Going in head first: Tarp questions

[griffins]

Hey guys just a few questions about making my own tarp.

Disclaimer: I have zero sewing experience and have never actually seen a hammock tarp. However, I am as stubborn as a mule and believe I can do anything (and slightly OCD... ok maybe largely)... so here we go.



Tie outs: To the best of my understanding from reading through the forums tie-out construction should go: tarp sil -> rein patch -> rolled hem -> GG tie-out. The first part of my crude drawing shows how I believe the sewing should happen i.e. GG tie-out is on the "top" and "bottom" of tarp, acting as the quasi-buns to my material hamburger. Is this the general idea?

Additionally, how should I attach the reinforcement patch to the tarp? Adhesive? Stitching? When attaching the GG tie-out loop to the tarp does it get sewn to the reinforcement patch, the hem of the edges, both, or some of the above?

Dimensions: I am currently in a WBBB. I have read that the OES Standard is just shy of being long enough (along the ridgeline) for most people. However, I am not sure I would want the width of a deluxe. Someone (cant remember who) had a custom Deluxe-length/Standard-Width tarp made. This configuration would seem to suit me better and these configurations (at least length) seem to mirror Brandon's. Any suggestions or input on dimensions?


*Cat cuts are a little aggressive as my paint skills at not very high*

Additionally, what determines the length between A and B (in the picture above)? Obviously, a longer length provides more coverage. Long length for winter tarps, shorter for summer. Got it. Exact length? No idea. Length I think I need? I don't know, a medium length. How long is medium in relation to the ridge line? No clue... you get the idea. Any help?

Finally, how exactly do I provide seam allowance for the cat cuts and perform a rolled hem without bunching of material? Do I just add seam allowance the intuitive way? Seems like that would not really "roll" very cleanly. Do I cut little slits in the seam allowance to aid the material in lying flat? Or, am I simply envisioning the cat cut as more aggressive than it actually is and the material lies easily?

Well, I guess that was a lot of questions. Anyway, thanks for your time and input, I appreciate it.

[Ramblinrev]

Start with the Black Cat tarp directions in the forums. It is a tested and refined pattern that answers a lot of your questions. The directions are good and the process is fairly straight forward.

[Strapped-4-Cache]

Thanks, guys.

This information has given me answers to my questions I posted in the Weather Protection section. I feel a bit better about knowing how to add tie-outs and pole pockets since I've had a chance to read this information.

[gargoyle]

I will make a suggestion here.
If you have not sewn before, practice up first on some small projects, (stuff sacks, a jerry chair, ridgeline bag, etc.)
Silnylon is fussy to work with, slippery stuff. Practicing on some smaller projects will give you a better feel for the machine and the fabric. Starting out on a big tarp project can lead to a lot wasted $$ and time. Even people who have sewn alot have trouble with sil.


Good luck.

[JohnSawyer]

I too am a noob at this but:

My first (and last) tarp project was a 8x10 rectangular that I made from cheap walmart 1.1 DWR, from the instructions in Speer's book while I was learning to sew.

I had some issues with it, but it was a great learning experience. (yes my flat felled seam works, but it isn't terribly straight...)

My advice: buy 2 packs of pins, a few new needles, some really cheap nylon ripstop (if you can find it) and practice like Gargoyle said.

Personally, I sprayed down my tarp with some silicone waterproofing spray, and it seems to work well-enough in our so-cal rains. (It did well in 3 rainy days in the back yard) and it's a heck of a lot lighter than my tyvek tarp I used before...

if I had to do it again, I'd probably go bigger so I could stand under the tarp with one edge on the ground, but I count in increments of 1/4 pound, not grams...

Unless you're a gram counter, I'd also consider straight-cut beaks for any tarp, it's nice to close up the ends...

I might just take that tarp and cat-cut the sides someday, as it is a little bit floppy, but the material is quiet, so I don't have a big issue...

--John

[WarmSoda]

construction should go: tarp sil -> rein patch -> rolled hem -> GG tie-out. ... Is this the general idea?

yes, that's it exactly. you want to sandwich the material between the tieout. This is not the only way to do it, though. Some use the GG as a border and make a loop at the corners before continuing on the other cat cut section. The border method will probably be stronger, depending on how you attach and sew, but not as easy to manufacture.

Additionally, how should I attach the reinforcement patch to the tarp? Adhesive? Stitching? When attaching the GG tie-out loop to the tarp does it get sewn to the reinforcement patch, the hem of the edges, both, or some of the above?

Adhesive would mean that you didn't need to seam seal as much and might have a stronger reinforcement. Stitching is more commonly used and might avoid some extra weight of the adhesive. Stitching also allows the creation of pockets for the tieout lines, so they won't tangle. Sew the GG through as much material as possible to distribute the tension forces over a larger area. Usually using a box-stitch will cover as much area as the GG will allow. I've seen people use bar tacks instead of box-stitches, but bar tacks aren't as strong for this application, I don't think. I've read somewhere that just several parallel lines running the length of the GG is the strongest stitch for webbing slings (webbing to webbing) and it would make sense to do that here as well.

Finally, how exactly do I provide seam allowance for the cat cuts and perform a rolled hem without bunching of material? Do I just add seam allowance the intuitive way? Seems like that would not really "roll" very cleanly.

Add as much material to make the tarp as big (wide) as you think it should be, then yes, add another inch or two for seam allowance. Don't forget the the ridgeline seam will take up some and the rolled hem will take up some.

Do I cut little slits in the seam allowance to aid the material in lying flat? Or, am I simply envisioning the cat cut as more aggressive than it actually is and the material lies easily?

Don't cut little slits. Silnylon will stretch enough to cover the curves that cat cut will give you. Over several feet, a few inches of curve won't even be noticeable when up close under the sewing machine.