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Data > Shock Cords
Shock Cord Knots And Loops
Last updated 02/25/2004
Braided fiberglass
| Test Series # |
Type |
Source |
Description |
Peak Load (lbs) |
Other Picture |
| 1 |
Braided |
Mil Surplus |
DeH8 Loop Method |
540.189 |
Pic 1 |
| 2 |
Braided |
Mil Surplus |
DeH8 Loop Method |
703.591 |
Pic 2 |
| 3 |
Braided |
Mil Surplus |
DeH8 Loop Method |
739.787 |
Pic 3 |
These were shroud lines taken from a 60" Mil surplus chute. Pic 1 shows the longest cord, and how I had to extend the upper test fixture into the ceiling. The amount of cord threaded into itself was about a foot. I did this because the glass was "slippery". I did test it using the overhand knot method but the results were much lower. |
Small Braided Tubular Kevlar
| Test Series # |
Type |
Source |
Description |
Peak Load (lbs) |
Other Picture |
| Knotted 1 |
TKM |
Pratt Hobbies |
Overhand knots on each end |
261.473 |
|
| Knotted 2 |
TKM |
Pratt Hobbies |
Overhand knots on each end |
180.290 |
|
| Knotted 3 |
TKM |
Pratt Hobbies |
Overhand knots on each end |
271.299 |
|
| Knotted 4 |
TKM |
Pratt Hobbies |
Overhand knots on each end |
228.208 |
|
| RDeH8 Method |
TKM |
Pratt Hobbies |
2" / 3" inserted |
517.782 |
After Test |
In addition to showing the strength of this cord, this test shows the the RDeH8 method of securing Kevlar works well and shows that tying a knot to secure shock cords is a bad idea. (More RDeH8 coming) |
Joel Corwith's Knot test*
| Test Series # |
Type |
Width" |
Description or Source |
Peak Load (lbs) |
Elongation at break (in) |
| No Knot |
Tube Nylon |
3/8 |
|
357.482 |
|
| No Knot |
Tube Nylon |
3/8 |
|
348.225 |
|
| No Knot |
Tube Nylon |
3/8 |
|
350.149 |
|
| Surgeon |
Tube Nylon |
3/8 |
|
250.458 |
|
| Sheet Bend |
Tube Nylon |
3/8 |
|
274.765 |
|
| Sheet Bend |
Tube Nylon |
3/8 |
|
276.470 |
|
| Square |
Tube Nylon |
3/8 |
|
205.800 |
|
| Water |
Tube Nylon |
3/8 |
|
297.154 |
|
| Epoxy |
Tube Nylon |
3/8 |
|
43.603 |
|
* In all of the cases, The knot pulled tighter so elongation
data is irrelevant. The failure of the knots was the result of the knot
squeezing the cord while under tension.
Robert DeHate's Interwoven Shock Cords*
| Test Series # |
Type |
Width" |
Description or
Source |
Peak Load (lbs) |
Elongation at break (in) |
| 1 |
Tube Kevlar |
0.500 |
Pratt Hobbies TKL-C |
4071.464 |
Picture |
| 2 |
Tube Kevlar |
0.500 |
Pratt Hobbies TKL-C |
2867.800 |
|
| 3 |
Tube Kevlar |
0.500 |
Pratt Hobbies TKL-C |
3134.290 |
|
* In all three cases, the steel link broke before the shock cord. |
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