Is Pyrex all right for one use?

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Zany_in_CO said:
Yeah, me too, Helenz, and for much longer than that. I can't help but wonder if all this hype about glass being dangerous vs plastic being safe is "speaking from personal experience" or based on some urban legend from long ago that's just been passed down from generation to generation.

PS: My apologies to all who are offended by this difference of opinion. No worries. I'm sure this post will be deleted tout suite. :)
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I don't think that it will be, but your reasoning is still very flawed.

I have once needed my seatbelt in my car. Once, in 16 years of driving. Many people have never needed it. Does that mean that they shouldn't wear it? Other people have been hurt or killed because of not wearing one, but that's not personal experience, right?

I have seen the state of a glass bottle which stored a weak lye solution for food use for a few months - there was a cloud of dissolved glass at the bottom of the bottle and the glass was visibly different from the glass above the solution.

Lye does etch most glass over time.

I hope that you never have an issue, I really do. But that does not make it responsible for you to suggest that there might never be an issue for other people based on your personal experience. That is just irresponsible and exceedingly foolish of you. It is not your opinion which offends me, it's the fact that others could well suffer serious issues because of how you present your opinion. Which is all it is - whether or not most types of glass are damaged over time by exposure to soaping level lye solutions is not a matter of opinion, is it? It's a provable point of fact.
 
Zany_in_CO said:
Yeah, me too, Helenz, and for much longer than that. I can't help but wonder if all this hype about glass being dangerous vs plastic being safe is "speaking from personal experience" or based on some urban legend from long ago that's just been passed down from generation to generation.

PS: My apologies to all who are offended by this difference of opinion. No worries. I'm sure this post will be deleted tout suite. :)
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Unfortunately, no- it's not an 'urban legend' from long ago. One of my fellow (former) modmins had her pyrex all of a sudden shatter on her a few minutes after mixing her lye solution in it. Thankfully, it was sitting in the sink (cooling off) when it happened and she did not end up with glass and lye everywhere on her floor. I know of other soapers who have reported the same thing happening to them as well. Lye will chemically react with any type of glass, be it tempered or not. It reacts with the silica in glass, gradually dissolving it over time. The corrosion can happen rather quickly, too. Here is a demonstration of how quickly glass can dissolve when placed in molten NaOH:

[ame]https://www.youtube.com/watch?v=nmktRTHL1NA[/ame]

Granted, we do not make soap using molten NaOH and will most likely never experience anything so dramatic or instantaneous, but the corrosion/etching/dissolving/weakening still goes on nevertheless, albeit at a much slower rate.

Here is an excellent article that describes how glass corrodes:

http://corrosion-doctors.org/Household/Glass.htm


IrishLass :)
 
I've got three brand new pyrex measuring cups in my kitchen that were originally bought for making soap. Only one of them is still tagged and has ever actually been used for soaping, and it's basically just to catch spatulas and whisks so they don't drip all over everything. I'm clutzy enough as it is, I don't need the added excitement of glass spontaneously shattering.

My lye gets mixed in a stainless steel pitcher, and my soaping is done in stainless steel bowls unless it's a big batch, then I'll bring out the crock pot. I've also got assorted plastic vessels (all with either 2 or 5) for when I want to split a batch up.
 
I think most can agree that storing or even mixing your lye solution in glass is a bad idea.

But I, and I think a few other repliers, said that we just melt our oils in a glass vessel then add our lye solution to create the batter. I wonder how dangerous that is, since I assume the walls of the glass are covered in a thin layer of oil for the whole duration, and the lye is quickly mixed and diluted and begins saponification. Assuming you wash the bowl immediately afterwards, the risk seems quite low.

Eliminating the chance of risk is a valid point, but if we used that same logic in every aspect of our lives, no one would ever drive a car again... :mrgreen:

But with all that said, I will be on the lookout for some microwave safe bowls to switch over to!
 
toxikon said:
I think most can agree that storing or even mixing your lye solution in glass is a bad idea.

But I, and I think a few other repliers, said that we just melt our oils in a glass vessel then add our lye solution to create the batter. I wonder how dangerous that is, since I assume the walls of the glass are covered in a thin layer of oil for the whole duration, and the lye is quickly mixed and diluted and begins saponification. Assuming you wash the bowl immediately afterwards, the risk seems quite low.

