DIY Tarp Idea... Save some fabric?

**hppyfngy** · 05-23-2011, 18:32

I've been wanting to make a tarp and I had an idea. Why not seam it on the diagonal and save on sil?

All the directions and patterns I've seen either seam down the ridge or across the middle. Here's my thought:

My pattern (yep, I drew it on paper!

) gives me a tarp that's approximately 12' long and 7' across, (6' long at the edge.)

If you seam it this way you can get the whole length out of about 15' of fabric.

All the patterns I've seen call for 8-9+ yds, I think I can do this with 5 yds. This shape is just a rough idea, I didn't do any math to optimize it, but the width is easily done with 60" fabric.

What do you think?

**Dutch** · 05-23-2011, 18:41

That is a good idea and uses the the most out of your materials. The only thing that comes t mind is you won't have the ridge line down the center. That's ok and there are many tarps like that.. JRB 11x10 comes to mind. You may want to do a continual ridge line.

**jerseydave** · 05-23-2011, 18:44

Might want to add a piece of grossgrain running the length of the ridgeline and end it as your tie outs.

This way the stress isn't put on your seam.

jd

**Catavarie** · 05-23-2011, 18:54

My only concern with doing it this way, and please don't let it discourage you because I want to see your results from it, is that if you use SilNylon and cutting at an angle like that the cut edges are going to have A LOT of stretch. This means that in high winds it may not be as stable as a traditional tarp seemed along the ridgeline.

**Detail Man** · 05-23-2011, 18:57

The only thing I see that might be a problem, and it might not be, is that the direction of pull along the ridgeline is on the bias. This might cause more stress along the seam. If you have some small pieces of sil, it would be prudent to make a scale model and test it.

Neat idea.

**hppyfngy** · 05-23-2011, 19:06

Thanks, I know it's a little squirrelly putting everything on the diagonal. I am also concerned about stretch as most of the force will be diagonal and on the bias.

Just thinking out loud... (and being a cheep mook

)

**gargoyle** · 05-23-2011, 19:26

Going diagonal can be troublesome.
Test it out on some good sized scraps. It may work.
Perhaps sandwiching some grosgrain in the seam to help stabilize the "stretch" factor.

**hppyfngy** · 05-23-2011, 19:45

Originally Posted by gargoyle

Going diagonal can be troublesome.
Test it out on some good sized scraps. It may work.
Perhaps sandwiching some grosgrain in the seam to help stabilize the "stretch" factor.

I actually thought about putting grosgrain along the seam and across the other diagonal, like and "X". I'm afraid I might start to get a bunch of flap if I do that though...

hmmm...

**Ramblinrev** · 05-23-2011, 20:44

Originally Posted by hppyfngy

I actually thought about putting grosgrain along the seam and across the other diagonal, like and "X". I'm afraid I might start to get a bunch of flap if I do that though...

hmmm...

Too much stabilizing can be problematic. You'll want to pitch it first and see where the real stretch points are. The diagonal seam will be stabilized somewhat by the flat felled seam if that is what you use. (I would suggest going with a true flat felled seam in this application because of the stability it gives. YMMV). Crossing the tarp with another length of grosgrain could present some weird stretch issues that preven you from getting a good taut pitch. I'm no engineer so this is just my gut talking, but I would not do any additional stabilizing until I'd had in hung in a variety of situations.

**gmcttr** · 05-23-2011, 20:49

FWIW...the Sportsmans Guide, Guide Gear 12x12 tarp is stitched on the diagonal. It has two seams due to it's length. It does not have reinforcing on the ridge or edges.

I have one, but have not used it enough to advise you.

Please proceed and do the leg work for all of us.

Thanks

Edit...Whoops...the GG tarp has three diagonal seams. When pitched in a diamond configuration, one is on the ridgeline.