Questions about making a silnylon tarp?

[Big Dawg]

I have 8 yds of grey silnylon & am soon going to make a "MacCat style" hex tarp. I'm new to sewing, & will be using my neighbor's sewing machine. Some of the other projects I was considering include an underquilt for my new hammock, but based on time & sewing skills, I'm having Patrick (KAQ) make my underquilt. Making a tarp seems simple enough, though,,,, so, here's my questions:

#1. What's the best needle to use for 1.1oz silnylon?

#2. What's the best thread to use to construct this tarp? I've seen 100% nylon thread in my local fabric store, but notice Brian (OES) uses urethane coated 100% polyester thread.

#3. Is webbing another name for grosgrain ribbon? I plan on lining the edges w/ a fabric, like Brian/OES does,,, & I think I remember a past post explaining he used grosgrain ribbon.

#4. Before lining the edges w/ webbing, do you still fold over the edges of the silnylon (like you normally would if not using webbing)?

#5. The tie-out corners. It seems I remember a post where a small piece of regular nylon is sewn on the top & bottom of each corner tieout to reinforce the tie-outs. Brian's website states using 1000D Kevlar ripstop for those corners. Should this reinforcement fabric be waterproof, non-waterproof, DWR or what,, or does it matter?

#6. D-rings for corner tieouts. Brian uses ABS plastic D-rings. What does ABS mean?

I think this does it.

Thanks for all reply's!!!

[Footslogger]

Can't help you much with the silnylon questions ...since I'm still in the learning states myself.

But ABS stands for "Acrylonitrile Butadiene Styrene". It's a type of plastic that allows things to me made light and rigid.

'Slogger

[general]

size 90 or smaller, basicly so the needle hole isn't much bigger than the thread dia.
i use bonded nylon thread (B46) for tarps
i would still fold the edges for strength even when banding with ribbon
i use 1 sil/nylon triangle re-enforcement piece, on the inside only, at each guyout point
after finishing the tarp, you should coat every millimeter of thread with silnet or regular silicone. that way if a thread does pop, later, under stress, it won't unravel.

[bugbomb]

Dawg - grosgrain ribbon is not the same thing as webbing. The ribbon is much lighter, and will be easier to fold and sew around the perimeter of the tarp if you feel that is necessary. You can get it pretty darned cheap at Walmart in a 7/8 inch width.

If it were me, I would definitely still hem the edges before lining them. Although, on my own tarp, I did not line the perimeter with ribbon - only at the guyout points. I basically folded the edge over twice and hemmed - I feel that this triple-layer of fabric, with no exposed edges, is plenty strong. One advantage to lining the edges might be that you minimize stretching/distortion under tension.

I'm not sure about the reinforcement material. I used uncoated nylon - I figure it may get wet and soak some water, but it will dry. If you use something coated (silnylon or urethane coated), be very careful that you seal the seams around it, otherwise it might hold water like a bag.

[hammock engineer]

I'm not sure about the reinforcement material. I used uncoated nylon - I figure it may get wet and soak some water, but it will dry. If you use something coated (silnylon or urethane coated), be very careful that you seal the seams around it, otherwise it might hold water like a bag.

I never thought of that issue. I am working on one now. I am just making a simple 9x9 square with tie outs at the corners. I'll post some pics when I get it done.

If anyone needs somewhere to order sil-nylon. I ordered seconds from Noah Lamport for $2.75 a yard. Recieved it in a week and it looks fine. Just do an all in one order. They charged a $5 cutting fee and around $5 for shipping off of the bolt.

[bugbomb]

HE - someone warned me about that before I made mine. It could by overly cautious, but I didn't see much advantage to using coated material anyways.

[Just Jeff]

Brian folds his edges under before he adds the grosgrain ribbon. I think the ribbon does two things:
1) Makes the edges stronger, which could be an advantage in high winds - think about how much the tarp flaps around when you're first setting it up in windy conditions.
2) Spreads the load. If you just hem the edges, then pull on the guyout point, it'll stretch a lot at the guyout point and not quite as much around the rest of the tarp. Adding the grosgrain ribbon adds some stiffness around the perimeter, starting at the guyout point. This means that force applied to the guyout point is transferred to more of the perimeter...resulting in less flapping when stressed.

Is it necessary? Probably not - plenty of tarps keep folks dry without it. But there's a video on my website of the MacCat in probably 30kt winds and it's barely moving.

Will it have the same effect on a square tarp? Probably not unless you curve the sides...but there's only one way to find out!

His kevlar is not waterproof, but it doesn't matter. The tarp is already wet if it's raining anyway, and it's such a small amount that it dries quickly enough when the tarp dries.

Where are you putting the seam to get a 9x9 square?

[hammock engineer]

I am going to sew 2 4.5'x9' pieces of sil-nylon together, adding 2" on each side for seam allowances. That should put the seam running down the middle. It won't be corner to corner, but that should not matter. Or will it? This is going to be my first sewing project, so I wanted to keep it easy.

How much weight would it add to put that around the outside? I'm planning on making 2. If it only adds a couple ozs, I will put it on the 2nd one.

[general]

How much weight would it add to put that around the outside? I'm planning on making 2. If it only adds a couple ozs, I will put it on the 2nd one.[/quote]

ounces add up. sil/nylon doesn't need the re-enforced edges, only a folded hem around the edge. the re-enforcement triangles at each guyout are enough. make these 6 or 7 inches on the hypotenuse,and do without the banding around the edge to save weight. the banding's got to add 2-3 ounces. the larger the triangle re-enforcement piece is the more tension it distributes.

