0.8 MM POLYESTER PLISSÉ CORD BREAKING STRENGTH 0.20 kN
Thin cord for pleated and venetian blinds tends to look the same. This test shows how much difference diameter and core make.
The 0.8 mm polyester plissé cord breaks at an average of 0.20 kN, or 21 kg.
Thin cord is often lumped together: 0.8 mm is 0.8 mm, right? This test proves otherwise. This braided polyester cord reaches only 0.20 kN, while a similarly thin cord with a Dyneema core reaches 0.51 kN. Diameter alone says little without knowing what's inside.
Five measurements on this cord show little spread: the lowest measurement was 0.20 kN, the highest 0.21 kN. That's a spread of just 0.01 kN. However, the breaking strength curve was erratic during the test.
This may be due to the small diameter and the smooth outer surface of the cord, which can cause it to slip in the test clamps. We do not draw a firm conclusion from this.
0.8 mm polyester plissé cord: material and construction
This cord is made of polyester and braided. Polyester absorbs almost no water and therefore loses barely any strength when wet. The cord has no core made of a different material: it is entirely polyester, unlike variants with a Dyneema core.
How we test
The breaking strength tests are carried out in-house by Otto Tromm on a universal testing machine with a capacity of 50 kN.
For this machine, there are 2 sets of specially developed rope clamps, used depending on the diameter and material of the rope. These clamps allow rope to be tested without first having to be spliced.
All tests are carried out according to the guidelines of ISO 2307:2019. Among other things, this means testing is done 5 times and a test speed of 20 mm per minute is used.
Each rope is secured so that it is taut. No pre-tension is applied, since elongation is not measured in these tests.
For each test, 2 repetitions are filmed with a Sony camera on a tripod. In addition, the exact progression of the graph is recorded separately on video. This allows the tension progression and break behaviour to be matched precisely with the graph from the breaking test machine.
For each of the 5 tests, observations are also recorded in writing by the tester, documenting factors such as the degree of elongation, the way the rope breaks, and the loudness of the snap when the rope breaks.
Breaking strength test results
Five tests on the 0.8 mm polyester plissé cord show a consistent picture. The average is 0.20 kN, with a small spread of 0.01 kN between measurements.
The breaking strength curve was erratic during the measurements. This may be due to the small diameter and the smooth outer surface of the cord, which can cause it to slip in the test clamps. We draw no firm conclusion from this. For this diameter, 0.20 kN is sufficient on its own, but the difference with a cord that has a Dyneema core is clear.
How does this cord compare to a variant with a Dyneema core
The comparison below places this cord alongside a braided cord with a Dyneema core of the same thin size.
The cord with a Dyneema core reaches 0.51 kN, compared to 0.20 kN for the polyester plissé cord. That is a difference of 0.31 kN at the same thin size. The core makes the difference, not the diameter alone.
Conclusion: more than sufficient for pleated blinds
The 0.8 mm polyester plissé cord has a breaking strength of 0.20 kN, or 21 kg. That is more than sufficient for raising pleated blinds and venetian blinds or for craft projects, but clearly less than an equally thin cord with a Dyneema core, which reaches 0.51 kN.Otto Tromm tested the same thin cord five times and concluded that 0.8 mm still cannot support a zip line.