[Space] Tether string issue

David Stainton dstainton415 at gmail.com
Tue Apr 6 12:03:23 PDT 2010


Greetings,

For the ephermerial project I procured a tarred braided
(non-rotational) thick twine from:

Coast Marine
398 Jefferson Street
San Francisco, CA 94133
(415) 673-1923

However you may not need anything that heavy. I think the breaking
strength was around 900 pounds.
That is heavy stuff for such a breaking strength. These days I use
paracord for almost everything. It comes
in several different varieties. Paracord (parachute cord) has got a
core of straight fibers surrounded by a braided sheath. It's thicker
than kite string but thinner than the stuff I got from Coast Marine.
The kind I purchased from TAD Gear has a breaking strength of 550
pounds.

I know for sure that you can get paracord spools (of 100 feet for about $10) at:

TAD Gear
660 22nd St
San Francisco, CA 94107
(415) 318-8252

But also it is probably sold at various hardware stores: call them first.

I hope this helps!

~david

On Tue, Apr 6, 2010 at 11:50 AM, Christie Dudley <longobord at gmail.com> wrote:
> I don't think super-thin is important.  In fact, I personally think it's a
> detriment and it's a potential trip hazard problem that we'll have to solve,
> although I think we should do that regardless of the string we get.
> The primary problem is we know the string's strength.  NASA likes these
> numbers.  We've already given them the ones from the kite string Meredith
> found.  We would have gone with what we already had, if we could get numbers
> on it for NASA, but nobody could come up with that.
> The secondary problem is every bit of the weight of the string will be
> adding to the payload.  I personally don't think we'll be high enough that
> this'll be a problem, but it's not an insignificant concern.
> I really like that stuff that David got for Ephemerisle.  I've cc'd him here
> so maybe he might be able to share with us where he got it and how much it
> was.  IIRC, it was pretty pricey, but came on a big spool that we shouldn't
> need.
> Christie
> _______
> "We also briefly discussed having officers replaced by very small shell
> scripts." -- Noisebridge meeting notes 2008-06-17
>
> The outer bounds is only the beginning.
> http://www.flickr.com/photos/genriel/sets/72157623376093724/
>
>
> On Tue, Apr 6, 2010 at 11:27 AM, Brian Choate <brian.choate at gmail.com>
> wrote:
>>
>> Do we specifically want to have something that is very thin, almost
>> invisible to tether? If that is not super critical we have ~200 ft of cord I
>> picked up to use as the main payload tether.
>>
>> B.
>>
>> On Tue, Apr 6, 2010 at 9:12 AM, Christie Dudley <longobord at gmail.com>
>> wrote:
>>>
>>> You might also ask some of the knot/boat enthusiasts.  You're likely to
>>> get a lot more than you wanted to hear with advice, but they can probably
>>> point you in the right direction.  I think Shannon is on this list, but also
>>> David knows quite a lot about low-weight high-strength stuff and where to
>>> get it.  The stuff he got for Ephemerisle might do quite well for this
>>> application.
>>> Christie
>>> _______
>>> "We also briefly discussed having officers replaced by very small shell
>>> scripts." -- Noisebridge meeting notes 2008-06-17
>>>
>>> The outer bounds is only the beginning.
>>> http://www.flickr.com/photos/genriel/sets/72157623376093724/
>>>
>>>
>>> On Tue, Apr 6, 2010 at 12:31 AM, Michael C. Toren <mct at toren.net> wrote:
>>>>
>>>> On Mon, Apr 05, 2010 at 11:25:00PM -0700, meredith scheff wrote:
>>>> > oh no!
>>>> > I just got an email from the kite string place that i ordered out
>>>> > tethering
>>>> > line from- they are out of stock.
>>>> > does anyone know any local kite string resources?
>>>>
>>>> High Line Kites in Berkeley is awesome:
>>>>
>>>>    http://www.highlinekites.com/visit_us.shtml
>>>>
>>>> You'll have to wait until Thursday to see him, though.  I'd recommend
>>>> giving him a call at his office number tomorrow, to confirm he'll have
>>>> what you want, and see if he'll maybe let you come pick it up earlier.
>>>>
>>>> -mct
>>>> _______________________________________________
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>>>> https://www.noisebridge.net/mailman/listinfo/space
>>>
>>>
>>> _______________________________________________
>>> Space mailing list
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>>>
>>
>
>


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