how to cut the ripstop for a tarp

[Ladybird]

It is too late for me now, I've already cut one side of the tarp....

but when using the ripstop with the little boxes, should you cut the ridgeline with the grain, or on the diagnal? Would cutting on the diagnal give a better stretch? I cut along the lines to assure a straight cut, hope I did it right

[MAD777]

I cut mine the same way you did. There is significantly less stretch along the ripstop lines than there is on the diagonal. You can take a piece of scrap and pull it in your hands and tell the difference. You can even tell when pulling it through the sewing machine.

[jdneri]

Thats how I do it. Not only does cutting along the lines give you a great cutting guide, it also squares up the fabric. Strength has never been an issue doing it this way. Now if you want to make it a cat-cut, that is a different story. The way I made mine was to first square up the fabric to the dimensions you want it to be. take some poster board and tape it onto the wall and make sure its level. decide where you want your curve to be it's deepest and make a mark right in the middle. Take two thumbtacks and stick them into the board where the corners of your tarp edge would go, then hang some string between the thumb tacks with enough sag to hit the mark you made for your curve depth. carefully tape the string to the board and mark the resulting curve with a sharpie ...... you know what, i can't explain it well. take a look at this...

http://www.teamgunnparker.com/blackc...#_Toc173479851

Hope that doesn't muddy the waters!

[rjcress]

I cut mine the same way you did. There is significantly less stretch along the ripstop lines than there is on the diagonal. You can take a piece of scrap and pull it in your hands and tell the difference. You can even tell when pulling it through the sewing machine.

I'll second what Mike said.
Can't wait to see the pictures of the finished product.

[Ladybird]

Well that is how Ive started, and am excited to get it finished. It is grey, and I bought black ripstop for the reinforced corners. I'm not going to edge with the grosgrain, just roll em up.

Should I use a thinner needle to sew it? Ive never done ripstop, and it seems so fragile!

[PuckerFactor]

I usually use a size 12 needle for ripstop, but sometimes use a 10 if I feel like it. Use whatever size you feel comfortable with.
I can empathize, I felt the exact same way when I first started sewing 1.1 ripstop!

PF

[Ramblinrev]

Should I use a thinner needle to sew it? Ive never done ripstop, and it seems so fragile!

As you will soon find out, ripstop may be fragile as compared to 1000 D ballistic nylon packcloth, but it is a very durable fabric. It will survive some very rough handling. Needle size is one of those mysteries that people overly fixate IMO. I like a big needle because I can't see to thread the tiny little eyes. However, if you use a larger needle you have to keep it very sharp as it is more likely to punch the fabric down into the throat plate. This is especially true if you are using a "universal" point rather than the older "sharp" styles. But as far as a "right or wrong" it is not important. As long as the stitches are good it really doesn't matter. IMO. Unless of course you are doing commercial work. Then you need to check with the industry standards. But for your own personal choice... whatever you are comfortable with.