Borax purity grade

Discussion in 'B&W: Film, Paper, Chemistry' started by efreddi, Dec 6, 2007.

  1. efreddi

    efreddi Member

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    I'm running out of my stock of borax. I found the possibility to get some borax for household and/or wood preservation. Do you think that I may run in problem due to the purity grade? Any experience about it?

    Thanks


    Elia
     
  2. dancqu

    dancqu Member

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    I bought a pound from P. Formulary years ago and have
    hardly touched it. Would depend upon how you plan to
    use it. Mine is likely photo grade and would trust it
    for any use. Borax from the store I'd trust to
    make mildly alkaline a fixer. Dan
     
  3. jim appleyard

    jim appleyard Member

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    I use 20 Mule Team borax from the grocery store to make D-76; never a problem.
     
  4. gainer

    gainer Subscriber

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    IIRC, borax is pure as it comes out of the ground and is (or used to be) hauled away from Death Valley by wagons drawn by 20-mule teams.
     
  5. Kirk Keyes

    Kirk Keyes Member

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    As "pure" as anything that gets dug out of the ground. I'm not sure that your definition of "pure" as used here would meet most people's definition of pure.

    I'd recommend getting some from the Formulary or another supplier of photo-grade chemicals.
     
  6. gainer

    gainer Subscriber

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    Their's will probably come from the same grade that you buy at the supermarket. How many manufacturers of this product are there? Suppose you were a retailer like PF. How many different grades could you get if you tried? I haven't searched, but I have never have had a problem with 20 Mule Team Borax.
     
  7. Snapshot

    Snapshot Member

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    I would imagine that the 20 Mule Team borax is decahydrate in form and the photograde borax purchased from the formulary is pentahydrate.
     
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  8. gainer

    gainer Subscriber

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    AFIK the name borax is properly used only for the decahydrate. It is listed that way in the CRC Handbook of Chemistry and Physics, and was intended to be used that way in D-76. It is listed and defined that way in the 1941 edition of the War Department Technical Manual of Basic Photography. If you think you are getting the pentahydrate, and you are Adrian Monkishly obsessive, you should cut down the amount you use in order to account for the smaller amount of water of crystalization. This water has nothing to do with purity. In the usual uses of borax weight is not critical. Its solutions will have nearly the same pH over a wide range of concentrations. The capacity of a developer is more often limited by the accumulation of bromide than by depletion of borax. The tendency to single use makes the actual weight of borax even less critical. At worst, or maybe best, I believe, a change in concentration of borax will change the time constant of the reaction by which borax maintains its pH which may make a visible change in some edge effects.
     
  9. gainer

    gainer Subscriber

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    20 Mule Team Borax is claimed to be made of 100% sodium tetraborate decahydrate. No other ingredients are listed. Do not use the penta or other hydrates thinking you are getting better purity. Whenever a recipe specifies borax, it means the decahydrate. Using the same weight of any other of its hydrates will cause you to have more than the specified amount of sodium tetraborate in your solution.
     
  10. efreddi

    efreddi Member

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    Thanks to all for your answers!

    That's the point! I suspect that the photografic grade is just the name and in reality the household borax is the same stuff. But of course the price and the availability is not the same.



    Elia
     
  11. dancqu

    dancqu Member

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    Don't kid yourself. Photo Grade is one of many grades; USP
    is another. Some other this group likely can name half a
    dozen chemistry grades You can bet that there are
    at least a few grades of borax.

    Likely not so much photo grade chemistry is sold now
    as in days gone by. Likely tons/month were being
    shipped. Dan
     
  12. Kirk Keyes

    Kirk Keyes Member

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    This is very likely a false assumption.

    And how many manufacturers - good question. From RIo Tinto's web page, www.borax.com - "Rio Tinto Borax operates California’s largest open pit mine in Boron, California - one of the richest borate deposits on the planet. The company supplies nearly half the world’s demand for refined borates, minerals essential to life and modern living."

    Go look at that page. See how many applications they are producing borax for. Do you think they are making these grades just for the heck of it? Do you really think that each and every grade is using borax that has simply been dug out of the ground with no additional refining? They most certainly are not.

