3 ms·

Well, neither wikipedia nor the linked article say why zip ties aren't used. I don't know what material the lacing is made from, but unless it is a natural thre

by kghose 14y ago

Well, neither wikipedia nor the linked article say why zip ties aren't used. I don't know what material the lacing is made from, but unless it is a natural thread I'm sure zip ties can be made from that material. It might be that tension (which is what I worry about when I zip tie delicate things like optic fibre) is better controlled in hand tied knots, but zip ties can be tied pretty precisely.

ars 14y ago
"but unless it is a natural thread I'm sure zip ties can be made from that material" A zip tie requires a different combination of compression strength, tensile strength, and elongation stability compared with lacing. So the materials are not interchangeable. Also, individual fibers bundled into a cable is MUCH MUCH stronger than the exact same amount of material as a single homogeneous cable. And individual fibers can handle flexing and vibration far far better than a single large strand.
ChuckMcM 14y ago
See this: http://code541.gsfc.nasa.gov/Uploads_materials_tips_PDFs/TIP%20012R.pdf http://code541.gsfc.nasa.gov/Uploads_materials_tips_PDFs/TIP... for acceptable lacing materials. Zip ties are 'quantized' by the ratchet, so you can find an 'optimum' tension point that is between two ratchet points. Which doesn't happen with laces. And for threads (like kevlar thread) it doesn't have the compression strength to be good zip tie. There is a lot of information about what NASA considers to be good and not good wrapping techinques here: http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/401%20General%20Requirements.html http://workmanship.nasa.gov/lib/insp/2%20books/links/section... Also they mention out gassing which is something I completely missed, plastic zip ties have that issue as well. Any void in the zip tie also becomes a real problem in vacuum.
rhizome 14y ago
As a matter of fact, the article goes into some detail about both why zip ties aren't used and what the lacing might be made of.

by kghose 14y ago

ars 14y ago

"but unless it is a natural thread I'm sure zip ties can be made from that material" A zip tie requires a different combination of compression strength, tensile strength, and elongation stability compared with lacing. So the materials are not interchangeable. Also, individual fibers bundled into a cable is MUCH MUCH stronger than the exact same amount of material as a single homogeneous cable. And individual fibers can handle flexing and vibration far far better than a single large strand.

ChuckMcM 14y ago

See this: http://code541.gsfc.nasa.gov/Uploads_materials_tips_PDFs/TIP%20012R.pdf http://code541.gsfc.nasa.gov/Uploads_materials_tips_PDFs/TIP... for acceptable lacing materials. Zip ties are 'quantized' by the ratchet, so you can find an 'optimum' tension point that is between two ratchet points. Which doesn't happen with laces. And for threads (like kevlar thread) it doesn't have the compression strength to be good zip tie. There is a lot of information about what NASA considers to be good and not good wrapping techinques here: http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/401%20General%20Requirements.html http://workmanship.nasa.gov/lib/insp/2%20books/links/section... Also they mention out gassing which is something I completely missed, plastic zip ties have that issue as well. Any void in the zip tie also becomes a real problem in vacuum.

rhizome 14y ago

As a matter of fact, the article goes into some detail about both why zip ties aren't used and what the lacing might be made of.