Or just a good excuse for yet another tarp thread? Well, I recently finished a tarp and found a way to eliminate wavy stiches altogether, although I 'm sure not everyone will find it practical. I realised that by just advancing the machine manually, the stitches came out perfect. OK, it's a bit time consuming, but it's only when you sew silnylon, and I appreciate that many will be able to sew perfectly well at speed. However, if your new to myog and your having real problems balancing the stitch, it's there as a last resort. At least you get something that really looks good when it's finished. I think that when you're new to myog those first few projects are really important. A nice looking tarp is a big boost to morale and thus an encouragement to the beginner to continue in this highly rewarding hobby. The thread tension is not so critical when you advance the machine manually. Here are the results, purely for demonstration purposes of course:



Here's the ridgeline



and a tie out



I like to sandwich the sil nylon in the middle of the tieout: it's a technique used in parachute manufacturing to eliminate any possibility of a peel tear. It's a bit tricky and a pin helps, but the result is a bomber tieout.



I was in my local sewing shop last week, and saw a modern electronic machine with a DC motor. It was able to sew at very low speed (about one stitch per second. Now I'm not saying go out and get a modern electronic machine. However, I wonder if any bpl members have a machine with a dc motor, some of the ladies perhaps? Has anyone tried sewing silnylon using a very slow speed setting? Could speed be a major factor in how silnylon sews? Of course, even if they sew silnylon well, they would probably be unsuitable for other kinds of heavy duty sewing. On the other hand, I know many members have more than one machine, and use different machines for different kinds of sewing. Also, many people have someone in the family with an electronic machine. Personally, having gained experience the hard way, I would want to borrow any prospective purchase for a week or two and see how it sews a whole tarp (not always possible of course). I often find that sewing scraps does not always provide a clear picture of how the whole project will sew, because different sides of the fabric have different amounts of coating, and hence, different degrees of slipperyness. I'm afraid I don't know that much about sewing machines. I only raise the issue of DC motors for further investigation and comment by those with many years more experience than myself.
Matt

Edited by Skyaddict on 07/13/2012 05:18:38 MDT.

Many machines have a DC motor. I can run mine from the plug in the wall or from a car battery.

I would try just about anything before I resorted to manually advancing my machine for 40' of stitching.

Practice, practice.

Nice job on the tarp.

It sounds like a DC motor is not the only factor then. The machine I saw had electronics and the extremely slow speed was selected via a small screen. Of course, sewing very slowly would probably be no more acceptable to some people than advancing the machine manually. Part of the problem for me is that my record 830 is stuck on fast and the max/min switch does not work. The switch is going to be hard to replace, I may get it set on slow and forget about the max setting. I think speed certainly exacerbates the stitch problems.
Matt

Edited by Skyaddict on 07/13/2012 08:48:44 MDT.

Matt -- very nice looking tarp. Amazing you hand-turned the machine. Have you though of using foot treadle driven sewing machine?

Nice looking sky for the UK.

If you had the switch fixed I bet you would have no further issues. Unless your foot pedal contacts are bad. You should be able to ease the machine into slow speed operation. My Janome has a two speed switch as well. I can ease into it on high. Just checked.

Hi Tim,
thanks for the kind words regarding the tarp. If done in one go, I would say it takes about a day to do one tarp. I wouldn't go for a foot treadle machine myself. I really see hand turning as a last resort: it's impotant to practice of course, but I also think it's important for the absolute beginner to have at least some way of turning out something they can feel proud of (I know what a downer wavy stitching can put you on). They can perfect the dark art of silnylon sewing in the years to come. I am considering looking at machines that sew more slowly than the one I have though; not electronic, just slower. After all, for the price of an electronic machine you could probably get a semi industrial. I want to actually sew on them before I buy, whatever I choose to do. The sky? Ah yes, a rare glimpse. And a good ad for the camera on the galaxy S2. Cue another months torrential rain, did I mention we're in the middle of the worst summer on record. I hope you are not on your way to UK! Great tarp testing weather though.
Matt

Edited by Skyaddict on 07/14/2012 13:10:00 MDT.