    Have you been to a borax plant and seen how they mine the stuff? I have - It's next to the town of Boron, CA. It's next to Edwards Air Force Base in the Mojave Desert. The borax at Boron, CA is from an open pit mine. They dissolve the mineral with hot water and then it goes into large, open pools to let the water evaporate and they are subject to any dirt the weather happens to bring along. Check out the satellite shot of it from google http://maps.google.com/maps?f=q&hl=en&geocode=&time=&date=&ttype=&q=boron,+CA&ie=UTF8&ll=35.044052,-117.718506&spn=0.105687,0.158272&t=h&z=13&om=1 You can see how they are evaporating the ore and then they collect it in heavy machinery. Not a very clean process.

    It's just like using the right tool for the right job. Sure a flat bladed screw driver can drive screws, but when you need to drive a Philip head, or a Torx head or any of the other kinds of screws, you really will get the best performance with the right tool. Same thing applies to chemical grades.
     
  13. Photo Engineer

    Photo Engineer Subscriber

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    I've said it before and I'll say it again: Everyone wants to produce quality photos from economy priced chemicals and films and papers. Everyone wants quality from teaspoon measures and eyedropper measures rather than grams and milliliters.

    If you want quality, you pay for it or you get dirt, dust, or that 5% impurity of 'whatever' when you read the label and it says 95% pure.

    If you buy economy products of any sort, then why use an expensive timer, just count one one thousand, two one thousand, three onethousand and etc. to time the development, fixing and washing. Guesstimate times for exposure too.

    PE
     
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  15. gainer

    gainer Subscriber

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    Suppose you are right and the 20 Mule Team Borax is not what they claim, 100% sodium tetraborate decahydrate. When you buy it from Photographers' Formulary do you get any assurance that their's is in fact 100%? Does anyone in APUG have evidence that using 20 Mule Team borax has caused a problem in any of the many recipes that call for borax? Do you know the tolerance for error in any of these recipes? Can you supply evidence, personal or published, that ordinary grocery store borax is not good enough? As for teaspoon measures, have you tested those for consistency of weight or effect on photographic solutions? I have, long ago, and reported my results in an article for Petersen's Photographic (April, 1973) called "Kitchen Tested Soups". Kodak's instructions for those who want to mix their developers from scratch is to have a scale or balance good to 0.1 grams.

    Researchers like PE need to know such things as tolerances, deviations from experimentally determined optima that will not cause noticable difference in performance, if their discoveries are to be put to practical use. You know for fact that as soon as one opens a package of dry ingredients to mix a developer, the ingredients are likely to be changed, and who knows what changes will occur when local water is used to mix them. What specifications would Kodak put on an order for borax, or sodium sulfite, or hydroquinone, or Metol for packaging the components of D-76?

    I have a cheap timer from Radio Shack and a metronome. The timer does very well, thank you, for measuring time of development to the second if needed, and the metronome is quite good for timing exposures under the enlarger.
     
  16. Jim Noel

    Jim Noel Member

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    I'm with Gainer. There is a lot more room for error, or leeway, or whatever one wishes to call it, when mixing photographic chemistry than some would have us believe. I still have a copy of his article from 1973 and pass it along to current students. Too many times in my life I have headed for the kitchen when missing an ingredient then have everything turn out correctly to worry so much about purity. Sure, there are exceptions, but I believe they are the exception.
    Jim
     
  17. Snapshot

    Snapshot Member

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    Based on my personal experiences, a small deviation in chemistry measurement generally has little impact on the output of my pictures. The greatest source of deviations for me is temperature control and once I've refined that art, my pictures markedly improved in quality and consistency.
     
  18. DarkroomExperimente

    DarkroomExperimente Member

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    OK....let's have everybody pitch in $5 and we'll send a box of 20 Mule Team Borax off to a lab for testing & find out precisely what's in there besides the borax

    I throw my film into all kinds of homemade concoctions ( Tri-X screams like a lobster in the bubbling brew ), but I wouldn't dare put somebody's wedding photo's in my cauldron


    gotta run, need to get more eye-of-newt
     
  19. BradS

    BradS Subscriber

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    Patrick's post is so good, it bears repeating.
    There does not appear to be any evidence what so ever to support the hypothesis that 20 Mule team Borax from the grocery store is insufficiently pure for use in B&W developers.

