What is your lye mixing container made out of?

[IrishLass]

I chose to use an old coffee carafe I had from a coffeemaker I no longer use figuring they were made to withstand hot temperatures for sitting on a hot plate for hours on end.

Where a highly alkaline substance such as lye is concerned, it's not just heat that causes the shattering problem. It's the etching part that'll spell its sure doom. And the scary part is that you can't predict when the glass will shatter. It's much safer to use PP #5, HDPE or the stainless steel.


IrishLass

 

[soapopera]

I've been using stainless steel that say that on the bottom of the pots, never anything less. But lately I've noticed when I scrape the last of the lye water out of it there's a little tich of grey. Like some of the metal is coming off. Not enough to affect the color of the soap or anything but it kind of bothers me.

Today I've noticed my plain unscented batches had a strange 'yellowing' on the poured surface. I'm quite sure it's DOS developing as there's a slight smell of rancidity coming off from it. The funny thing is the rest of the bars are free from this yellowing. I'm cracking my head as how did this only forms on the poured surface? I've thought maybe it's my lid which might have impurities which dropped on the surface. But after finding this thread, I'm beginning to think it could be from my SS pot. I scrape the last bit of soap from the pot into the mold. And I'm wondering could this be how only the surface starts to yellow. Also I notice my pots sometimes have 'watermarks'. The SS pots I've got was suppose to be from a reputable brand. But now I'm thinking to try switching to everything plastics or silicones (inc spoons) to see if I still have this problem.

 

[soapopera]

By the way, anyone have any insight on melamine ware for mixing oil and lye?

 

[Guest]

ANY kind of glass will shatter or even explode from rapid temperature change. If enough lye is added at once, to a glass container with cold water, or in an ice bath, it has high risk of shattering. Its the same reason ice cubes crack in your beverage, and the same reason you're not supposed to pour hot water on a frozen windshield. Rapid cooling produces the same effect.

You can use pyrex to mix your lye, if care is taken to add it slowly so that the temperature gradually rises instead of spikes. Its not the lye itself or the high temperature that is causing these accidents, but the rapid spike in temperature. Heat causes molecules to vibrate and objects to expand. The rapid spike in temperature causes the surface of the container in contact with the heat to expand faster than other parts of the container and they break apart from the stress.

B-B-B-Bill Nye the Science Guy!

 

[IrishLass]

ANY kind of glass will shatter or even explode from rapid temperature change. If enough lye is added at once, to a glass container with cold water, or in an ice bath, it has high risk of shattering. Its the same reason ice cubes crack in your beverage, and the same reason you're not supposed to pour hot water on a frozen windshield. Rapid cooling produces the same effect.

You can use pyrex to mix your lye, if care is taken to add it slowly so that the temperature gradually rises instead of spikes. Its not the lye itself or the high temperature that is causing these accidents, but the rapid spike in temperature. Heat causes molecules to vibrate and objects to expand. The rapid spike in temperature causes the surface of the container in contact with the heat to expand faster than other parts of the container and they break apart from the stress.

B-B-B-Bill Nye the Science Guy!

But it's not only the temp change that makes using glass - even household Pyrex- dangerous for mixing lye solution. What makes it doubly dangerous is how alkaline substances with a pH of 9 or greater rapidly corrode/etch glass (lye has a whopping pH of 14). Depending on how alkaline the solution is and how resistant the glass is, the corrossion will either be hastened or happen more slowly, but it will happen nevertherless. As one chemistry professor explained it to a fellow soaper on another forum, once the tiny etches have formed, residual sodium hydroxide particles can get trapped or wedged inside those etches and remain even after washing. The trapped sodium hydroxide particles then react with moisture in the air, setting off tiny chemical reactions that cause the etches to form micro-cracks that are nearly invisible to the naked eye, but which can be more clearly seen with a microscope. Over time, the trapped sodium hydroxide combines itself with the glass, slowly forming sodium silicate, which gradually compromises the integrity of the glass even further, until one day as you are mixing another batch of lye solution, 'KABOOM!'- shattered glass soaked in caustic solution everywhere. It may not have happened to you yet, but it has happened to enough soapers that our warnings against using glass for mixing lye solution is more than justified. I know of at least one soaper who even reported their trusty Pyrex lye solution mixing container (at least up to that point) shattering as it was just sitting high and dry right in their cupboard.


I've posted the following link before by the National Association of Corrosion Engineers earleir in this thread, but I'll post it again:
How Glass Corrodes

It explains how alkaline and acid substances corrode and weaken glass.


IrishLass

 

[Stinkydancer]

I have been using the same Rubbermaid pitchers for ever now- they hold up well.

 

[marilynmac]

Just marking this thread for me because I've looked it up about 5 times already, and it's hard to find.

 

[DWinMadison]

I use a cheap plastic container from Dollar General. Never had a problem. Guess I need to check the type of plastic it is.

 

[reinbeau]

I have a 50 ounce stainless steel pitcher I bought on Amazon for $14. I never wash it. I just rinse it well, let it air dry, and make another batch. Never have any contamination issues. I'm going to buy another one for resins in the lye, cuz you'll never get it clean again

 

[Consuela]

......the tupperware cereal storage containers my mom gave to me...

(she knows...but I still feel slightly guilty because well...you know Mom's and their Tupperware...)

I usually wash them at the end of my soaping session, and rinse them well - they haven't clouded - and the plastic is realy thick. I also use Rubbermaid pitchers too.

I have used the cheap ones from the dollar store - BUT.... one day when I put my thermometer into the solution to check, I left the thermometer in there. Came back half an hour later to lye leaking all over my counter..... Turns out it must have gotten so hot and soft - that the pointy end of the thermometer poked a hole in the bottom of the cheap container...

So.... no more of that...

 

[Susie]

I have 2 stainless steel bain marie type containers I got at a restaurant supply store. Works a charm, and being stainless, I can use them as double boilers or as an insert for my crockpot, etc. Should never have to replace them. Made sure a magnet stuck to them before buying, though.