a bunch of setters with spur grommets on the left and ring liner eyelet setters on the right. The grommet setters are Stimpson - pricey, but the best available. The ring setters are from Lorde and Hodge. I bought them nearly 40 years ago and don't know whether or not anybody still makes them. As I mentioned above, these days finding rings, eyelets and a setter that fits them all in the same size can be quite difficult. The little #000 spur grommet is from Hopkiss in England. I use them for anchor holes for cringle thimble corners on small sails. Linking several grommets or sewn rings for bigger sails together spreads strain out over a large area.

setters.jpg

eyelets-and-spur.jpg

cringles.jpg