I have just joined berninathirtysomethings and am still ploughing through the wealth of info on that site. It seems the foot control was not one of Bernina's strong points. Mine does seem to grab sometimes. I can ease back to a slowish stich, but I can never start slow. They can be adjusted, it's just finding out how. As for the switch, I will just try to get the machine set permanently on slow.
Matt

Matt,

What is that bit of shock cord that appears to be under or behind the webbing of your tie out?

Party On,

Newton

The shock cord is just a loop through the tie out. It is flipped that way because it helped me to thread the guyline through the tie out. Normally it would just project outwards. It's nothing special, it just helps when pitching down to the ground in bad weather, like a traditional tent flysheet. FWIW I discovered that mini linelocs don't work with 250lb 1mm dyneema fishing line. They work at first, but gradually squash the line flat until it begins to slide. Shame, the line was 6.99 off ebay, and it's made by climax in Germany, so high quality. I'll just have to use slings.
Matt

Edited by Skyaddict on 07/15/2012 04:14:01 MDT.

Nice tarp! Can you comment on the construction of the tie outs? I just made my first tarp with triangular corner reinforcements with a single line of stitching across the angle and very much regret it. All the tension is focused on one line of stitching, leading to stich hole widening and probably failure after much use.
Is your reinforcement glued or bonded in some way? And if so did you notice problems sewing through the adhesive?
Thanks, Steve

Hi Steve,
the tie outs are circular, obviously. Intuition suggests that this distributes stress more evenly, although there are no official tests so far. I tend to overbuild slightly, in order to make up for any deficiencies in construction, hence, quite large patches. They mabye don't need to be quite so big. I like to bond them with builders silicone as stitching seems to me an obvious weakness. If you have never bonded silicone patches on, believe me, they are immensely strong. I found some intersting stuff called SUMOGRIP. It is a rather thick silicone caulk that purports to be a revolutionary grab adhesive. Well, hype aside, I think it's just mabye a higher modulus silicone. Someone realised builders were using silicone for other purposes, and brought out a slightly thicker version. It does a reasonable job of bonding silnylon though. There is a great article in the articles section about bonding silnylon, the silicone they use there may be better, personally I like to do things as cheaply as possible and use what's available in the local hardware store. Technically the silicone does not bond the fabric, rather, it gums it together. If you get a knife under it you can still peel the patch off; that is why you'll never see them on a commercial tarp. However, for the home builder they are quite serviceable, if they begin to peel just glue them back down. I orient the ripstop in the patch so it lies at 45° to the ripstop in the tarp. That creates a high bias (stronger) patch. Always leave the patch for several days before sewing: silicone takes quite a while to cure fully. Once cured it sews ok, but then, I hand cranked. You can see little bits of silicone on the needle, so at speed it might cause problems. You can always hand crank across the patch, check the needle carefully, and then sew on normally. I also pin everything, even the hem. If you want it neat it's the only way. Good luck.
Matt

Edited by Skyaddict on 07/15/2012 04:50:21 MDT.

I've just been doing tie-outs by sewing a bar tack through the hem, which I see you do in addition to the reinforcement siliconed on

I don't camp in hurricanes, but I do windy conditions sometimes and haven't noticed any failures.

Also, I haven't tested it for years.

I'm into doing things as simple as possible. The reinforced tie-outs don't really weigh any significant amount extra. It does take some extra time to cut and silicone the reinforcements and wait for it to dry.

