Sterling Rope Factory Tour

Article and photos by vegastradguy.

Sterling Rope J. Wilder Sterling Rope.

For a while now, I’ve been wanting to get out to some of the manufacturers of climbing gear and tour their factories- but, living on the west coast keeps me sort of stranded when it comes to that as most folks seem to make their stuff so far away! Luckily, a close friend’s wedding allowed me to schedule some time in the Boston area last week- one day of which was spent in a little town called Biddeford, Maine about an hour and a half north and two states away at the Sterling Rope facility. John Branagan- the Outdoor Products Manager for the company took a couple hours out of his day and took us on a tour of the plant- showing us how ropes are made, start to finish, their drop test room, and finally, the beehives!

After meeting some folks, John took us down to the factory- housed in a building at least the length of a football field, and probably as wide. As we headed down to the floor, I asked JB if a rope factory tour was like a chocolate factory tour- at the end of the tour, the chocolate factory gives you free chocolate- so, it stands to reason that at the end of the rope factory tour, perhaps some free rope might be offered to folks taking the tour. For some reason, he looked at me like I was that kid riding the short bus and then handed me some eye protection and we headed onto the factory floor.

J. Wilder

The process starts with spools of long flat nylon yarn that are delivered to the factory and will be turned into all of the different ropes that Sterling makes. They come in two types- white core yarns and colored sheath yarns. Both types go through a similar process before they are joined at the rope making machine itself. It starts with the first twist- either a ‘S’ twist or a ‘Z’ twist (basically a left and right twist). This is done by twisting a number of yarns together to make a larger, twisted yarn- this number is determined by the rope being made. Also at this point, the core yarns are coated with Sterling’s dry treatment before the first twist is made- ensuring that the core’s treatment covers every inch of yarn.

During this process, the tracking process also begins- every yarn is tracked through the entire process. The small yellow tag on the end of your Sterling rope contains information that allows Sterling to track that rope all the way back through the entire process to the original yarns. This is especially important- recently Maxim had a recall and their tracking process was key in finding out that it was the original product, not their process, which was the cause for it. This is also a good spot to mention the human touch- while the spinning and braiding of the rope is all done by machine, there are people monitoring every machine and doing all of the prep work for each process. Also, every machine is equipped with a monitor that shuts it down instantly if anything is amiss- all of which keeps every rope flawless in terms of safety and quality.

J. Wilder

The next step in the process is to create the core strands that will actually make the rope. A number of different twisted yarns (‘S’ and ‘Z’ yarns), balanced to prevent the rope from twisting and spinning on you when you’re rappelling on it, are combined to create the core strand (pictured above). These strands are wound onto spools and then go through a proprietary process to get them ready for the autoclave- the big shiny machine in the factory that uses steam and heat to set the yarn- think of shrinking a wool sweater- it’ll stretch, but it always returns to the smaller size- this is basically what the autoclave is doing to the nylon.

It's so big and shiny!!!! J. Wilder It's so big and shiny!

Once the steaming is complete, the strands are now prepped for actually being braided into rope. The core strands are once again wound onto spools and the sheath strands (which also went through their own proprietary autoclave process) are wound onto the bobbins that will go into the braider later on. This process is, like most of the others, mostly automated but a human is there to monitor the machines for any problems. The bobbin spools are wound at high speed from the strand spools, and when they are full, a machine automatically stops the winding, slices the strands, ejects the full bobbins, and then loads empty bobbins and begins the winding process over again.

The bobbins visible are full and are about to be cut- the new empties are visible on the right. J. Wilder The bobbins visible are full and are about to be cut- the new empties are visible on the right.

At this point, I should stop to say that I wish I could have recorded a movie for parts of this- the pictures don’t do it justice in terms of the speed all of this happens. Everything is done at a very high rate of speed- bobbins are wound in just a few minutes- and they contain enough yarn to make 800m of rope!

Finally, the strands are ready to be turned into rope. Workers on the floor take the ‘recipe’ for each rope and go get the appropriate bobbin colors and amounts and load them into the braider, as well as the appropriate number of core strands. The core strands are fed up through the center of the braider and then the sheath yarns are wound into place. Once everything is set up, a second worker will go over the firsts work to ensure that everything is good to go and they press go and the magic begins!

the Fire Ion being braided- so pretty!! J. Wilder The Fire Ion being braided - so pretty!

