Ultralight bell tent pitched with ground pegs around the base and double guy ropes that are held down with a single peg.

Is nylon or polyester cord best for backpacking tents?

Nylon and polyester cords both have different properties that can be exploited with backpacking tents.

Introduction

For many years I have used nylon cord instead of polyester when making DIY pyramid tents with short walls (bell tents). Covid restrictions have restricted my activities and so allowed me to implement a crazy idea of making and testing such tents with breathing polyester as an alternative to silnylon. They have proven to stay dry and taught during cold wet nights, have much less condensation and dry quickly for early morning backups. I favour pyramid style tents for their simplicity, efficiency, versatility, snow shedding and strength.

Could an uncoated polyester tent made from ‘umbrella fabric’ beat the dreaded condensation problem of my single skin silnylon tents? “YES”

I am currently finishing a larger square pyramid that has a large vestibule or beak on the entry side to make it more spacious, improve ventilation and be more functional for wet weather entry and snow camping with a tent stove.

The pyramid tent with a vestibule showing the open door and netted window.
The pyramid tent with a vestibule showing the open door and netted window.

With or without a vestibule these tents require numerous guy out cords to provide stability. “They also, unfortunately, trip up nocturnal visitors, but luminescent markers on the pegs can aid the unwary.” Over the years I have made some small innovations to make these pesky cords easy to manage and to be free of tangling while being left permanently attached to the tent. I have even put bungee tension adjusters in the lines.

Ultralight bell tent pitched with ground pegs around the base and double guy ropes (nylon cord) that are held down with a single peg.

The peg out tabs and guy out cords are designed to function with a minimum number of formal DIY ultralight titanium pegs. Some or all of these pegs can be substituted with simple sticks. “Where possible, I use sticks, as the small pegs are very easy to lose. I carry one concrete nail to make pilot holes in hard or rocky ground if required.”

Ultralight titanium tent pegs. The pegs are made of 2 and 3mm diameter hard titanium alloy and made in various lengths to allow for variations in soil penetration characteristics. They include luminescent markers to help reduce losses. They also mark pegs at night and retain the peg on the guy rope. Heating the titanium to red heat at the bending point, before bending, is required to prevent brittle fracture as the wire is bent. The single large spike for making pilot holes. It is made from a ‘concrete nail’.The loop under the head of the nail can be used to extract the nail (with a suitable stick) and also makes it more visible to prevent loss. These pegs engage with extra loops of nylon cord that are attached to the tiny and numerous tie out tabs. This allows thick sticks to be used as pegs when snow camping.

Furthermore, the use of sticks is indispensable when camping amongst trees on deep snow. Having cord loops tied to the peg out tabs makes the use of thick stick easy, Alternatively, DIY ultralight snow anchors can be used if one must camp above the tree line on snow. The adjustable toggles (shown in the photo below) can be lodged in the same cord loops before tensioning.

Sewn snow anchor bags (4g) made from old discarded polyester tent fabric. When filled with snow and buried they make excellent deep snow anchors that work well when there are snow melting conditions. The cord lock on the nylon cord can be toggled into the cord loop on the tent tab so that can be adjusted to provide suitable tension.
An ultralight tent with an ultralight stove on a bush pole that is driven into the snow beside a snow pit. The ‘walk-in-entrance’ with snow steps down to the snow pit provides convenient and safe entry to a palatial heated tent. This 1.3kg backpacking load provides cooking, snow melting, comfortable seating and full standing room for a group of skiers when they have run out of turns or are beaten into submission by the elements. “Only sticks have been used to peg down and guy out the tent. The nylon guy out cords wraps around the pegs. The wood peg hold much better than lightweight metal pegs can.”

The one remaining issue with the nylon cords (cheap bricklayer line) is the wet/cold stretching as described in the polyester/silnylon tent comparison. Consequently, this post is about my experience with the use of a very similar alternative polyester cord which is also a bricklayer line and also equally cheap.

For those who are interested, I am also doing accelerated polyester ageing testing of my favourite tent-making fabrics and cords. So far they are all doing well after survival for one summer and we now head into winter.

Test strips of polyester umbrella fabric, silnylon nylon cord and polyester cord that are being exposed to the elements to observe their relative decay with time.

