pixdyer pixdyer
I'd gotten the idea that it would be possible to revive a synthetic indigo vat by mixing in a bit more thiox and/or soda ash.  However, so far I've failed to make this work.  There's a fair amount of blue in the vat liquid which makes me think that if I just get the right chem balance it should be possible to dye more fabric.

Anyone made this work?  And if so, how?

Thanks.
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Jacquardmod Jacquardmod
How long was the vat "dead".  I have done this, but it is when the vat first starts declining.  

Really the pH should still be high, I think the addition of Soda ash might be redundant.  I can't imagine it will hurt though.  How much reducer are you adding?  50 grams is what we put in the kit.  
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Mossmilldesign
I have tried to do this but failed. I thought it had more to do with not maintaining the temperature of the vat but I don't have enough experience with indigo to know for sure. I started using an indigo fiber reactive dye because as much as I love indigo, keeping the vat viable was beyond my current knowledge base or skill set. Even though it's nearly impossible to tell the difference between reduced indigo and the fiber reactive dye color-the process of developing the indigo color is so compelling.
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pixdyer pixdyer
I suspect it might be the temperature. I got some testing strips delivered today and checked the solution: it's got a pH of about 10 to 11 (those colors are hard to judge). I already added some more thiox (about a teaspoon or so for a 4 gallon vat), so I should be fine on the re-reduction side. Vat's in my basement right now and it's pretty cold down there, so I'm thinking of sticking the vat in a sink full of hot water to try to get it warm enough to dye. The vat's only a week or two old, but I did a lot of bulk dyeing with it, AND I'm kinda sloppy with drips,etc, so it's probably kind of oxygenated. We'll see. I agree with you Mossmill... the best part of the indigo process is the dipping/dyeing process and the resultant control it offers. I just wish I didn't have t keeping buying the danged kits.
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Jacquardmod Jacquardmod
The vats they keep going for long periods of time do have heat under them.  It could very well be the heat.  I used super hot water in the bath the last time i made it and it lasted longer than ever before, so yes temp is involved.  My vat lasted at basically full strength for 8 days in this instance.  
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Mossmilldesign
I would use an immersion heater. It's what they suggest in order to keep a vat viable- by maintaining the temperature. I'll probably get a pre reduced kit in January when I have more time and will definitely get one. The last vat I did, I waited til summer when it was hot and I was able to keep it going for almost a month- I just put the lid on and put it outside where it was really hot after I had dipped whatever pieces I had ready. I did add thiox at some point- and I dyed a lot of yardage with that vat- definitely got my moneys worth but the indigo was spent and I wasn't getting anything but a very light blue at the end. 
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Mossmilldesign
I consulted with someone more knowledgable than I am about maintaining the temperature. She said maintaining heat wasn't neccessary with prereduced indigo and that you could ladle some out and reheat it and carefully pour it back into the vat and check the temperature. She said the pre reduced works best at 78°. If it gets colder than that, you won't get the same results. She said an immersion heater was unneccessary for pre-reduced indigo.
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Jacquardmod Jacquardmod
Yeah that is true.  It doesn't have to stay hot the whole time, but is good to heat when trying to reduce it again with more thiox or sodium hydrosulfite.  

It is also easier to add the reducing agents before it is totally exhausted than trying to bring it back from nothing.  
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