The machines work at a fairly constant rate of speed and each one can produce as many as 10-15 ropes a day- this of course varies by what goes into the rope. A bi-color rope- one where they have to change the bobbins every so many meters- can take longer because the machine has to stop. Also, a much thicker rope- like some of their rescue lines- gets braided much slower simply due to the size. Sterling didn’t mention the number of machines on the floor- but I would guess somewhere near 50 or so.

As the machine braids the strands into rope, it then feeds the rope into a large barrel. They change the barrel with each run of rope (machines can be changed easily from rope to rope- so a machine making a Marathon rope today might be making a Kosmos tomorrow) and then the barrel is moved down to finishing for final processing.

Up to 800m of line can be coiled into a barrel like this... J. Wilder Up to 800m of line can be coiled into a barrel like this...

Between the barrel and coiling comes the dry treatment on the sheath if the rope calls for it. This is a double treatment of the sheath that is proprietary- but I can tell you that each rope goes through it twice to ensure total coverage of the sheath fibers before being sent to final coiling.

Putting the finishing touches on a freshly braided line… J. Wilder Putting the finishing touches on a freshly braided line.

This is the part of the tour that surprised me the most. All Sterling ropes are coiled by hand straight from the barrel. The ropes are run up through a couple of carabiners hanging from the ceiling, and then through a rope length counter (like at Home Depot), through a workers hand, and onto a powered coiler (like those grey hand crank ones at Home Depot- only with a motor attached to a foot pedal). Every meter of rope runs through someone’s hand before going into a coil. This is final inspection- to make sure that nothing slipped through the system. From here, they are labeled and bagged and readied for shipping out to your local gear shop.

Of course, the rope process isn’t the only thing that takes place at the Sterling factory- lots of other things are done here as well. Sterling also has a section of the factory where they sew various things, including their famous Chain Reactor, daisy chains, and other things like sewing loops onto the ends of their industrial ropes. In addition to the sewing room, they also of course have a testing facility which houses the drop tower.

This big blue contraption is the drop tower- where the company tests its ropes before (and after) sending them off for UIAA certification. Sterling actually tests all of its products regularly to ensure quality and to learn more about the ropes behaviors to improve future products. In the photo above, notice the yellow portion of the tower. That’s where the rope is secured over the simulated carabiner. The red girders above is where the other end is dropped from (the weight is not pictured- it was on the bottom of the tower). I was hoping to see some drop tests while I was there, but alas, time was against us- so, no rope breakage photos!

On another note, you might have realized by this point that there is probably a fair amount of waste from the rope process- scraps, splices (its more efficient to splice the cores and sheaths than to rethread the braiders), shorts, etc, etc. One great thing about Sterling is that not a single scrap of waste from the process goes into the trash- it all goes into their recycling program. They had a HUGE box- probably 5 feet square and just as deep, about half full of scraps and waste- all of which was headed to the recycling center with the ropes sent in from around the country. All of this gets pelletized and made into things like sunglasses, childrens toys, etc- anything that can be made with pelletized nylon. Of course, I would be remiss to not put the Recyling info here for those folks who don’t know about this program- instead of throwing away your old rope, please send it to Sterling- doesn’t matter who made it or what condition its in- send it back and do something good for the planet. Send old ropes to: Sterling Rope Co. Attn: Rope Recycling 26 Morin Street, Biddeford ME 04005-4413.

Ropes and honey- all that's really important in life! J. Wilder Ropes and honey - all that's really important in life!

One other thing I wanted to mention is that one of the folks at Sterling is an avid beekeeper, and recently, they brought some colonies down to the factory to add to the landscaping around the front. At any rate, the company now makes its own honey right out front- and if you’re nice and ask politely, they might even give you a small container of it! The hives are located just to the left of the front of the building, surrounded by dozens of flowering plants to keep them happy.

So, the tour was over, and of course I drooled all over the stacks of pretty new ropes at the staging side of the factory, and of course I asked for one, maybe two new ropes. JB promptly directed me to the nearest gear store to make my purchase, but to his credit he did offer me some chocolate.