I'm trying to make an alkaline fixer from sratch but I'm not able to find sodium metaborate, is there a substitution?

Thanks

-- Xosni (xosni@gega.net), August 23, 2001

Answers

half the amount of Sodium carbonate will do.

-- Jorge Gasteazoro (jorgegm@worldnet.att.net), August 23, 2001.

Somebody told me that Borax & sodium metaborate ar einterchangeble. Is it true?

-- Xosni (Xosni@gega.net), August 24, 2001.

No, they are not interchangable.

-- Ted Kaufman (writercrmp@aol.com), August 24, 2001.

First of all, in fixer formulae, you need to choose acids and bases carefully. If you look at traditional hardnening fixers, you see things like boric acid in addition to glacial acetic acid. Those are the result of seeking thiosulfate compatibility as well as hardner compatibility, besides other things. In non-hardening formulae, selection is easier but still a number of things must be considered besides pH.

If you just want the benefit claimed for TF-{3,4}, try Ilford Multigrade Fixer (not Universal Fixer) and see if you like the result. As you might get some idea from one of my earlier postings here, in my understanding, you get nearly all the benefit of what's claimed for TF-4 by adjusting the pH to be anywhere between 6 and 7. Ilford Multigrade Fixer is at about 6. (Freshly mixed unused solution may be somewhat lower, but it's still ok.) Sodium metaborate would set the pH higher than this range, and you will smell ammonia.

If you want to try the published formula, but not so willing to go through your thinking process, then stick with sodium metaborate. I do not recommend a quick substitution, even if they are said to work in most general developer formulae.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), August 24, 2001.

Isn't Kodalk available anymore? Kodalk is Sodium Metaborate, by all accounts. A quick websearch just showed that a company called Bostick & Sullivan have Sodium Metaborate for sale.
Lastly. Alkali Fixers - why?

-- Pete Andrews (p.l.andrews@bham.ac.uk), August 28, 2001.

Hi Pete, alkaline fixers have a couple of uses. Especially popular with pyro users because acid fixes apparently are not conducive to the stain. Have also heard arguments for keeping paper processing alkaline to enable going striaght from fix to Selenium toner (see www.heylloyd.com and technical section for an interesting paper on same). Cheers, DJ.

-- N Dhananjay (ndhanu@umich.edu), August 29, 2001.

Pete, Kodalk is not Sodium metaborate, it is if my memorie serves me right sodium pentaborate decahydrate. As I stated before 1/2 as much of Sodium Carbonate will work IF it is diluted in an alkaline solution. Of course if you dilute it in an acid solution then you get foaming and CO2. Mostly this is used in the little chemistry games like the volacano etc.

-- Jorge Gasteazoro (jorgegm@worldnet.att.net), August 29, 2001.