Thank you both. Should have done this on my project, but I was too paranoid about sewing through the adhesive because I am using a borrowed machine which carries with it much sentimental value. If you can see the needle picking up silicone then it seems like there is a real possibility of it gunking up around the bobbin. Would this work: Catch the reinforcement piece in both hems, sew on tieout, then glue down as much of the 'flap' as possible?
steve

I think that would work

sew, then glue down flap

If you look care fully you will see that I use a loose zig zag rather than a bar tack, which I think is unnecessary and over perferates. With a loose zig zag you can go back and forth to create a bartack if you want one, and that locks the stitch better as well. I coppied it from golite who use a similar technique. I also start my Xbox at the back of the patch so there is never any perpendicular pulling at the start of the stitching. I don't capture the patch in the hem, but now you mention it, more layers can't hurt. As for gunking up the bobbin, if you let the patch dry well that shouldn't happen. I've never had it happen to me. Just check the bobbin afterwards if you're worried, it's not like it can't be cleaned.
Matt

Yeah - on the loose zigzag/bar tack

The needle holes shouldn't be closer than about 2 mm. Set the stitch length to 1 mm, so the holes will be 2 mm apart on each side. And then reverse on both sides with a 2 mm stitch length straight stitch to lock the thread.

And if you have a flat felled seam that connects two pieces of fabric, then you can do the same with it. Sew the webbing to it with a zigzag/bar tack. Then you don't need any reinforcement.

My understanding on your technique is that you:

1) cut out a circle
2) cut it into fourths (one for each corner)
3) bond/glue the reinforcement at the corner where the hem will fold (leave 1/4" between the edge of the fabric and the flat edges of the reinforcement)
4) let the bond/glue cure over a few days
5) fold the edge of the fabric over the reinforcement and sew your hem.



Additionally, you mention that you pin your hems before you sew them. Have you tried putting a drop of the glue/bonding every couple feet at the same time you do your other glue/bonding? Do you still iron the seam before sewing like most do?

I don't see why you would pin the hems

If you wanted, you could put a line on the fabric where you wanted the edge of the finished tarp to be. Then just fold it over twice as you're sewing the hem.

I can see pinning where you join two pieces of fabric making a flat felled seam, so one piece doesn't slip relative to the other.

Unnecesary pinning puts holes in the fabric and takes extra time.

>1) cut out a circle< Correct.

>2) cut it into fourths (one for each corner)< Not quite. I fold them in half so that the ripstop is aligned diagonally to produce the high bias orientation. Then I cut them in half and lay one half on a corner. The tarp is cut back by 10cm from the ridge so the corners are more than 95 degrees, therefore I need two circles to provide 4 halves.

>3) bond/glue the reinforcement at the corner where the hem will fold (leave 1/4" between the edge of the fabric and the flat edges of the reinforcement)< Correct. I leave 20mm for the hem, but 10mm on one side of the felled seam, and non on the other. That way the patch is grabbed by the seam and much stronger. I find a battery helps roll out any air bubbles, and a rag with meths helps clean up. You could experiment with the patches at the hem, but it might get tricky sewing the corner flat if you don't leave a gap as the patches are quite stiff when fully cured.

>4) let the bond/glue cure over a few days< Correct, 72 hours min.

>5) fold the edge of the fabric over the reinforcement and sew your hem.< Correct.

>Have you tried putting a drop of the glue/bonding every couple feet at the same time you do your other glue/bonding?< I find pins work fine if you use enough. There seems to me nothing to be gained in terms of strength from bonding the hem.

>Do you still iron the seam before sewing like most do?< I haven't got an iron, but if I had one I would certainly use it on the seams.

>I don't see why you would pin the hems< I found on one tarp I made the material was stretching as I sewed it and thus the hem didn't line up properly. Maybe I'm being over cautious, but I didn't want to take any chances. I may have spoken hastily when I said above it was the ONLY way to get them neat.

>Unnecesary pinning puts holes in the fabric and takes extra time.< I don't think that's a problem in the hem, is it?

Threadwise, I use Rasant 120 for the ridge and hem, and Rasant 75 for the tie outs. I use a Schmetz microtex 60 with the Rasant 120 and a 70 with the Rasant 75.
Matt

Edited by Skyaddict on 07/17/2012 01:00:53 MDT.

Yeah, probably holes in the hem aren't an issue since it's on the edge.

I was just looking at some hems and they seem to be lined up without doing anything.

I just hate doing a bunch of unnecesary fiddling.

As you're sewing the hem, fold over the next section twice and flatten it out good with your finger. Doesn't slip. But, whatever works is good. Different machines and fabric are different...