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  1. #1
    RobertP's Avatar
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    Is there a Chemist in the house?

    I just received a 1 liter bottle of formaldehyde 37%. There is a sediment that is settled in the bottom. Is this normal? Should I just use the clear liquid that is on top or should I shake and mix the sediment into the solution? Apparently the sediment is not going completely into solution. Does this mean that the solution is already to saturated and won't allow all the particles to dissolve? I'm using this as a hardner for Gum. Any help would be appreciated

  2. #2
    John_Brewer's Avatar
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    No, you shouldn't have anything at the bottom. Formaldehyde is actually a gas at 20 deg C, you have 37% formaldehyde solution, sometimes called Formalin (a trade name). The fumes are dangerous as well as unpleasant so don't try and filter it, certainly not outside of lab conditions. I'm guessing from you posting in the alt process forum you're using it to harden gelatine sizing. I would pipette off what you need as and when just leaving the sediment.
    ~John~
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    www.johnbrewerphotography.com
    There are 10 types of people in this world - those who understand binary and those who don't.

  3. #3

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    Robert,

    Go to the nearest tool rental place (United Rentals, or whatever you have near you) and get a good half face respirator and also the cartridges that are suitable for formaldyhide if you don't have one already. The cartridges are good for about 3 hours. I write on the cartridge the total time I have it on so I know when to replace.

    As John says, formaldehyde is a gas, so the sediment is not what you want, and it is probably nothing to worry about as long as there isn't too much of it. Pour off the top or pipette from the top and you'll be fine. I poured a bit into a bottle with a dropper and use it that way.

    One time using that stuff with a mask will convince you to get one...

    ---Michael
    www.mutmansky.com
    B&W photography in Silver, Palladium, and gum bichromate.

  4. #4
    RobertP's Avatar
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    Quote Originally Posted by John_Brewer View Post
    No, you shouldn't have anything at the bottom. Formaldehyde is actually a gas at 20 deg C, you have 37% formaldehyde solution, sometimes called Formalin (a trade name). The fumes are dangerous as well as unpleasant so don't try and filter it, certainly not outside of lab conditions. I'm guessing from you posting in the alt process forum you're using it to harden gelatine sizing. I would pipette off what you need as and when just leaving the sediment.
    John, Yes very unpleasant indeed. I'm using a respiratory and I'm gloved when handling it. The darkroom is very well ventilated with a good filtered fresh air supply. So I'm pretty comfortable working with it. You are also correct as to hardening the sizing. My question is.. what is the sediment? If it not suppose to be there then should I even consider using it? Thanks
    Last edited by RobertP; 10-06-2006 at 12:00 AM. Click to view previous post history.

  5. #5
    RobertP's Avatar
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    Quote Originally Posted by Michael Mutmansky View Post
    Robert,

    Go to the nearest tool rental place (United Rentals, or whatever you have near you) and get a good half face respirator and also the cartridges that are suitable for formaldyhide if you don't have one already. The cartridges are good for about 3 hours. I write on the cartridge the total time I have it on so I know when to replace.

    As John says, formaldehyde is a gas, so the sediment is not what you want, and it is probably nothing to worry about as long as there isn't too much of it. Pour off the top or pipette from the top and you'll be fine. I poured a bit into a bottle with a dropper and use it that way.

    One time using that stuff with a mask will convince you to get one...

    ---Michael
    Michael, I'm using a double cannister half face respirator. But I didn't realize that there are special cartridges for formaldehyde and that they last only 3 hours.The cartridges that are in mine are: R51A chemical cartridge for organic vapors. The paper work that came with the cartridges is long gone so I'm not sure if they are rated for formaldehyde gas so I'll replace them. Thanks, Robert
    Last edited by RobertP; 10-06-2006 at 12:19 AM. Click to view previous post history.

  6. #6
    vanspaendonck's Avatar
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    [QUOTE=Michael Mutmansky;373567]Robert,

    Go to the nearest tool rental place (United Rentals, or whatever you have near you) and get a good half face respirator and also the cartridges that are suitable for formaldyhide if you don't have one already. The cartridges are good for about 3 hours. I write on the cartridge the total time I have it on so I know when to replace.

    I wonder whether a half face respiator provides adequate protection.
    A few years ago I met a Dutch Leica collector who used to work in a hospital, where he suffered overexposure to formaldehyde gas. This caused such damage to his eyes that he has become an invalid. I would be extremely careful with this stuff.

  7. #7
    RobertP's Avatar
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    I think the proper cartridge is the R60A cartridge for formaldehyde. I'll replace the R51A. I'm all for good lab practices.

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    RobertP's Avatar
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    vanspaendonck, I imagine some of those old timers working with embalming fluid, worked in it up to their elbows without proper protection. I'll be careful and get the right cartridges for the respirator. Plus I'll stop using it when I need glasses. Thanks for the heads up. Robert

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    After a period of time the formaldehyde in solution polymerizes to a substance known as paraformaldehyde which is insoluble in water. This is the sediment that you have noticed.

    When I was in high school most everyone had to take biology and dissect a dead frog. The classroom reeked of formaldehyde, bo one died. Unfortunately, today, everyone is afraid of chemicals (stage director, please insert creepy music here). Nothing is kept in perspective.

    The last MSDS that I read said that formaldehyde was a possible carcinogen. While it is irritating in higher concentrations, it should be safe for occassional use for photographic purposes such as hardening baths.

    I wonder if the EPA ever did a followup study on morticians to see if there was any increase in cancer with members of that profession.

  10. #10
    RobertP's Avatar
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    Quote Originally Posted by Gerald Koch View Post
    After a period of time the formaldehyde in solution polymerizes to a substance known as paraformaldehyde which is insoluble in water. This is the sediment that you have noticed.

    When I was in high school most everyone had to take biology and dissect a dead frog. The classroom reeked of formaldehyde, bo one died. Unfortunately, today, everyone is afraid of chemicals (stage director, please insert creepy music here). Nothing is kept in perspective.

    The last MSDS that I read said that formaldehyde was a possible carcinogen. While it is irritating in higher concentrations, it should be safe for occassional use for photographic purposes such as hardening baths.

    I wonder if the EPA ever did a followup study on morticians to see if there was any increase in cancer with members of that profession.
    Gerald, I just spoke with a scientist at Fisher Scientific and he said the exact same thing, that formaldehyde polymerizes to a substance known as paraformaldehyde which will never go back into solution. He said that this is usually accelerated by improper storage. A warehouse where the temp has dropped below 20C (I think that was the temp he cited) will cause this almost immediately. I asked what he would recommend and he said "dump it, it is no longer a 37% solution because of the polymerization" I called Science Lab Chemicals and Laboratory Equipment Co. in Houston, Texas and they refuse to make good on the purchase. They also didn't ship it Hazmat like they should. And some of the formaldehyde leaked around a cap that wasn't properly sealed.(no inner seal inside the cap). It is scary to think these people are handling these types of chemicals so unprofessionally. I guess I'm out the price of a liter of formaldehyde. But just a warning to others not to buy from these people. Fortunately here in the small town where I live the local pharmacist said he will order the formaldehyde for me.

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