DIY light source for 10X10" enlarger.

Discussion in 'Darkroom Developing and Printing' started by jjs, Apr 9, 2008.

  1. Plenty.

    But, if you are only drawing 100 watts then you don't need a
    contactor. A contactor is only needed for 300 watts or more.
     
    Nicholas O. Lindan, Apr 11, 2008
    #41
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  2. If it is a 220V enlarger where else do you suggest he plug
    it in?

    It is common for large enlargers, Durst L1840 for instance,
    to run on 220V.
     
    Nicholas O. Lindan, Apr 11, 2008
    #42
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  3. Huh????

    Don't bother explaining, I really don't want to know.
     
    Nicholas O. Lindan, Apr 11, 2008
    #43
  4. jjs

    ____ Guest

    yes but he us trying to build the lamp house from scratch and you seem
    to advocate messing around with lethal current.

    Maybe you missed that Mr. Engineer.
     
    ____, Apr 11, 2008
    #44
  5. Well, Mr. Layman, 120 volts can be just as lethal as 220. Besides, JJS
    has professed his extreme aversion to anything involving "juice", so you
    can stop worrying.

    Besides, apropos another little sub-thread here, the last time I got
    zapped, it was with 277 volts (that weird lighting voltage Nick Lindan
    mentioned). I survived it. So, Nicholas, why do they use that strange
    voltage? (This was in a large commercial building.)
     
    David Nebenzahl, Apr 11, 2008
    #45
  6. jjs

    Ken Hart Guest

    Actually, there was no mention of current, only voltage. It is possible to
    kill with as low as 20-30 volts, it's also possible to handle several
    thousand volts without fatal results. It's current that fries, voltage just
    knocks your keister across the room.

    I've gotten nailed by 20,000 volts from a TV picture tube with no ill
    effects (could someone please answer the phone!), and gotten badly burned by
    30 volts from a broadcast antenna.
     
    Ken Hart, Apr 11, 2008
    #46
  7. 1) Voltage isn't current.
    2) Most of the world uses 220V for residential power, America
    is in the minority in it's use of 120V.
    3) 120V poses just as much danger as 220V.
    4) At 1KW and above 220V is the proper voltage to use.
     
    Nicholas O. Lindan, Apr 11, 2008
    #47
  8. jjs

    jjs Guest

    True, and if necessary for proper operation, we will use 220V. It's right
    there in the shop and the darkrooms. Might as well do it right.
     
    jjs, Apr 11, 2008
    #48
  9. jjs

    jjs Guest

    you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
    It better not contain oil. I use it all the time to wipe plastic before
    priming it for paint. Ain't no oil in it.
     
    jjs, Apr 11, 2008
    #49
  10. It depends -- there are two types of 70% 'rubbing alcohol': isopropanol and
    denatured ethanol. The denatured ethanol is for medical use and labeled
    USP.

    Then there are 9x% isopropanol and various witch hazel libations.

    I have, on occasion, picked up the wrong stuff. The USP version has a
    distinct Doctor's office odeur and sometimes a light pink tint.
     
    Nicholas O. Lindan, Apr 12, 2008
    #50
  11. If you do adapt the design and use "hot" blubs, you'll need a sheet of
    heat absorbing glass. Place it on top of the diffuser, which I recommend
    be double flash opal glass--coated both sides--and not plastic like is
    used with cold light heads. Opal glass diffusers better and isn't prone
    to heat warping. That's the way did set mine up 20+ years ago. With
    good strong air flow through the head, never had any heat problems at the
    negative.

    Stef
     
    Stefan Patric, Apr 12, 2008
    #51
  12. If it says isopropyl alcohol or pure isopropyl alcohol on the bottle,
    then you're okay. Most of the time, there is a percentage like 70% or
    90%, etc. That's the percentage of alcohol to water. I can usually find
    upwards of 97% pure in a just regular drugstore. However, if it says
    RUBBING alcohol, that has oil in it as a lubricant for massages; hence,
    the, name rubbing. There's not much, but it's there.

