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Posted on Sat, 14 September 2013
I often get asked about treatment, so rather than entirely re-invent the wheel, I have added to and adapted a rather good post by Kernunos.
Boiling
Methods:
Shortest boil time: None
Longest boil time: 8 hours
Pros: longer boil makes the rope softer and smoother
Cons: longer boil makes the rope weaker and darker.
Traditionally, rope would be boiled in a pot or pan. However, kitchen automation gives us the option of clothes and dish-washers. I prefer the latter as rope can simply be laid in the machine and comes out untangled. Using a washing machine is more aggressive and can result in horrendous tangles unless the rope is 'chained' first in a sort of knitting stitch (Dragon rope). It is also wise to put it in a lingerie bag or pillow case to keep the fibres out of the filter.
Summary:
* Boiling leaches colour out of the rope into the water making "rope tea"; this gets as dark as it is going to get after about 15 minutes. After that it begins to darken the rope. The colour change isn't really noticable until after an hour of boiling. It is solidly burlap brown around hour four. The Akechi Denki Nameshi recipe specifies around 3 minutes for loose laid asanawa.
* Rope gets weaker as it gets softer from longer boil times. There seems little difference in texture between fifteen minutes and two hours. After more than six hours, the rope can become seriously weakened.
* The looser the lay of the rope, the less time is required.
* Boiling rope opens up the lay and can make it prone to untwisting and 'high-stranding', i.e. going out of balance and kinking. I usually skip the boiling stage for very loose laid rope, e.g. my old style Asanawa.
* Conditioner will fluff the rope up. I personally dislike the result, preferring my rope to stay more compact.
Conclusion:
* More than fifteen minutes of boiling seems to be overkill, especially for loose laid rope.
Stretching
Methods:
* No stretching while drying
* Manual retensioning while drying
* Stringing it up between ratchet straps and keeping constant tension for the drying process.
* Adding a weight to the rope, e.g. a weighted bucket attached at the mid point.
No stretching while drying resulted in a loss of about 10% of total length and a thicker rope. This is limited and can eventually stretch back out. Tensioned methods resulted in no noticeable loss and help retain the original diameter.
Clifford Ashley in "The Ashley Book of Knots" cautions against excessive stretching while wet as it damages the ropes. This was not covered in these tests but seems a reasonable hypothesis. Hence using the least tension needed to preserve length seems to be in order.
All methods begin with boiling then stretching/drying. There is disagreement over whether singeing or conditioning should come next. I tried both.
Singeing is done with a propane torch or gas hob. The former is fast but easy to damage the rope, so the less aggressive gas hob is easier. If you don't have one, try a gas camping stove. Don't use sources such as candles as they can leave the rope black and sooty.
I prefer to oil first then burn off as it helps 'wick' the oil into the rope. It also means that you don't end up raising more fluff when you apply the oil.
Conditioning:
* Complicated and probably most subjective portion of the process.
* Oils used: Tsubaki, bayu, olive, mineral (pharmaceutical grade), mink or hemp oil, bees wax and Shea butter
Once order was established picking the right oil is probably a matter of personal taste. Some notes:
* Applying the oil with a rag can make it difficult to avoid uneven application. Often the first few inches have much more oil applied than the rest of the rope. This can be overcome by varying the pressure, rotating and turning the cloth and making sure it is evenly absorbed before you start.
* Stiff products (Shea butter, beeswax, mink oil) require more care to not over apply. Pharma grade mineral oil is very thick and therefor unpredictable.
* Beeswax can be applied before boiling or it is too waxy and sits on the surface of the rope. I prefer to apply it after tensioning and drying by drawing the rope between two blocks. I then put the rope in a microwave for just about a minute or a little more to melt it in; with jute, it comes out delightfully creaky.
* Kernunos says that Shea butter and mink oil both give a visual as well as tactile clue as to application density that other oils do not. I cannot comment having only used hemp, almond and tsubaki oils and beeswax.
* I suspect any food, cosmetic, or pharmaceutical grade oil that will not go rancid or harden will do the job, pick one you like. Traditionalists will usually go for beeswax, tsubaki oil or bayu.
Rubbing, petting, pulling through a karabiner, playing with, etc. the rope is part getting to know it, part checking for inconsistencies. Of course, nothing beats using it.
No doubt somebody somewhere has the perfect recipe on an ancient scroll given to them under an oath of secrecy by the grand nawashi who sits atop Mt Fuji ;-)
I have posted a chapter from my tutorial DVD, which not only shows how to treat rope but also explains a lot about chosing and storing it.