Eliminating the chance of risk is a valid point, but if we used that same logic in every aspect of our lives, no one would ever drive a car again... :mrgreen:

But with all that said, I will be on the lookout for some microwave safe bowls to switch over to!
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I still don't think I would risk it on a regular basis. I was doing lip balm in a pyrex measuring cup and had it sitting on a towel in slight simmering water and the bottom popped and separated/broke off. Don't think I'll use lye with one.
 
No, there is no 'thin layer of oil' protecting the glass from the lye. The glass is still exposed to the high pH environment, is still exposed to NaOH. This is as much a misconception as adding SF at trace protects it from the lye in CP soap.

Really, go buy a couple of paint mixing buckets from your closest hardware store. the quart sizes are perfect for 500g batches, the 2.5 quart are perfect for up to 1100g batches. they are cheap, and you can buy lids that fit them. you could have several for under $10 US
 
kchaystack said:
No, there is no 'thin layer of oil' protecting the glass from the lye. The glass is still exposed to the high pH environment, is still exposed to NaOH. This is as much a misconception as adding SF at trace protects it from the lye in CP soap.

Really, go buy a couple of paint mixing buckets from your closest hardware store. the quart sizes are perfect for 500g batches, the 2.5 quart are perfect for up to 1100g batches. they are cheap, and you can buy lids that fit them. you could have several for under $10 US
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Ideally, I'd like to find a microwave safe container with a spout that could fit 2-3lbs of batter in them. I'll be on the hunt.

Are there any studies out there that explicitly say that oil residue disappears from the glass when you add your lye solution? I'm just curious. Maybe DeAnna will chime in!

I've always heard that it's important to slide your spatula along the sides of your bowl, instead of just SBing, because oil residue can remain and it's important to incorporate it all.
 
toxikon said:
Ideally, I'd like to find a microwave safe container with a spout that could fit 2-3lbs of batter in them. I'll be on the hunt.

Are there any studies out there that explicitly say that oil residue disappears from the glass when you add your lye solution? I'm just curious. Maybe DeAnna will chime in!

I've always heard that it's important to slide your spatula along the sides of your bowl, instead of just SBing, because oil residue can remain and it's important to incorporate it all.
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the 2.5 quart containers are microwave safe and will hold 3 lbs. they are flexible enough that you can form a spout by squeezing the sides.

It important to make sure your batter is evenly mixed - but it isn't because of oil residue - its just to make sure all of your oil is mixed in. And scraping the sides again exposes your glass to unreacted lye - because we KNOW that saponification has not finished in CP for several hours.

Hey, if people are dead set on doing dangerous things, I won't stop them. I also won't feel bad when the glass shatters - or it slips and falls on the ground and breaks so they have soap batter covered shards of glass all over.
 
From a chemistry point of view - In the lab we have all Borosilicate glass (Lab-Grade pyrex or Kimex). Lab policy is that glass may be use for working with diluted alkaline solutions or with the dilution process when resulting in a greater than 50% dilution of the alkali. Otherwise we are to use HDPE containers. I imagine that you could soap with the cheaper glass for years and years and never have a problem. However, I think this is a lot like some of the other safety discussions here, in that it probably isn't worth the risk as glass probably doesn't have any real benefits other than availability and familiarity.

FYI - The paint mixing buckets (which come in various sizes) available at home improvement stores like Lowe's and Home Depot are usually HDPE (#2) or Polypropylene (#5) plastic. That is what I have been using for both the lye solutions and mixing. I think I only paid about a dollar or two for each so I have spares and don't have to worry about not having enough containers while working.
 
kchaystack said:
the 2.5 quart containers are microwave safe and will hold 3 lbs. they are flexible enough that you can form a spout by squeezing the sides.

It important to make sure your batter is evenly mixed - but it isn't because of oil residue - its just to make sure all of your oil is mixed in. And scraping the sides again exposes your glass to unreacted lye - because we KNOW that saponification has not finished in CP for several hours.

Hey, if people are dead set on doing dangerous things, I won't stop them. I also won't feel bad when the glass shatters - or it slips and falls on the ground and breaks so they have soap batter covered shards of glass all over.
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I'm not trying to argue or say that we should take risks in soapmaking by any means... I'm just curious about the science behind soap batter + glass, that's all. It's an interesting topic.

It is kinda funny that Soap Queen uses glass for all their tutorials if it's so unsafe, considering that's where most new soapers get their info from. There must be tons of people out there using glass and you really don't hear many horror stories and many people seem to be unaware of the risks.