Nylon or polyester- relative properties

Nylon. Nylon is hydrophilic and stretches considerably when it becomes cold and wet and it does this surprisingly even when it is sealed with silicone rubber (eg silnylon). While the silicone rubber is hydrophobic to liquid water it is highly permeable to water vapour. This accounts for its abysmal performance in wet cold weather camping if the tent pitch is not continually adjusted.

Polyester (front) and silnylon (rear) tents after a night of steady rain. The silnylon tent has gone quite saggy. They were pitched equally tightly during the afternoon and both will look equally good after drying in plentiful sunshine.

Polyester. Polyester on the other hand is hydrophobic and very dimensionally stable whether it is dry and warm or cold and wet. The highly hydrophobic nature of polyester means that it can provide perfect rain protection for tent occupants without the need for any further waterproofing.

This also means that the fabric remains permeable to water vapour and the tent can breathe or permeate moisture through to the outside and greatly reduce the condensation in the inside of the tent. Its hydrophobic properties make it much quicker to dry and de-ice for cold morning pack up when out on the trail and moving daily. “The warmth of cooking breakfast inside the tent can greatly accelerate the residual drying.”

Polyester guy cords. Unfortunately, it took about 40 years to go against the flow and make and test my polyester tents, so I was determined not to take so long to find the ideal polymer for my guy cords. Polyester cords should eliminate wet/cold stretch in the many long guy cords. would be beneficial for the same reason as it is for the tent fabric. Also, if the wet/cold stretch is negligible for both the tent fabric and the cords, it should mean that I will no longer need to have my bungee tension adjusters. Their removal will also make the guy lines lighter and simpler. “They will also be much less tanglesome when the tent canopy is hung up to dry completely in the sun or a breeze.”

Nylon or polyester cord differences.

At first, the two types of cords looked so similar that I thought that I might get them mixed up. I knew that there were burn tests to fall back on. Anyway, as soon as I started to work with this new cord I knew they were so different that I would never get them mixed up.

  • Polyester unravels quickly when cut, so much so that it is impractical to cut without using a melting method. Even if using a hot knife to cut a single cord, bundles of fibres can unravel, so flame cutting is better as it fuses a wider band of the cord as the breaking point is made.
  • Nylon can easily be tied with secure simple knots, but the same knot may slip more easily with the polyester.*
  • They both seem to be adequate with regard to resisting extended exposure to UV radiation and the elements.

Note*: Interestingly, when I have impregnated nylon cord with silicone rubber to see if I could waterproof it, it becomes quite slippery and many knots that would normally hold will not hold.

These differences mean that I will continue to use both nylon and polyester. Polyester will be used for the long guy lines to eliminate stretch and I will suffer the more complex knot such as bowlines for their attachment.

I fix many small cord loops to the small sewn tie out tabs in the tent seams. These are designed as sacrificial and replaceable ‘break points’ to protect the embedded tie out and peg out tabs that are sewn into the tent seams

They become the easy attachment points for the guy lines, metal tent pegs, stick substitutes and snow anchors. For these, I use nylon because of the ease of knotting and the minimal stretch involved.

Readers might reasonably ask why not tie the cords directly to the sewn tie out tabs? So I should also explain a little more. These tabs are very small and numerous. All my pyramid tent designs have a bell wall, but the same tent is designed to be pitched low in what I call survival mode as a pure pyramid, with the bell wall becoming a large additional snow skirt. This means that some tie out tabs need to function as both guy out and peg down points. The small attaching loop allows for this. Also, the pegging driving action can abrade the cord and a contingency for quick and easy replacement is prudent. “Much easier than replacing a sewn tab in the bush or snow.”

Ultralight tent pitched low (foreground) in preparation for a big overnight blow. The guy out point that would normally be on the top of the bell wall has become the snow peg out point.

Conclusion

Both nylon and polyester cords are cheap and abundantly available as bricklayer lines and are UV stable. The nylon is much easier to cut and form knots in for small components that will not be affected by stretching. Polyester is more difficult to cut and knot but will be superior for long guy lines where wet/cold stretching will impair the tent pitch.

Tim

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