Whether you are by nature a planner or an improviser, you have probably scratched your head and pondered the question of how long a warp needs to be for a particular weaving project. There is no right answer – after all, how long is a piece of string? But there are ways to reach a good answer for whatever you are planning to weave.
There are two opposing things weavers are usually trying to avoid:
- Running out of warp before a project is finished. (Half a table mat, anyone?)
- Running out of patience or interest while there is still a lot of warp left on the loom.
In order to find the perfect warp length that balances these two risks, you need to spend some time thinking about what you want to weave.
So, what do you want to weave?
Suppose I want to weave a table runner. I know what table runners look like in general, but I need to pin down a few details about this particular table runner. It can be helpful to draw a rough diagram that shows the different parts of my table runner warp and how they might be used. I’ve used squared paper to make it a bit easier, but the sketch doesn’t need to be to scale.
This process forces me to answer some questions: do I want to weave a hem (like the sketch on the left) or leave enough yarn for a twisted fringe (like the one on the right)? How much sampling will I need? If I am not certain, then I may want to pick the option that gives me the most flexibility, i.e. allow enough warp for the longest version of my idea, even though I may not weave it. Or I may use the information in my sketches to help me choose the shortest version, which is likely to be the least expensive.
I can also see where there will be waste yarn, and think about ways to minimize this, e.g. through lashing on rather than tying on to the front apron rod. Looms vary a great deal in size and set-up, but the greatest waste is almost always at the end of the warp. Eventually, when the back apron rod is as close to the shafts as it can be and I can no longer open a big enough shed to force my shuttle through, I am going to have to stop weaving. The length of remaining warp from the fell of the cloth to the apron rod is mostly waste – the main exception is that I may be able to use some of it as a fringe on my last woven piece.
Once I have thought through this I should be able to put a rough number to each of the following
1. The total finished woven length including any samples (Woven)
2. The total finished unwoven length, e.g. fringes (Unwoven)
3. The amount of warp waste (Waste)
You may already have tired of this process and be impatient to get to the loom. By all means go ahead and wind a warp! However, for those of you who are willing to stay with me, there is another level of detail to consider.
Changes to the warp length
There are two stages in weaving that significantly change the length of your warp.
One is the weaving itself, through the process of take-up. Take-up is the name we give to the way that the warp gives a little and bends around the weft as we weave. This typically means that you “lose” between 5 and 10 percent of your warp as it is woven. Any unwoven parts of your warp – such as fringes – will be unaffected by this process.
The other is wet finishing, when the fibers themselves may shrink during the process. Your woven piece may lose another 10 percent of its length at this stage, although the exact amount of shrinkage will depend on the yarn you are using. Your whole finished piece, fringes included, will be subject to this transformation.
Rough and ready
To get a really accurate take on the percentages involved here, there is no substitute for sampling. However, for a rough and ready approach, let’s assume 10 percent loss at each stage — that is very likely to be an over-estimate and so you will be erring on the side of too much warp rather than too little.
So to find the total warp length we need to apply these losses to the three elements we identified above
- Woven x 100/90 x 100/90 (allows for take-up and shrinkage)
- Unwoven x 100/90 (allows for shrinkage only)
- Waste (no change)
Then add up 1, 2 and 3 and that is how long your warp should be. Now it’s time to choose some yarn!
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