Page 1 of 2 12 LastLast
Results 1 to 10 of 16
  1. #1
    Senior Member SC_Dave's Avatar
    Join Date
    Oct 2010
    Location
    Hickory, NC
    Hammock
    XLC 1.7 Double
    Tarp
    WB Superfly
    Insulation
    Incubator/Burrow
    Suspension
    Webbing
    Posts
    328

    Rip-Stop Nylon Strength

    Anyone know how many PSI rip-stop nylon will support? I googled but could not come up with anything definative. Thanks.
    David

  2. #2
    Senior Member DemostiX's Avatar
    Join Date
    Jan 2011
    Location
    Like Lewis & Clark: Wintrin' o/t Columbia again: PDX
    Hammock
    Clark w 2QZQ mod,Tropical, NX;Nano
    Tarp
    Clark micro
    Insulation
    Major down
    Suspension
    7/64 SK75 +strap
    Posts
    2,322
    Images
    13
    You'll find a Youtube of one of the boutique / cottage tarp or shelter makers comparing behaviors of cuben he tears at with an awl. The cuben comes in different weights. One punctures and rips. The other does not.

    No numbers. But, what this guy is showing is what matters. Not whether the fabric is strong enough to handle the full load of a 300 lb guy applied with his knee, but what happens when his 115lb girlfriend sits down just above the pointed end of a car key hanging from the carabiner on her belt loop.

    One number, not the right number, doesn't do it.
    Last edited by DemostiX; 06-30-2011 at 14:00.

  3. #3
    Senior Member Ramblinrev's Avatar
    Join Date
    Apr 2008
    Location
    Milton, PA
    Hammock
    Hennessey Explorer Ultralight
    Tarp
    Hennessey Hex
    Insulation
    HH Super Shelter
    Suspension
    ring buckle
    Posts
    7,945
    Images
    101
    Quote Originally Posted by SC_Dave View Post
    Anyone know how many PSI rip-stop nylon will support? I googled but could not come up with anything definative. Thanks.
    David
    You asking an incomplete question. What ripstop? There are a myriad of weights available. If you want to know the PSI what are you planning on doing with it. Warbonnet has a chart that gives recommended weights for safety with the various fabrics he offers. Most of us refer to that chart. PSI is not really a meaningful number for hammocks. The gathering in the hammock and the stretched areas are going to be different in that regard.

    Assuming you manage to keep from punching a hole in it the total weight is what you are going to want to know. If you punch a hole... all bets are off anyway.
    I may be slow... But I sure am gimpy.

    "Bless you child, when you set out to thread a needle don't hold the thread still and fetch the needle up to it; hold the needle still and poke the thread at it; that's the way a woman most always does, but a man always does t'other way."
    Mrs. Loftus to Huck Finn

    We Don't Sew... We Make Gear! video series

    Important thread injector guidelines especially for Newbies

    Bobbin Tension - A Personal Viewpoint

  4. #4
    Senior Member DemostiX's Avatar
    Join Date
    Jan 2011
    Location
    Like Lewis & Clark: Wintrin' o/t Columbia again: PDX
    Hammock
    Clark w 2QZQ mod,Tropical, NX;Nano
    Tarp
    Clark micro
    Insulation
    Major down
    Suspension
    7/64 SK75 +strap
    Posts
    2,322
    Images
    13
    Well, lets say you've got nothing to swing on to cross a crevass in an emergency but your rolled up hammock. A test of tensile strength.

    We go to
    http://www.engineeringtoolbox.com/ny...th-d_1513.html

    , and find that 1 yard of 1 1/8" nylon rope has a breaking strength of 28,260 lb and weighs 3 x .322lb = .966lb = 1 lb. (close enough) That's the tensile strength of 1lb of nylon strands.

    That's a full pound of it. We'll pretend our hammock is 1.9 ripstop and round up to 2.0 oz. How much does a yard of hammock weigh? If it were 1 yard wide, it would weigh that nominal 2 oz. How does that compare to the nylon rope, then, for breaking strength? Divide 1lb =16 oz by 2 oz = 8 and also divide 28,260 lb by 8 and get 3,500 lb.