    Stef
     
    Stefan Patric, Apr 12, 2008
    #52
  13. jjs

    John Guest

    Thanks for the earlier tip regarding A. Adams' mention of a light source for
    LF enlargers. It is in his book _The Print_. Will read it tonight.
     
    John, Apr 12, 2008
    #53
  14. jjs

    ____ Guest

    I know, I jumped the gun.
     
    ____, Apr 12, 2008
    #54
  15. jjs

    David Kazdan Guest

    Nicholas:

    Are you sure on the medical ethanol?

    USP means United States Pharmacopeia, taken to mean "of highest purity"
    (after "reagent" and "analytic" grades of chemicals). The only ethanol
    USP I have ever come across is 100% ethanol, prepared from a benzene
    ternary azeotrope made after alcohol distillation to a binary azeotrope
    (95% ethanol in water), then with the last trace of water removed with
    magnesium. It's not denatured, and at least used to carry a federal tax
    stamp as potable alcohol (although very expensive for the concentration
    of alcohol, much cheaper to buy vodka and drink twice the volume).

    Denatured alcohol isn't generally used for medical purposes because the
    most common denaturants (most common is methanol) are toxic, and many
    are skin-absorbed.

    David

    David Kazdan, MD, PhD
    Cleveland, Ohio
     
    David Kazdan, Apr 12, 2008
    #55
  16. jjs

    ____ Guest


    http://www.jtbaker.com/msds/englishhtml/E2012.htm


    "ETHYL ALCOHOL COMPLETELY DENATURED

    1. Product Identification
    Synonyms: Alcohol; spirits of wine; potato alcohol; CDA Formula 19
    CAS No.: Not applicable to mixtures.
    Molecular Weight: Not applicable to mixtures.
    Chemical Formula: Not applicable to mixtures.
    Product Codes: 3791, 7018

    2. Composition/Information on Ingredients

    Ingredient CAS No Percent
    Hazardous
    --------------------------------------- ------------ ------------
    ---------

    Ethyl Alcohol 64-17-5 95%
    Yes
    Methyl Isobutyl Ketone 108-10-1 4%
    Yes
    Kerosene 8008-20-6 < 1%
    Yes "
     
    ____, Apr 13, 2008
    #56
  17. The key words seem to be 'rubbing' and 'USP'...

    o "Rubbing alcohol" w/o USP is 70% isopropanol

    o "70% isopropanol USP" is not, TTBOMK, labeled 'rubbing'

    o "Rubbing alcohol USP" is 70% ethanol w/ acetone and bittering

    o "Alcohol USP" is ethanol

    I think the logic is that acetone is less poisonous than
    isopropanol and paying ATF tax on ethanol for use as rubbing
    alcohol is bad for the bottom line not to mention it's
    effect on the level of sin in both the massage parlour
    business and the hospital's PM&R department.

    Advice worth price charged and if challenged I
    will disavow all knowledge ...
     
    Nicholas O. Lindan, Apr 13, 2008
    #57
  18. jjs

    John Guest

    FWIW - 70% isopropyl is preferred over 100% alcohol for disinfectanting it
    penetrates the membrane of tubercle bacillus to disable it while 100% does
    not. At least forty years ago it was so believed. That's the last time I
    checked. :)

    OB darkroom - What part did alcohol have in the film developer Ethanol Blue?
     
    John, Apr 13, 2008
    #58
  19. jjs

    David Kazdan Guest

    Serves me right for not checking a bottle in the medicine cabinet--I
    thought that chemicals labeled USP were "pure." At any rate, ethyl
    alcohol USP is not denatured, is it?

    David
     
    David Kazdan, Apr 13, 2008
    #59
  20. jjs

    jch Guest

    _____
    Would one of the Fulham (http://www.fulham.com/) line of electronic
    Workhorse ballasts be suitable for powering lamps for a cold light head?

    I use them for regular fluorescent tubes (4 ft and 8 ft) in house and
    workshop.
     
    jch, Apr 14, 2008
    #60
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