5.5oz Cuben tarp with carbon tieouts
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sam jepsen
(SamJepsen) - M

Locale: Southern California
Awesome Job! on 05/11/2014 10:56:32 MDT Print View

That is a truly impressive piece of work!

Is there an equation for determining the degree(?)/arch(?) of a catenary curve? Or do you just trim what would otherwise be a straight edge into what looks like a reasonable curve?

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Awesome Job! on 05/11/2014 11:42:51 MDT Print View

When I've free-handed curve it didn't come out right. There were wrinkles and such.

Both Roger and I have articles in make your own gear about tarps and catenary curves. I stole xls file from Roger. Make straight line. Mark every 2 inches. Measure distance from center for each point.

Or you can do this one time and make a pattern and then use it.

Or you can suspend a heavy line between two points and let it hang, and then trace this curve.

The exact curve isn't that important, but it has to be smooth or your tarp won't pitch tautly

sam jepsen
(SamJepsen) - M

Locale: Southern California
Re: Re: Awesome Job! on 05/11/2014 11:55:30 MDT Print View

Thanks Jerry! I just looked up those posts.

Nicholas Smolinske
(Smo) - F
Re: 9460 Tape on 05/11/2014 15:35:30 MDT Print View

Stephen: In an astounding coincidence I was researching transfer tapes on Friday (for sealing Xpac seams) and found out that Amazon has 9460 rolls individually:

http://smile.amazon.com/gp/product/B004V40D5I/ref=s9_simh_gw_p328_d2_i5?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0P3CDWDJWA03T459K3VD&pf_rd_t=101&pf_rd_p=1688200382&pf_rd_i=507846

That's the 0.5 inch, but they also have 1 inch.

Steve B
(geokite) - F

Locale: Southern California
9460 on 05/13/2014 16:29:47 MDT Print View

Sorry for the late reply, haven't checked this part of the forum in a while.

I got my 9460 from a local supplier, RS Hughes, her in Socal. They do mail order and the tape is expensive (relatively). The 1/4" 9460 I have I got from a kite supply store called Hang-em High Fabrics, since closed.

If anyone wants the excel spreadsheet I used to make the cant curve, just pm me with your email address and I'll attach it.

Steve

Bill Fornshell
(bfornshell) - MLife

Locale: Southern Texas
Re: 3M 9460 on 05/21/2014 15:20:25 MDT Print View

Hi,

I have made a lot of gear using Cuben Fiber and never really used glue or tape, always sewed it. The only time I used one of the different glue products was for the neck on my Poncho / Tarp. I was having a hard time trying to figure out how to sew it so I used glue. That worked OK.

After reading this thread I called my local RS Hughes to ask about 3M 9460. They could sell me 9460 1" wide tape, one roll at a time, 6o yards for about $40.00. They also offered me a 3 yard sample to test with. I just received the 3 yard sample and now need to decide what I want to make with it.

Mario Caceres
(mariocaceres) - F

Locale: San Francisco
Polycarbonate for custom washers on 09/25/2014 22:48:08 MDT Print View

Thank you Steve for this great write up. I will start building my own Cuben Tarp soon and will follow some of the techniques presented in this post. As an alternative to the Flat Carbon piece you used in your tie outs, others may consider small pieces cut from Polycarbonate Sheets. They are very easy to work with (the thinner versions of Polycarbonate can be even be cut with some sturdy scissors, you can drill holes on them, etc) and they are super strong.

Here a 2”x1”x0.0625” (yes that is 1/16” thick) piece taking 50lbs of weight. I drilled holes for attaching the guylines about 1/2” from the edge. The holes did not stretch at all after lifting the weights.

1/16" thick Polycarbonate test

I got polycarbonate samples on my local Tap PlasticsTap Plastics store here in San Francisco. And I’m planning to cut some custom “triangular washers” for my cuben tie-outs.