    Of course, half the threads are running perpendicular to the load; who knows what they contribute to the hammock not breaking when you're swinging from it? Maybe nothing but adhesion. So, we'll discount them completely and divide 3500 by 2 = 1,750.

    Or was that hammock a GT Nano 7, which might be of 1.1 sil nylon. Better divide 1750 by 2, then = 875. Worse, the Nano 7 is short bugger, and you may drop in the crevass, but maybe not, because under load, the nylon hammock will stretch before breaking.

    Still, you wish you were swinging from one of Warbonnet guy's imports, which gives you greater length, even though, as 1.0 nylon, it may not be as strong. But, we've alread rounded 1.1 down. so 875 lb it is. Enough for (almost) 3 of the big guys who hang here all at once.

    Oh, the engineers derate the minimum breaking strength by a safety factor of 12 !!. That shrinks 875 lb down to 73 lb.

    Well, you can swing your 9 year old daughter across to safety without later facing charges of reckless endangerment. But for yourself: You've got a choice of facing the tiger alone, or knowing the load factor of 12 is conservative, and the hammock likely won't break.

    Error in original. I forgot that the hammock is not 1 yard wide. Typically it is, say 1.5 yards wide, so you'll be swinging from 50% more fabric and tensile strength than in the calcualations above. Now you can send your 110 lb bride safely across.
    Last edited by DemostiX; 06-30-2011 at 22:29. Reason: error in calculation

  5. #5
    Senior Member SC_Dave's Avatar
    Join Date
    Oct 2010
    Location
    Hickory, NC
    Hammock
    XLC 1.7 Double
    Tarp
    WB Superfly
    Insulation
    Incubator/Burrow
    Suspension
    Webbing
    Posts
    328
    Quote Originally Posted by Ramblinrev View Post
    You asking an incomplete question. What ripstop? There are a myriad of weights available. If you want to know the PSI what are you planning on doing with it. Warbonnet has a chart that gives recommended weights for safety with the various fabrics he offers. Most of us refer to that chart. PSI is not really a meaningful number for hammocks. The gathering in the hammock and the stretched areas are going to be different in that regard.

    Assuming you manage to keep from punching a hole in it the total weight is what you are going to want to know. If you punch a hole... all bets are off anyway.
    I apologize for not forming my question properly and not being familiar with the proper terminology. Please excuse my layman's attempt to gather knowledge. I just bought some rip-stop nylon at the fabric store to make a hammock chair and was trying to determine if it would hold me, that's all. I don't know the weight of the fabric, no big deal.
    David

  6. #6
    Senior Member traftonm's Avatar
    Join Date
    Sep 2009
    Location
    Concord NC
    Hammock
    WBBB
    Tarp
    DIY Cuben fiber
    Insulation
    DYI UQ/TQ Down
    Suspension
    whoopee sling
    Posts
    115
    DC Dave, Rip stop is very strong in any wt. If you do a gathered end chair hammock I can't think of any reason that it would not hold you., evn if it were 1.1 wt.

  7. #7
    Senior Member SC_Dave's Avatar
    Join Date
    Oct 2010
    Location
    Hickory, NC
    Hammock
    XLC 1.7 Double
    Tarp
    WB Superfly
    Insulation
    Incubator/Burrow
    Suspension
    Webbing
    Posts
    328
    Quote Originally Posted by traftonm View Post
    DC Dave, Rip stop is very strong in any wt. If you do a gathered end chair hammock I can't think of any reason that it would not hold you., evn if it were 1.1 wt.
    Thanks very much. The lady at Hancocks had no clue if it was 1.1 or 1.9 so I don't know....... I'll give it a try.
    David

  8. #8
    Senior Member DemostiX's Avatar
    Join Date
    Jan 2011
    Location
    Like Lewis & Clark: Wintrin' o/t Columbia again: PDX
    Hammock
    Clark w 2QZQ mod,Tropical, NX;Nano
    Tarp
    Clark micro
    Insulation
    Major down
    Suspension
    7/64 SK75 +strap
    Posts
    2,322
    Images
    13
    Please accept my apologies for teasing. But, read the end of Ramblinrev's first commentt again: all bets are off if you puncture it. The distributed load on many fabrics is not so great as to burst it, a test of the tensile strength of the fibers. We take it for granted. But only as long as there are no rips, tears, punctures, or weak points.