[hammock engineer]

One more question for everyone.

What should I use as the tie out lines. In Ed Speer's book he calls for 1/16 inch Spectra pulse line. Should I use that as the side tie outs and the tie outs from the corners to the trees? I was also looking into using shock cord for all the tie outs. That would provide a little give to them, which should help in stronger winds.

[Just Jeff]

IIRC, Brian said the grosgrain on his tarps is about 1.5 oz.

I'm not sure how that seam will react - looks like a lot of force pulling the seam apart. Maybe run an extra line down the seam and use a thick seam-seal mix just to be safe.

I'm not sure I'd use shockcord by itself without some sort of "safety catch" made from Spectra (or whatever other non-stretch line you use). Most tarp tensioners only take up slack in a line rather than providing any "structural" support. Make sense? Here's an example:
http://www.tothewoods.net/HomemadeGe...nsioners2.html
See how the line runs through the middle of the tensioner? So if a wind gust stretches the tensioner to full extension, the line itself is providing the structural support and it doesn't matter much if the tensioner fails.

[stupe]

Favorite thread for me is Gutermann's polyester thread. I used a contrasting color on my purple silnylon tarp and it looks kind of cool. I wouldn't use any urethane coated thread since you're going to seal the seams, and maybe the urethane coating would prevent the silicone sealant from impregnating the thread. Maybe not, but keeping it all sil seems better to me.
I'd keep with that philosophy on the tie out reinforcements, too. Two layers of silnylon tucked under a hem is pretty strong. Even if you reinforce with kryptonite, it's only going to be as strong as the stitches going through the sylnylon layer anyway. Like that saying "a chain is as strong as it's weakest link', you know.
I did what bugbomb said above, folded the edges over twice and stitched through the three layers. I guess the ribbon could only make it stronger without adding much weight, and I wish I'd done that, although so far it's holding up good.
general above said that nice big corner reinforcements distribute the stress better, and he was right.

[hungryhowie]

The best thread I've ever used is provided by Thru-hiker.com. It's stronger and less messy to work with that Guterman, and cheaper too. Use the smallest needle you can and still fit the thread through, typically a 90 or smaller. A grossgrain ribbon perimeter is overkill...way overkill. I've designed, made, and tested many tarps and have yet to understand why it's sometimes used in this way. Because grossgrain also absorbs moisture, it weighs much more than 1.5-2.0oz when wet, and it takes much longer to dry than silnylon. I've experiemented with a silicone impregnated binding as well, but this did nothing for performance either. No, the best way to seal a silnylon edge is to burn it to prevent fraying, turn the edge under and hem. I lightly reinforce corners with a second layer of silnylon and use grossgrain for the actual pullouts.

-Howie

[fiddlehead]

For tieing out the guys, i found that the super strong nylon string that union bricklayers use is the lightest. I have it on my sil-shelter going on 6 years now and have never broken one. I've been in some pretty big storms too. good luck. i think you'll find that the reinforced sil-nylon is pretty damn strong although very slippery and not easy to work with.

[Big Dawg]

Thanks all, so far!!! I can't wait to get started!!!

[Big Dawg]

I lightly reinforce corners with a second layer of silnylon and use grossgrain for the actual pullouts.

-Howie

How strong & long-lasting is grosgrain ribbon as "pullouts". Is using nylon webbing & heavy duty plastic D-rings overkill?


.

[Big Dawg]

The best thread I've ever used is provided by Thru-hiker.com.
-Howie

They have Tex 40 (used for tarps/packs/sacks) & Tex 24 (for apparel/sleeping bags). Obviously I'll get the Tex 40 to make my tarp, but do you think it would be ok to use Tex 40 to also make me some rain pants using 1.1oz nylon ripstop w/ DWR?

[general]

How strong & long-lasting is grosgrain ribbon as "pullouts". Is using nylon webbing & heavy duty plastic D-rings overkill?


.

86 the plastic man. use the nylon to make a loop (better both ends of the loop are sewn to the inside of the tarp rather than one end on the top and one end on the bottom). plastic weighs more than nylon and you've got to use the nylon ribbon to attach the d ring anyway.

[general]

They have Tex 40 (used for tarps/packs/sacks) & Tex 24 (for apparel/sleeping bags). Obviously I'll get the Tex 40 to make my tarp, but do you think it would be ok to use Tex 40 to also make me some rain pants using 1.1oz nylon ripstop w/ DWR?

you can use the tex 40 to do just about anything except maybe underwear and anything thats gonna hold down. you will have to seal the seams on the rain pants too.

[Big Dawg]

86 the plastic man. use the nylon to make a loop (better both ends of the loop are sewn to the inside of the tarp rather than one end on the top and one end on the bottom). plastic weighs more than nylon and you've got to use the nylon ribbon to attach the d ring anyway.

Sorry, I'm new to making my own gear,,,,, not sure if I follow ya.

"86 the plastic man"??? what does this mean?

I thought my choices were: #1. Use nylon webbing, make a loop w/ D-ring in the loop,,,,, or,,,,,, #2. Use grosgrain ribbon, make a loop,,,,,, attach either one to tie-out corners.

Either option I choose, I had planned to sew one end on top & one end on bottom of tarp,,, but General,, you say both underneath/bottom,, why???


.