Trim for a blackcat

[Dutch]

I am almost done with my diy Blackcat tarp. I am at the point of deciding to use trim or not to trim. Do you use double folded bias tape or is there something better? Also does the trim serve any purpose other than cosmetics such as does it add strength? I took my time and my hems look perfessional so if the trim is just to cover up crooked seems, I'd prefer to show off my handy sewing abilty.

[lvleph]

I didn't trim and it works very well. Look at my gallery photos. I don't think it is worth the extra weight. I personally don't think it adds much strength.

[Rapt]

I intend to trim mine since I'm going to be using very light fabric. You can make your own "tape" for trimming if you want. I'll be using 3.9oz coated ripstop to make my just barely biased tape... cut on a 10-15 degree angle instead of a 45 degree one. Allows some conformance to curves, but is stronger than 45 degree bias.... With the cat cut it distributes the tension evenly along the edge.

If I was using heavier fabric I'd be less likely to do so, especially with a good rolled hem.

[warbonnetguy]

two reasons to use trim. it can be used to cover up a raw edge. if you use bias tape, like rapt mentioned, it will be stretchy and not provide anything structural.

if non biased trim is used, the traditional corner pull tabs (weak link in the tarp) can be left off the tarp entirely, and the trim can take the load. what this does, is distribute any force applied to the tarp (wind for instance) to the trim, which then can distribute it evenly among the several thousand stitches around the entire perimeter of the tarp (like a trampoline), rather than applying the same force to a few stitches at each corner. you have to incorperate cat cut sides to achieve this though, but such a tarp should be able to handle much higher forces, and as a plus, the tarp will be stretched much tighter than is possible with regular corner pull tabs.

i think this is a new idea though. after i came up with the idea, i decided to search for other tarps with non traditional pull tabs. i found that the granite gear white lightning uses the same concept. the tarp i had at trail days and the granite gear white lightning are the only ones like this that i know of. the white lightning actually uses trim folded over the edge, i use 1/2" nylon grossgrain ribbon threaded through a rolled hem.

[nartoff]

Warbonnetguy,

Do you have any pictures of how you connected the pullouts? I'm pretty new to DIY gear and have not been able to find any closeups of the Granite Gear White Lightnin tarp.

If you don't have pictures, could you please describe what you did?

[warbonnetguy]

the only pic i could find is here: http://www.hammockforums.net/forum/s...+hammock+specs

i don't have one right now to take a close up of, but i'll try to draw a diagram.

basically, each side of the tarp has one piece of grossgrain ribbon running through (and stitched into) the hem from one end to the other. at the corners, the hem is open and the grossgrain is exposed. this is your pull tab. i have a plastic o-ring there to minimize wear on the grossgrain ribbon.

the 2 end corners are different. i just take a foot or so of 1/2" flat weave nylon webbing and sew it (doubled over) to the ridge seam. the two long pieces of grossgrain ribbon terminate inside the stitching of these end pull tabs.

Warbonnetguy,

Do you have any pictures of how you connected the pullouts? I'm pretty new to DIY gear and have not been able to find any closeups of the Granite Gear White Lightnin tarp.

If you don't have pictures, could you please describe what you did?

[warbonnetguy]

here's a drawing.

[Peter_pan]

two reasons to use trim. it can be used to cover up a raw edge. if you use bias tape, like rapt mentioned, it will be stretchy and not provide anything structural.

if non biased trim is used, the traditional corner pull tabs (weak link in the tarp) can be left off the tarp entirely, and the trim can take the load. what this does, is distribute any force applied to the tarp (wind for instance) to the trim, which then can distribute it evenly among the several thousand stitches around the entire perimeter of the tarp (like a trampoline), rather than applying the same force to a few stitches at each corner. you have to incorperate cat cut sides to achieve this though, but such a tarp should be able to handle much higher forces, and as a plus, the tarp will be stretched much tighter than is possible with regular corner pull tabs.

i think this is a new idea though. after i came up with the idea, i decided to search for other tarps with non traditional pull tabs. i found that the granite gear white lightning uses the same concept. the tarp i had at trail days and the granite gear white lightning are the only ones like this that i know of. the white lightning actually uses trim folded over the edge, i use 1/2" nylon grossgrain ribbon threaded through a rolled hem.

WBG,

Take another look at the stock Hennessy flys.... Believe it is also a continuous loop of tape with just excess formed into a loop at the corner.

Pan

[warbonnetguy]

yeah, but there is no cat cut, so it doesn't work like it could. same thing with the eno flies. thats why you never see one of those flies set up taut. they flap around like a flag in the wind.

in a perimeter loaded design, the cat curve is even more important in the tensioning of the tarp than with say a mac cat style tarp. with a mac cat style, the cat cut just removes excess loose fabric at the edges, the corner pull tabs stretch out the interior. the cat cut doesn't actually effect the tautness of the interior of the tarp like it can on a perimeter loaded design. in a perimeter loaded design, the webbing/trim in the curves wants to flatten out when pulled upon by the guylines. so it tries to, pulling the tarp with it and stretching out the sil in all directions like a trampoline in the process. the result is the tightest possible pitch and a tarp that distributes any force evenly among as many stitches as possible. such a tarp should hold up to alot heavier wind forces.

WBG,

Take another look at the stock Hennessy flys.... Believe it is also a continuous loop of tape with just excess formed into a loop at the corner.

Pan

[lvleph]

The hem along the edges already distributes the forces along the edge. I still firmly believe it is for aesthetics alone.