Sunday, 19 September 2010

testing the water

We were back in the UK again last weekend working so I decided to let the water try and clear itself (some hope!) The obvious thing to start doing is testing the water we have available. We already know that we have hard water so have jug carbon filters in the house, for our drinking water, there's one option to try, we collect rain water in butts, there's another and then we can spend lots of money buying de mineralised from the supermarket. I have always used the demineralised for extracting the colour, but there are too many parts to the dyeing process to buy it all, we need a viable solution!

Although I think there may come a time where I have to have the water analysed properly, over the last couple of days I've done the following tests.
I had a 100g hank of merino lace that I mordanted before I left North Wales (lovely soft water), so I split it down into small hanks of the same size and soaked them out in de mineralised water. (We had an analysis of the water from Dwr Cymru quite a while ago so that was the most neutral I could think of in a hurry!) I put 10g ground cochineal into 500ml demineralised water and left it to soak overnight. Next day I heated to boiling and simmered for half an hour then left it to cool. There was some evaporation so I split off 4 x 50ml liquid into separate tubs.

Into a stainless steel pan I put the first 50ml and added 1/2 pt demineralised water, added 1 small hank wool and heated to boiling, held there for 5 mins then allowed to cool enough to handle. Removed hank and poured the liquid back into its tub. The pan and jug were washed out with demineralised water between each sample and the same method was used for each type of water. I tried filtered tap water, tap water and rain water that I passed through a filter paper to remove any solid particles.(this picture is the tap water sample)


Demineralised water stayed a beautiful clear red all through the experiment as did the rain water.

The tap water and carbon filtered tap water immediately went "gloupy" as soon as they were added to the cochineal liquid in the pan - you can see the "sludge" in the tub at the bottom.

filtered water went gloupy in the same way as tap water

Rain water was clear and red, although slightly brighter than the distilled, I would say that the colour shows that the water is slightly acidic (I tested with litmus afterwards)

Looking at the samples you can see that the tap water and filtered water are "patchy" with dull bits and OK bits, this would imply that there is some iron contamination there, the rainwater and de mineralised water are both good clear reds. It;s not very obvious but the rain water is slightly brighter - more scarlet (think that's my lack of photography knowledge!)

Clearly a carbon filter is not going to be solution enough! I need to find out what has been added to the water and then see if there is a filter that can clear it, what I really want to do (and have for quite a while) is rainwater harvesting for which we will need to get HUGE storage tanks to be able to store enough!

I mordanted 3kg of the merino whilst the water was really bad, so now I need to know whether I've ruined it or it can be salvedged with other dyes. The next tests are going to be with weld and the mordanted yarn to see if I get my normal yellows, and I'd better do some lightfastness testing too, to see how that's affected.

I know I want to spend more time in the dyehouse - but I didn't think it would be like this!


Knitsister said...

Golly!!! That's quite a chemistry lesson, I think you should get a degree from Cambridge for all this hard work. Shame we can't get a pipe laid from N.Wales to you over there so you could continue to have lovely soft water from here.
Hope all is well with you guys, did you get my mail the other week?
Hugs from Heike x

Helen said...

Have you tried boiling the water and allowing the sediment to settle then pour off the clear? This is what Michelle Wipplinger said to do if you had hard water.
Otherwise -gosh what a bummer but I have every faith you will solve it.
Nice the rainwater gives such a good colour.

Debbie said...

Well, I think there's nothing else for it, you'll have to come back to the UK ; )

My MIL used to take bottles of our tapwater back to Bristol for her ironing as their water was so hard. Maybe you could pop over with some big containers and take some lovely Welsh water back to France with you!

Karen said...

I can so relate to this post. I have not tried experiments like this but have some elements the same in Belgium.
Cochineal bugs ground up seem to consistent colour - extract not so much. Shows up when overdyed with say Weld or Madder.
Onion skins no mordant the skin colour ; Alum + CoT mordant once yellow, second time rich bronze. Same bag of skins.
I too have been looking at using distilled water.
I look forward to further experiments and comments.
I understand that Andie in South France had significant changes in colours too.

Dorothy said...

I'm interested in this - we have iron in our tap water, there's a visible effect on greening effect with Weld - I don't get pure yellow - I haven't tried cochineal yet.