Is Pyrex all right for one use?

Discussion in 'Beginners Soap Making Forum' started by alchemy_cake, Jul 5, 2017.

  1. Jul 12, 2017 #61

    toxikon

    toxikon

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    To be fair, there are a lot of "never-ending songs" around this forum... doesn't mean we should discount an interesting discussion on the effects of lye on glass. :)
     
    Last edited: Jul 13, 2017
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  2. Jul 12, 2017 #62

    dibbles

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    I agree.
     
  3. Jul 12, 2017 #63

    IrishLass

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    Right here, silly!
    Ack!- the Lambchops/Shari Lewis song! That was one of my son's favorite shows to watch when he was real little. Just when I thought I had finally gotten that song out of my head forever! Thank you ever so much for the reminder Dibbles. :twisted: :lol:


    I agree as well. Especially since there are always more and more newcomers to the craft (and to the forum) whose only prior knowledge of soapmaking may have come from reading a few blogs or watching a few videos online that unbeknownst to them contained very questionable practices or faulty info. I view threads like these as more of a positive than a negative because they help get the word out so that newcomers can get started off on the right foot.


    IrishLass :)
     
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  4. Jul 13, 2017 #64

    Traumabrew

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    I use pyrex measuring cups and/or the 6 quart glass mixing bowl from a kitchenaid stand mixer to mix oils and lye solution. Stainless steel is safe for lye solutions however aluminum isnt. Most commercial operations use stainless steel as it isnt reactive with lye. I use lab quality borosilicate beakers (the 500 ml, 1000ml and 2000 ml are quite nice and cheap) for making my lye solution. I have concerns over the lye leeching compounds form the plastic containers. I do use plastic long spout containers to portion out my soap batter and mix colors in, but the length of time they are in these containers is minimal. Lye solution will sit in its container for an extended period of time as it cools.
     
  5. Jul 13, 2017 #65

    alchemy_cake

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  6. Jul 13, 2017 #66

    shunt2011

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    And this is where my name came from..... Ha Ha!
     
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  7. Jul 17, 2017 #67

    WhiteRiverSoap

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    Pyrex is quite safe. Over time, caustic can etch the glass, but this would take literally hundreds of batches before you would even notice and you would likely throw out the pyrex cup before it caused any issues as the glass would become a bit frosted before any problems.
     
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  8. Jul 18, 2017 #68

    The Efficacious Gentleman

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    Did you read any of the previous posts before posting this?

    That aside, is Pyrex quite safe or very safe? At what sign of frosting should I stop using it? Are you assuring me completely that I will have no other issues with my Pyrex (of any quality) with my soaping? Can you provide your contact details for me to claim on your insurance when something happens to my Pyrex which doesn't fit with your guidelines for frosting etc?
     
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  9. Jul 18, 2017 #69

    navigator9

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    Back when I first started making soap, around 10 years ago, I had seen it recommended somewhere to use Pyrex for mixing lye, so I did. Soon after, definitely not "hundreds of batches" later, I noticed that the glass looked cloudy. Luckily, I read that this etching is caused by the lye, and eventually the glass will begin to release micro shards of glass. I don't know that there is any way to predict when this will happen, but it wasn't something I was willing to risk, so I threw the Pyrex out.

    pj, ever since getting rid of my Pyrex cup, I've used a SS saucepan for my lye solution. SS isn't dark, so I can easily see to the bottom, and I like that the metal makes it easy for me to gauge the temperature by feeling the outside of the pot. I've used the same saucepan for years, with no problems, and I've continued to also use it for cooking with no problems.

    I know there are plastics that can also be used for lye, but I already had the saucepan, as well as the SS stockpot that I use for making my larger batches of soap. SS is non porous, so there's no problem using SS for both soaping and cooking, provided of course, that you wash it well. I think most people have SS pots of various sizes already, so I'm surprised that more don't use them. As for DOS, I've had a batch or two early on, but not in years, and as I've said, I use the SS all the time.
     
    Last edited: Jul 18, 2017
  10. Jul 18, 2017 #70

    penelopejane

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    You are right of course about SS. I like to be able to see the batter mixing so plastic is perfect for me.
     
  11. Jul 19, 2017 #71

    penelopejane

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    You are in New Zealand. Pyrex made by Corning sold in NZ and Australia is different from that made in the USA. If it is made by Corning in Australia it will be the safer than that made in the US. The capital lettering on the container is one indication but there is also smaller writing saying where it is made. Google Pyrex for more info. It was a "good" Pyrex container that exploded on me. I still don't trust it for hot liquids.

    It would be good if you added your location to your name to avoid confusion.
     
  12. Jul 22, 2017 #72

    psfred

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    You need to be aware that "pyrex" means two different things -- it's a registered trademark for borosilicate glass by Corning, and in the old days, before the word became generic (and everything wasn't made in China) the "Pyrex" marking meant borosilicate glass. While it will eventually frost, it's OK to use a few times.

    Sadly, someone got all bent out of shape about the miniscule amount of boron that CAN (note I said CAN) leach out of borosilicate glass, and it was banned from food use. That means "Pyrex" became a trade name for glass cookware, and it's quite dangerous. Lots of reports of exploding "Pyrex" pans, etc because tempered glass is NOT borosilicate glass, it's silica based glass and quite fragile in comparison. It will indeed shatter unexpectedly under thermal stress, and does not have to be etched by lye first, although that will make failure more likely rather than less.

    So, bottom line, unless you KNOW your "Pyrex" container was made before about 1986, assume it's plain tempered glass and do NOT mix lye in it, it's subject to thermal stress cracking, a bad thing. Older Pyrex is probably quite safe -- I use it in the chemistry lab all the time for making strong lye solutions and have never had a beaker break, even a badly etched one. Lots of plain glass failures though.

    Plastic or stainless is safer, and you really don't want hot lye running all over your countertop....

    Peter
     
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