    Weak points? There's the rub. The thinner the fabric, all things equal, the more likely it is to be dangerously weakened by rubbing: abrasion. So, stay away from abrasion, and thin nylon will be as good as thicker. But, thicker will be tolerate your load longer, if abraded.

    You could determine the weight of what is on offer if your scale will resolve to +-3 grams, about 1/10 oz. . 2/3 yard off the bolt will come to close to a square yard. Measure and do the exact arithmetic, and allow for .1 -.4 oz per yard for coating, if you suspect it has been treated. You can make snake skins or bags from the sample.

  9. #9
    Senior Member SC_Dave's Avatar
    Join Date
    Oct 2010
    Location
    Hickory, NC
    Hammock
    XLC 1.7 Double
    Tarp
    WB Superfly
    Insulation
    Incubator/Burrow
    Suspension
    Webbing
    Posts
    328
    Quote Originally Posted by DemostiX View Post
    Please accept my apologies for teasing. But, read the end of Ramblinrev's first commentt again: all bets are off if you puncture it. The distributed load on many fabrics is not so great as to burst it, a test of the tensile strength of the fibers. We take it for granted. But only as long as there are no rips, tears, punctures, or weak points.

    Weak points? There's the rub. The thinner the fabric, all things equal, the more likely it is to be dangerously weakened by rubbing: abrasion. So, stay away from abrasion, and thin nylon will be as good as thicker. But, thicker will be tolerate your load longer, if abraded.

    You could determine the weight of what is on offer if your scale will resolve to +-3 grams, about 1/10 oz. . 2/3 yard off the bolt will come to close to a square yard. Measure and do the exact arithmetic, and allow for .1 -.4 oz per yard for coating, if you suspect it has been treated. You can make snake skins or bags from the sample.
    No need for appologizes. Thanks for the info. Just want to be sure I am using the correct materials.
    David

  10. #10
    Senior Member Ramblinrev's Avatar
    Join Date
    Apr 2008
    Location
    Milton, PA
    Hammock
    Hennessey Explorer Ultralight
    Tarp
    Hennessey Hex
    Insulation
    HH Super Shelter
    Suspension
    ring buckle
    Posts
    7,945
    Images
    101
    I was interested in what the PSI number would give you for your purposes. That is obviously going to change by the weight of fabric. For example with a water carrier it could be very helpful to know the PSI so you could have some idea of the workable capacity. I am sure there are other projects where that would be a useful number. As far as hammock bodies I don't think it would tell me much. Trying to convert the PSI number to a usable measure for the hammock would totally max my brain cells.

    If I sounded flip or off putting I apologize. I really wanted to know what the usefullness of that figure was going to be.
    I may be slow... But I sure am gimpy.

    "Bless you child, when you set out to thread a needle don't hold the thread still and fetch the needle up to it; hold the needle still and poke the thread at it; that's the way a woman most always does, but a man always does t'other way."
    Mrs. Loftus to Huck Finn

    We Don't Sew... We Make Gear! video series

    Important thread injector guidelines especially for Newbies

    Bobbin Tension - A Personal Viewpoint

  • + New Posts
  • Page 1 of 2 12 LastLast

    Similar Threads

    1. Cheap rip stop nylon 1.1
      By Bushwhacker in forum Fabrics
      Replies: 19
      Last Post: 02-26-2014, 12:01
    2. Rip-Stop Nylon
      By Laochri in forum Fabrics
      Replies: 7
      Last Post: 05-27-2012, 17:05
    3. Rip stop nylon Question?
      By grantizzle in forum Do-It-Yourself (DIY)
      Replies: 10
      Last Post: 11-27-2011, 22:06
    4. This is how I cut Rip-Stop Nylon
      By chickenwing in forum Do-It-Yourself (DIY)
      Replies: 28
      Last Post: 09-02-2011, 17:20
    5. Rip Stop Nylon
      By restlesss in forum Do-It-Yourself (DIY)
      Replies: 4
      Last Post: 02-22-2010, 22:23

    Tags for this Thread

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •