Dyeing a wool felt hat

Wool is amazing! So are microwave ovens. Read on...

I've recently been experimenting with dyeing wool felt to get a colour that a client has requested, that I could not easily obtain here in Canada (not without much expense in any case!). I did a lot of online research before I began to avoid any mishaps, and thought I'd share my results here.

My client asked for a hat in a particular shade of grey. Dark charcoal grey to be more precise. Searching both in shops and online didn't turn up anything suitable, but I did find a beautiful dove grey wool felt capeline that I thought I would try dyeing.

Most of my experience with dyes was at Nottingham Trent in both the costume and fashion departments, where I used Dylon Multi-Purpose, thankfully readily available here in Ontario and not too expensive. I purchased a small sachet of ebony black, and set off to do some testing.

My thoughts before beginning were that the dye would need to be hot and that heat would shrink the wool felt capeline. I envisaged a little doll sized hat emerging from the dye bath! I mixed a small amount of dye in a plastic cup and cut several slivers of felt from the edge of the brim for sampling. I kept one plain, so I knew how far the others had gone.

What I found most interesting was how the felt reacted under water, both hot and cold. The hat must have had some sort of treatment embedded in it for it didn't absorb any water initially. I tried first with cold, then with warm, and finally needed hot (as hot as I could touch) to get it to take. The felt immediately became lovely and soft and pliable, and much thicker - obviously having absorbed the water, but also because of the reaction I knew would take place within the fibre itself.

Illustration showing the barbs and how they grip.

The wool fibre, under a microscope, is scaly and textured. The little scales or barbs are what makes wool able to be felted, as they grip each other when rubbed together. Adding water and heat aids the process. Adding soap makes it work even better. How? The barbs of the wool fibre are slicked down when oil and grease are present, making the fibre smooth and slippery and it won't felt. The soap acts to take out every last little bit of oil, thus improving the felt-making process. How do I know? Its all in this wonderful 150 year old book named 'A Treatise on Hat-Making and Felting' published in 1868. A fascinating read if you like getting know how things work, especially hat materials!

Science bit over, now you know why I was having fun just playing with the felt in the water! I dipped one of my wetted sample slivers in dye to see what would happen. The dye was hot, nothing shrank, and my felt went a little darker. Not a lot. I left it for 2 minutes. Rinsed it, dried it. Only barely a hint of a shade darker. I dipped it for 20 minutes. Same thing, a little bit darker still, but nothing dramatic. To make sure it was really dry, I put the piece in the microwave. One of the dye labs at NTU had a microwave for students to quickly dry their samples, so I supposed mine would serve the same purpose. It did! And what fun - not only was it dry but it was fat and warm and squishy.

I decided to leave that dye sample in the pot for 24 hours to see what would happen. When I returned the next morning, it had absorbed quite a lot of the black. I did the rinsing/microwave trick and found I had exactly the result I wanted.

Now the tricky bit - to dye the whole hat. I knew this would be harder, as I don't have a dedicated dye bath, nor did I have lots of dye. Plastic bag in one of the kitchen sinks, and in went the boiling hot pre-mixed dye into the warm water. I pre soaked the hat too, in lukewarm water. In it went, and now I had to wait. I poked it around as it absorbed its first bits of dye, and tried to get the whole thing to stay under the water. This is where things went a little bit wrong. You'll find out why soon.

I left the hat to do its thing for a few hours, snipping off small swatches every so often to see how the process was going. My big dye mix was obviously stronger than the first one, as the colour was taking more rapidly. I went out for lunch, and when I returned, things were nearly done. I left it 2 more hours just for luck, and then removed the hat to see what it looked like.

A decent rinse, and then a quick microwave (why not?!) and I was less happy than with my swatch. Was it blotchy because I didn't stand and stir it for the whole seven hours? And what was that circle bit there?

Well, I had decided to weight the hat with some tins of food. The food and the tins survived (cling film) but the hat has a definite 7cm wide kidney bean tin sized circle on the underside of the brim. Hmmm. Shame too, as the hat wasn't looking too bad.

I hadn't got rid of my dye yet, so I plonked the whole thing back in. Who knows, maybe the circle will dye overnight! At least it might look a bit less obvious. And here's hoping its not patchy and blotchy. The microwave is happily still intact too.

I won't know the full results until tomorrow...until then, here's some some nerdy reading matter. Photos to follow...