Previously, we have done a tensile strength test on some of the most commonly used fabrics in the bag manufacturing industry, and we have received some very interesting results. (Please read The Fabric Strength Challenge for more information.)
From that test, we have learnt that fabrics like 600D Polyester and 1000D Nylon are indeed quite strong. 600D Polyester broke at 127.4N and 1000D Nylon broke at 291.7N. However, tensile strength is not the only thing to consider when determining the durability of a fabric, the other important consideration being abrasion resistance. Therefore, to follow-up, we have carried out an abrasion test this time.
The abrasion resistance test method we have used this time is the Martindale method (SATRA TM31-2003), with 12 kPa load, tested dry and under 25,600 cycles. The fabrics that we have tested this time are:
600D Polyester, which is the most commonly used fabric for backpack manufacturing.
500D Nylon, which is often called 600D Nylon.
1050D Nylon, which is often called 1000D Nylon.
Below is how the test looks like:
The test result is:
600D Polyester: Moderate abrasion after 25,600 cycles
500D Nylon: Very slight abrasion after 25,600 cycles
1050D Nylon: Very slight abrasion after 25,600 cycles
This is a very good result. After 25,600 cycles, which is a lot, 600D Polyester is holding pretty well. We can say that backpack made out of 600D Polyester should last for years under normal and fair usage.
The performance of 500D Nylon and 1050D Nylon are even better, the difference before and after 25,600 cycles is almost negligible, which is incredible. This is the main reason why these two fabrics are often considered as military gear grade materials.
The abrasion test above is a very good way to simulate the performance of the fabrics under normal and daily usage. However, we think this test is not aggressive enough for us to see the difference between some very tough fabrics. Currently, both 500D and 1050D nylon come up with very slight abrasion. We expect we will get similar results for Cordura which is supposed to be even stronger.
If you are interested to see a more aggressive fabric test, please check out a video done by Alabama Owens. He has done a very interesting Torture Test comparing 1000D Nylon vs 1000D Cordura Nylon. According to his test, Cordura did show that it was superior to regular 1000D Nylon.
Have you ever wonder why 600D Polyester is so popular even when it is not the strongest fabric out there? Why don't outdoor brands just use Cordura for all of their products? The answer is very straight forward. It is because 600D Polyester is only half the price of 500D Nylon; fabric such as 1000D Nylon and Cordura are even more expensive. So, from the costing point of view, 600D Polyester is a very good choice. Even though it is not the strongest fabric available, it is still a very tough fabric.
JanSport, for example, uses 600D Polyester for their best selling BIG STUDENT, SUPERBREAK BACKPACK & DIGIBREAK collections; while for their higher end collections such as RIGHT PACK , Nylon and Cordura are being used. All of their products are covered by JanSport's Lifetime Warranty, so they are all supposed to last for lifetime. Therefore, I think we can say that the real life difference between these few main fabrics might not be so significant after all; as they are all very strong fabrics.
There are actually many other factors that could affect the overall performance of a backpack. We have many ways to make a backpack stronger through different reinforcements and workmanship. We will cover that later on.