Glass and lye; truth or myth?

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Invest in a Laser Infrared thermometer. You can get them for around $18-24 dollars on Amazon, Ebay, Walmart, etc. The only thing I would do extra is put a fresh good top brand battery in it, such a Duracell, Eveready, or Rayovac. The Chi-nee supplied batteries are sketchy at best.

These are much more accurate and safer to use because the thermometer doesn't touch the product at all. They're used extensively in the restaurant industry for checking holding temperatures of food on the line. You can choose between Fahrenheit or Celsius readings, they have a backlight option too. Pistol grip is comfortable for any size hand.

View attachment 61306
Thank you for the recommendation! I ended up buying this exact model and today soaping with it seems a different thing, it's very convenient to use. I just need to remember to stir well so that I'm not just taking the surface temperature.
 
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Thank you for this thread.

Has opened my eyes to safety issues.
I use plastic jugs for mixing lye solution.

Melt hard oils - larger amounts in stainless steel pot on stove, and use same pot for mixing soap.

For the smaller quantities though, I'm guilty of melting hard oils in pyrex jugs/bowls in microwave and making soap in same.

So now been looking for microwave suitable plastic containers to melt oils & mix the soap batter.

Can any of you kind souls offer some suggestions as to what you use?

I don't want to use too many containers.

Thank you so much.
 

Johnez

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Thank you for this thread.

Has opened my eyes to safety issues.
I use plastic jugs for mixing lye solution.

Melt hard oils - larger amounts in stainless steel pot on stove, and use same pot for mixing soap.

For the smaller quantities though, I'm guilty of melting hard oils in pyrex jugs/bowls in microwave and making soap in same.

So now been looking for microwave suitable plastic containers to melt oils & mix the soap batter.

Can any of you kind souls offer some suggestions as to what you use?

I don't want to use too many containers.

Thank you so much.

PP#5 plastic is considered lye safe. It's the number I look for when buying pitchers, measuring cups, or containers. Very easy to find.

Edit- Earlene and Irish Lass just helped me with this:

Just make sure the container is made of Polypropylene (recycle code #5 - US) or HDPE - High Density polyethylene (recycle code #2 - US). Either is good for masterbatch lye solution storage.

Personally, I prefer the very sturdy Essential Depot lye bottles that have child-proof caps for my mb lye solution. One perk is that they are already labled as caustic and NaOh, as well as other safety precautions, but that's only part of why I like them. The size is best for my hands, as they don't hold too much liquid for me to lift and pour.

I premix my lye all the time in a 50/50 solution using distilled water, and so far, I have not had any trouble soaping with it, even
as an experiment I waited over a year to use it. Maybe it was the 'luck of the Irish', but nothing out of the ordinary happened when I soaped with it.

I store mine in a repurposed, well cleaned/rinsed liquid laundry detergent bottle with a no-drip spout, made of HDPE #2 plastic, and I mix my solution beforehand in a large Rubbermaid pitcher made of PP #5 plastic. Just a heads-up: it sure seems to take nearly a gazillion rinses to clean all the residual laundry soap out of the detergent bottle beforehand, so fair warning. My lye solution doesn't go in unless there's not even a single little soapy detergent bubble left. lol

View attachment 61849


IrishLass
 
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earlene

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So now been looking for microwave suitable plastic containers to melt oils & mix the soap batter.

Can any of you kind souls offer some suggestions as to what you use?

I don't want to use too many containers.
For melting oils in plastic vessels in the microwave oven, I use the same vessels I mix soap in (PP or HDPE plastics). Both work just fine for both purposes (melting the oils in the microwave AND mixing lye soap batter.)

Although, sure, Pyrex can be used to melt in the microwave, I don't like it for that purpose because:
#1 it's breakable and I have had too many glass-breaking accidents in my kitchen,
#2 it gets too hot to handle, but most importantly
#3 my microwave oven is slightly above head-height in my kitchen, so I don't like lifting heavy breakable items full of hot liquid down from that height.

Not to mention I'm getting old and weight matters when old hands get weaker and don't grip as well as when I was young & invincible!
 

dibbles

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Thank you for this thread.

Has opened my eyes to safety issues.
I use plastic jugs for mixing lye solution.

Melt hard oils - larger amounts in stainless steel pot on stove, and use same pot for mixing soap.

For the smaller quantities though, I'm guilty of melting hard oils in pyrex jugs/bowls in microwave and making soap in same.

So now been looking for microwave suitable plastic containers to melt oils & mix the soap batter.

Can any of you kind souls offer some suggestions as to what you use?

I don't want to use too many containers.

Thank you so much.
I had to replace my mixing bowl a couple of years ago and ended up with this one. It is sturdy and I like that there are measurements printed on the inside of the bowl that are easy to read.
For larger batches I have something like this, which I also like. I do like the pour spout on this one better than the one on the batter bowl above.
On the rare occasion I make a batch larger than this will hold, I use a repurposed 1 gallon pail.
For smaller batches, I use a 4 cup measuring cup that you can find just about anywhere. I tried one of the Dollar Store mixing bowls, but the handle wasn't sturdy enough for me and I use it for other things. A lot of people use those and like them, so it isn't a huge investment if you want to try one to see how it might work for you.
 
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I mostly make 1 & 2 kilo batches, so mixing bowls & cups & silicone utensils from Dollar Tree work great. If I'm ever able to go bigger I would buy good restaurant grade containers. The Webstaurant store seems to have a lot of good stuff and reasonable prices, so if I didn't have a local restaurant store that's open to the public - or if I'm refusing to people that week - that's where I would start. I've tried buying containers from Amazon but usually end up with the wrong type of plastic.
 