I trust the judgement of the experienced folks here over SQ any day, so I will make the switch. I just wonder what the actual "odds" are. Is there a 1:50 chance of glass etching or 1:100,000? Inquiring minds and all that... :D
 
toxikon said:
It is kinda funny that Soap Queen uses glass for all their tutorials if it's so unsafe, considering that's where most new soapers get their info from. There must be tons of people out there using glass and you really don't hear many horror stories and many people seem to be unaware of the risks.
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She also talks about soap 'nourishing' your skin, and being 'moisturizing'.

There is another YT soaper who master batches lye in old pasta sauce and pickle jars. And I KNOW those will explode just by sudden heat changes - because it has happened to me more than once.
 
Whether or not a pyrex container will "explode" is a moot issue for me. What is of more concern to me whether I'm willing to risk cleaning up any spill of lye or soap batter mixed with glass shards ... or if just the spill itself is sufficiently bad enough.

It only takes a small mistake when making soap, and ~~oops!~~ there's a container of stuff on the floor or counter. If the container is plastic or metal, there won't be shards. If glass, there are likely to be shards and there will be a much higher risk of injury.

NaOH on normal skin is bad enough ... I am not going to put myself or anyone else at risk for NaOH in a cut or scrape due to broken glass, however small the injury might be. This is a no-brainer safety issue for me, so I don't quite get why there's any debate about this matter.

***

As far as whether there is a film of fat "protecting" the glass ... nope, this is a myth.

What might be the root of this myth is the engineering idea of a specific type of flowing liquid (or gas) passing slowly through a pipe. In this specific situation of "laminar flow", there will be a non-moving layer of fluid right against the pipe.

Problem is, once the laminar flow condition is disturbed by any turbulence (stick blending, anyone?) or any other kind of action (scraping with a spatula, perhaps?), then there is no laminar flow and no "protective" film against the pipe.

So you ask -- then why is a soap pot so greasy? I agree it's greasy from the fats ... but it's also covered with residues of active lye ... and residues of the other ingredients in your soap batch. Just because the fat is more visible and harder to wash off than the other stuff doesn't mean the other stuff isn't there.

Think about sauteing onions or chops in a fry pan. The film of olive oil or other fat on the pan doesn't eliminate food residues from sticking to the pan, which tells me that the fat doesn't form a perfectly protective film on the metal of the pan. If it did, there would be no reason for non-stick coatings on saute pans. Same idea with a soap pot.
 
To me, decisions are a combination of what is possible and the consequences of it happens. I wouldn't point a gun that I was sure was unloaded at my head and pull the trigger because the consequence is unacceptable no matter how minute the chance. Conversely, if the consequence is low - say a water gun - I will accept a higher probability of mishap.

IMO, hot lye solution in glass has consequences that are unacceptable at any likely hood of occurrence, compounded by actually being the situation most likely to fail. Perfect storm.

The big pyrex batter bowl, though is both less dangerous if something happens and less likely to happen. We've all spilled batter and lived to tell of it, right? That's the worst that happens if a bowl falls - maybe just a larger scale. As I said from the beginning, though, it's still not best practice but I'm comfortable with the risk to potential balance for now.
 
When I was 11 I poured hot oil into a Pyrex jug and it shattered over my foot. I was home alone but luckily knew enough to put my foot in a bowl of cold water until my parents came home and took me to hospital. I'll never forget it.

I subsequently learnt that Pyrex (even the good stuff) isn't designed for direct heat or sudden temp changes. I hope someone learns from my experience.
 
toxikon said:
Ideally, I'd like to find a microwave safe container with a spout that could fit 2-3lbs of batter in them. I'll be on the hunt.

Are there any studies out there that explicitly say that oil residue disappears from the glass when you add your lye solution? I'm just curious. Maybe DeAnna will chime in!

I've always heard that it's important to slide your spatula along the sides of your bowl, instead of just SBing, because oil residue can remain and it's important to incorporate it all.
Click to expand...

I've picked up a couple large mixing bowls with pour spouts, #5 recycling code, at dollar tree that hold 3+ pound batches.
 
How bad are those jugs that came out about 5 years ago.
I still have one but I rarely use it.
You can't pour cup of anything without spilling half, doesn't matter how much you try.
They're certainly not for soaping unless you want half of your soap batter on the bench.
I think they've fixed the design again. I can't see those terrible jugs in shops anymore. I love pyrex but those were such a fail haha.

I mainly use mine for marinating stuff, as salad bowls, quick microwaving, cake batter etc.
I have few that I bake in but 15 years on and I've never had an issue.
 

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