The question can I exploit the physics in wet felting has been running through my mind in the last few weeks. I think it was sparked by the fascinating TV series called from ‘From Ice to Fire’ . This made me start to recall the facts I learnt at a highly technical and fascinating felting workshop with Lisa klakulak .
Long before I was a felter I was an engineer working on chemical manufacturing processes. What you might ask has that got to do with wet felting . Well professionally as an engineer I was involved with changing the physical state of materials in an efficient and environmentally friendly way. By more fundamentally understanding the physics of the process we could become more efficient. As an example finding a way to keep the water flow turbulent to make the heat transfer more efficient and use less energy. Exactly the reserve of the principle of improving the aerodynamics of a car, in order to make it less resistance to the air and use less fuel. But exactly the same physics. The TV programmme ‘ From ice to Fire ‘ brought home to me that fundamental principles , works for everything . If we can only understand them. So why not felting. As a wet felters we are taking 1000’s of wool fibres and use water and soap to produce felt. What is the physics that determines how this process works is and what affects the efficiency and the resulting quality of the felt.
These samples were made following my workshop with Lisa. They all started as 40cm squares, all were felted completely by me using the same wool fibres , same water , same soap. The only different was the quantity of wool fibre. The larger the final sample the more wool fibre was laid out on the 40cm square and the less it was possible to shrink the sample in 2 dimensions. Why does this happen ?
These samples were made using a wide range of different wool fibres . With the same 40cm square starting point , same water , same soap etc. The only difference was the amount of fibre used. The final results all are the same. There is no difference in the ultimate shrinkage of merino and herdwick fibres, Jacob and Gotland, BFL and Shetland. Why does this happen ?
But there is something else happening .
I have only measured the shrinkage in 2 dimensions. Are all the samples all the same thickness. No they are not. This is very hard to measure. But there is no doubt , that the tiny red sample above is considerably thinner than the large yellow sample. Roughly if we measure the density as mass/ volume rather than mass / area , the wool fibres have ended up packed together just as closely in all these samples.
I postulate that wool fibres , like the universe must be governed by physics when we are felting. This fundamental is determining the maximum closeness of the fibres.
So what you are saying !
Well I think the more we can understand of the felt physics , the easy the feting process will become , and the better our control of our felt will become , the more predictable the outcomes will be and we will make higher quality felt. In other words we will be exploiting the physics.
If from the same the same starting point different wool fibres make the same felt . Their propensity to felt originally must be exactly the same.
If you want thin felt that has shrunk a huge amount in 2 dimensions lay out thinly. If you want low levels of shrinkage and heavy felt lay out thickly. Of course this is assuming you always felt as far as you can , which clearly we don’t always. But I fell is good to understand . Do you ?
So there are a few other questions I would like to answer . Maybe the fundamentals of physics help here.
Why does wetting out the fibres and leaving them to mature over night , make the felting process faster. ?
Why does using too much soap slow down the felting process?
Does different soap effect the felting process. ?
At what point in the process can you use hot water and how hot is OK.
Complicated , so complicated, I think now I understand the shrinkage, its time to think of an experiment to test one of my other questions.
GREAT POST click here to follow blog by email
Sue
12 Mar 2018This is great information. I’m looking forward to read what you find out with more experimentation re these other questions.
Teri Berry
18 Mar 2018What a great post Jane, I really enjoyed reading this, being a scientist (molecular biology) myself I am always looking for rational explanations for why things happen a certain way. I like your theory that there is a maximum density of fibres, they literally can’t get any closer together, hence the thickly laid sample are unable to shrink any further in 2 dimensions.
In answer to your questions at the end of the post:
I don’t think leaving the fibres to soak overnight makes the felting process faster, yesterday I made 2 identical pieces, one was wetted out before bed and the other this morning, they were rolled in the same bundle and treated in the same way, I could not see any difference in the speed or quality of the felting.
I haven’t tested whether too much soap really does slow down felting but I can see a theoretical argument that the excess soap might inhibit the cuticles on the fibres from locking together, it might act as a lubricant.
Personally I doubt different soaps will impact the felting process, to my mind they are just acting as a wetting agent. The one exception might be those 2-in-1 shampoos with conditioner, I wonder if they smooth the cuticles down so there are fewer available to lock with their neighbours?
Water temperature I have experimented with quite a lot. As I am sure you know, hot water is a bit of a no-no for nuno until you are sure the fibres have migrated through your fabric but for other work, once the surface design has been fixed with gentle rubbing (and hand-hot water), I use boiling water from the kettle if rolling in a bundle or add a little cold water so I can bear to touch it if I am massaging it. The hotter the water the quicker the wool will form a felt and full. I hypothesise this is because the hot water causes more cuticles to open up, if that is true, then the resulting felt should be firmer / better quality as there will be more links between each fibre and its neighbours.
Sorry, this comment is a bit rambling, you clearly found one of my soft spots! 🙂
jane_mercer
18 Mar 2018Many thanks Teri for your reply . I am fascinated to read the results of your experiments and hypothesis. I intend to experiment this week with soaking and I will let you know the results. The believe soaking will speed up the process as the wool will have absorbed more water and the cuticles will be more open. We will see !
duckshedfelt.co.uk
19 Apr 2018Enjoyed both of your comments – just a little comment from a non scientist – I like to lay out, wet down and leave to rest and soak in overnight. I then sponge out and rewarm in the microwave or with warm water – depending on where I am. I think rest for felt and rest for felt maker both essential LOL!
Harun's Physics Academy
28 Feb 2024I enjoyed both of your remarks. Just a little non-scientific comment: I like to lay out, wet down, and leave to relax and soak in overnight. I then sponge out and rewarm in the microwave or in reheat water, depending on where I am. I believe that rest for felt and rest for felt makers are both needed Great.
jane_mercer
28 Feb 2024Yes you are right. A rest is always good 😊