    Further, regarding "Photo Grade" chemicals...I suggest you find a real definition of what that excatly means. It does not mean "pure" by any stretch of the imagination, in fact, photo grade can have all kinds of impurities - just not significant levels of impurities that would have a detrimental effect in the intended photographic applications.
     
  20. Mick Fagan

    Mick Fagan Subscriber

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    I have noticed a difference with Borax.

    Many years ago I was trying to put together a solution, the only Borax I could get my hands on was some from a hardware store, fine I thought. Well not quite!

    I was mixing a film developer, cannot remember what but if say it was D76, I would only have used 2gms for 1 litre.

    What I found was that what I dropped in, didn't all go into solution. Eventually I figured it must have been impurities, so I finished the solution, cooled it, then filtered out the solids.

    As far as I know the solution developed the film alright, otherwise I would have made a some warning notes for myself.

    Currently, I use Analytical reagent grade Sodium Tetraborate, with a purity of 99.101%, for my film developing solutions.

    I wouldn't really know how much difference, cost wise, this purity is, as I am on the last of two large bottles I bought in the late sixties.

    Mick.
     
  21. gainer

    gainer Subscriber

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    When borax is specified for use in developers by knowledgable persons it is the decahydrate. Fortunately, in most developers it is used as a buffer, and its buffer pH is phenomenally independent of concentration. Otherwise, in using the analytical reagent grade sodium tetraborate you are not necessarilly doing yourself a favor. The molecular weight of the tetraborate is 201.22 and that of its decahydrate is 381.37. If you weigh 2 grams of the anhydrous tetraborate you are getting the equivalent of 3.8 grams of borax.

    I have never in 50 years or so never seen any undissolved sediment in a borax solution that could not be attributed to exceeding the solubility of borax. In other words, if I added more water or increased the temperature, the sediment would dissolve. I have always used 20 Mule Team Borax.

    You can if you wish continue to use the analytical grade, but check to make sure it is the decahydrate or reduce the amount accordingly.
     
  22. Mick Fagan

    Mick Fagan Subscriber

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    Gainer, Interesting thing about the impurities I encountered, was that it was supposed to be 100% Borax. That is really was what I was trying to convey.

    I do take your point, about the different molecular weight of the reagent grade.

    The label on my current jar, tells me that it's weight is 381.43.

    Mick.
     
  23. gainer

    gainer Subscriber

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    So it must be the decahydrate, as it should be if it says "Borax". Labels are strange things. Then, too, impurities can get into a product several places along the line. IMHO, borax is the thing we should worry about the least, as in most recipies + or - 10% won't make a noticable difference. The concentration of the sodium borate will affect the local rate of change of pH more than the equilibrium value. Old timers used to increase borax in D-76 to as much as 20 grams/l to boost the film speed.
     
  24. Kirk Keyes

    Kirk Keyes Member

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    Like ones that tell you something is 100%. Don't believe them. They are not looking hard enough to find the impurities.

    Mick's AR grade is certainly more believable - to get to AR grade it was most certainly purified more that Borax that was hauled by a 20 mule team, and even that extra purity could not get it to 100%.

    So, Pat, why are we supposed to beleive that your inexpensive grade of borax is actually 100%?
     
  25. Kirk Keyes

    Kirk Keyes Member

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    If we are only worried about pH, then you are right. If we are worried about buffer capacity, then you are less right. If we are worried about impurities that may affect our results or scratch our negs, then you are way less right.
     
  26. gainer

    gainer Subscriber

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    I never said you had to believe anything. I did not assume anything. The statement that something is probably this or that is not an assumption of fact, and I did not even estimate the probable eror of my statement. I did not even say I believed what the label said. I only reported it. My assertion that in most cases for which we use borax, accuracy is not critical is, I think, true or I would not have said it. If you have some evidence of harmful impurities in 20 Mule Team Borax, please tell us what they are. All I can say is I have used it photographically for over 60 years with no troubles. Anything that is good enough to deodorize baby diapers is good enough for my needs.

    If you are so concerned about the content of the 20 Mule Team Borax box, you could do us a great service by analyzing it to see if it comes up to the 99+ % of the analytical reagent, and what in fact makes up the difference, and also what makes up the difference between the analytical reagent and absolute purity.

    I am a great believer in the word ASS-U-ME. I learned it in my 30 years as an Aeronautical Research Engineer-Scientist.