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Oh no, not this subject again. lol We have so may threads and posts on this issue going back years.

In all my research and listening to different experiences of various chemists and those that work in labs who have had their glass lye storage bottles dissolve bit by bit over time from the lye......but more importantly, listening to the many soapers who have had their Pyrex shatter on them when working with lye.... my own stance, as well as the official stance of the Admins here SMF remains the same....soaping with glass is just asking for trouble. I liken it to playing a game of Russian Roulette. You may have nothing happen for several soaping sessions and be lulled that all the warnings must be bunk, but we've had one too many soapers chime in with their experiences that have proven otherwise, and so it's not something we recommend. If anyone wants to do it anyway, that's their own business and they are certainly free to take that risk and do so, but we will continue to warn of the dangers.

Here are some links to just a few of our members have posted in regards to their experiences of having had their Pyrex go kaboom on them when soaping, or in the dishwasher, or just sitting in the sink or cupboard (there are more, but these are enough to suffice):

Forum member BlueberryHill from 2015:


From forum member Raha from 2010:


From forum member Deda from 2010


Forum member Paillo from 2011:


Forum member Candybee from 2013:


Forum member Newbie from 2016:


If the Dish Forum was still around, I could send you a bunch of links to shattered Pyrex experiences during soaping from the members there, too, but unfortunately they are offline.

Anyway, like I've posted before in other threads, glass is pretty strong stuff, but there are four things that are its 'kryptonite (if I can borrow from Superman jargon), i.e., things that aggressively attack it and weaken its resistance, causing it to actually corrode and even dissolve layer by layer:

1) Hydroflouric acid
2) Concentrated phosphoric acic (when hot or when it contains flourides)
3) Hot concentrated alkali solutions of at least 9 pH (lye has a pH of 14)
4) Superheated water

Of the above 4 things, the thing that concerns us as soapmakers of course is #3, alkali. Alkalis affect the surface of glass by directly attacking the silica that the glass is made of, leading to its dissolution, little by little, over time as the surface of the glass is repeatedly exposed to the alkaline solution. And the rate of corrosion increases if the hot alkaline substance is agitated, such as when being stirred.

The above corrosion happens to all glass with the repeated exposure to hot lye solution- even borosilicate. See the following safety sheet on borosilicate glass....scroll down to 3.3 under Chemical Composition:
https://www.scilabware.com/en/glass-types-properties
Here's a quote from that link: "Only hydrofluoric acid, hot concentrated phosphoric acid and strong
alkaline solutions cause appreciable corrosion of the glass." [emphasis mine]


Also this in regards to borosilicate glass: Glass Properties
"Resistance to alkaline solutions is moderate and strong alkaline solutions cause rapid corrosion of the glass, as does Hydrofluoric acid and hot concentrated Phosphoric acid." [emphasis mine]


See also the following in regards to how glass corrodes: Glass corrosion "Glass is resistant to most acids but is highly susceptible to attack by alkaline materials, especially a concentration of OH- ions giving a pH greater than 9.0. The result is an attack of the network forming silica-oxygen (Si-O) bonds, leading to dissolution of the glass surface." [emphasis mine]

While it's true that borosilicate glass is stronger and more resistant and takes a longer time to weaken than soda-lime glass, its still chemically vulnerable to concentrated alkaline solutions and will dissolve bit by bit with every exposure until it reaches the point of no return, aka, 'kaboom!'. The problem is that it's impossible for any of us to know when the shattering day of reckoning will arrive until it actually arrives. You may be willing to take that risk, and that is your choice, but I for one will continue to 'proselytize' about it so that those who are new to the craft and haven't yet been made aware of this issue will at least be able to make an informed choice when deciding what kind of vessels to use to mix lye or in which to soap.


IrishLass :)
Thank you Irish Lass. It happened to me, and let me just say that is one heck of a mess to clean up. Glass shards and hot lye solution are not a fun combination. Especially on the dining room table. I’ve been proselytizing for years and I would say most people just don’t believe it can happen. This happened way back in 2013 when I was making soap for only about a year. I had worked in a chem lab in college and we used borosilicate glass all the time with no problems, but as you said, you just never know at what point it will shatter. Thanks for your diatribe!
 
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Thank you so much, to all of you for your kind assistance.

@dibbles, I have been coveting the Oxo bow for sometime but have not been able to source microwave usage information for it. I contacted my local kitchen store who advised against microwave use. I’m glad that it’s working for you.
I will look into the dimensions of the jug you listed to see if it fits in the microwave oven, thank you so much.

In the meantime I used a few buckets on Saturday with the #5 rating and was pleasantly surprised.
The oils melted in a fraction of the time of the Pyrex, in the microwave.
And of course as Earlene mentioned, there was no issue of hot and heavy glass jugs/bowls.

I am so glad and thankful that this subject has reappeared.
For myself as an inexperienced soap maker, this forum is a mammoth source of information and education.

Looking at some YouTube videos where soakers use Pyrex, I did not know better.

Thank you all once again.So grateful for your sharing
 

Motherofmoe

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So “she” is an actual chemist/scientist with degrees.
She is referring to hobbiests who make their own soap and yes glass is as safe as glass can be in the hands of whomever is using it.
 

TheGecko

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So “she” is an actual chemist/scientist with degrees.
She is referring to hobbiests who make their own soap and yes glass is as safe as glass can be in the hands of whomever is using it.
And your point is what?
 
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