Glass vs Plastic for Soap Batter

[earlene]

Yes, sorry, I wasn't advocating for glass; the downsides seem to outweigh any upsides (weight, breakability, etching, etc. etc.). I meant for mixing lye: I know that it's important to have the right type of plastic container to bear the heat of the lye water, but I didn't think it was as crucial to have a batter pot that was made of HDPE plastic, since the oil + lye water are cooler.
Does that make sense?

It does not have to be HDPE plastic, no. PP is fine.

See this section from DeeAnna's classicbells site (link to entire article):

High density polyethylene and polypropylene are best. Most people prefer containers made from high density polyethylene, HDPE, with a #2 recycling code, or polypropylene, PP, with a #5 recycling code. Containers with these codes have excellent resistance to lye up to the maximum 50% concentration. They are heat resistant enough to withstand the heat of a hot lye solution and are often sturdy enough to be a durable, safe container for lye.

 

[MGM]

It does not have to be HDPE plastic, no. PP is fine.

Right. My *lye* container is PP5, but my *batter* container is....I have no idea. I didn't look cause I didn't think it was important because it doesn't get as hot.

 

[jcandleattic]

Right. My *lye* container is PP5, but my *batter* container is....I have no idea. I didn't look cause I didn't think it was important because it doesn't get as hot.

Hot really isn't the issue - there is still unreacted lye in soap batter than can/will react to plastic that isn't rated for that particular chemical. If you have not had any issues, then yours must be the right type of rated plastic for caustic material.

 

[DeeAnna]

...I meant for mixing lye: I know that it's important to have the right type of plastic container to bear the heat of the lye water, but I didn't think it was as crucial to have a batter pot that was made of HDPE plastic, since the oil + lye water are cooler.
Does that make sense?

I understand where you're coming from, and I was responding to your concern, but I realize I didn't explain myself well enough.

It isn't just the temperature that needs to be considered -- it's also the high pH. Soap batter is every bit as nasty alkaline as lye solution.

edit: I can see that I need to revise my article (the one Earlene linked to in her latest post) to broaden the language to include containers for soap batter as well as for lye solution.

 

[szaza]

Oh my, looks like I'll need to invest in stainless steel bowls for hpop.. thanks for starting this thread @LilianNoir !

 

[MGM]

Oh I'm glad we clarified, as I thought it was only the hot that was a problem. I will double-check the bottom of my vessel and perhaps invest in a second Dollar Store purchase

 

[Mobjack Bay]

I have had really good luck finding stainless steel bowls at the thrift store, but most of them are too big for the size of the recipes I’m making right now. I didn’t pay more than $2-3 for them. They’re deep batter bowls, not wide like salad bowls. I looked and looked and looked for a pitcher and finally gave up and ordered one from Amazon. I also bought a bunch of silicone spatulas at the thrift store, but my favorites for soapmaking turn out to be long flexible icing spatulas that I ordered from Amazon (norpro, I think).

 

[JasmineTea]

I have multiple sizes of stainless steel measuring cups that I use for soapmaking and personal care making. Here's a 2-qt one from Amazon: https://www.amazon.com/gp/aw/d/B010PJUD98?psc=1&ref=ppx_pop_mob_b_asin_title

I like these because they are not heavy, are not breakable, can be heated in a pot of hot water or direct heat, have a spout and handle, and are made of a thin enough metal that the pour spout is not thick and cumbersome to use.

 

[Mobjack Bay]

I have multiple sizes of stainless steel measuring cups that I use for soapmaking and personal care making. Here's a 2-qt one from Amazon: https://www.amazon.com/gp/aw/d/B010PJUD98?psc=1&ref=ppx_pop_mob_b_asin_title

I like these because they are not heavy, are not breakable, can be heated in a pot of hot water or direct heat, have a spout and handle, and are made of a thin enough metal that the pour spout is not thick and cumbersome to use.

That’s exactly what I bought!

 

[linne1gi]

Yes, sorry, I wasn't advocating for glass; the downsides seem to outweigh any upsides (weight, breakability, etching, etc. etc.). I meant for mixing lye: I know that it's important to have the right type of plastic container to bear the heat of the lye water, but I didn't think it was as crucial to have a batter pot that was made of HDPE plastic, since the oil + lye water are cooler.
Does that make sense?

It’s not actually the heat of the lye water (although that does factor in somewhat), it’s the fact that the lye actually etches the glass. That’s why it’s a bad idea to use glass for any part of the soap making process. The soap batter still has active lye, even after trace, the lye is active and will etch the glass. Lye etches plastic as well, but plastic holds up better, maybe in 50 years or so the plastic will break!

 

[earlene]

It’s not actually the heat of the lye water (although that does factor in somewhat), it’s the fact that the lye actually etches the glass. That’s why it’s a bad idea to use glass for any part of the soap making process. The soap batter still has active lye, even after trace, the lye is active and will etch the glass. Lye etches plastic as well, but plastic holds up better, maybe in 50 years or so the plastic will break!

Well, that depends on the plastic. I've had low-grade plastic (not lye safe plastic) develop cracks that leaked lye out the bottom in only a very short time - probably a couple of months. That was before I stated paying attention to the type of plastic I was using. And of course, I always made sure to mix lye with the container seated inside my kitchen sink, so there was not problem with the spill. I suspect it might have taken longer if that was the same plastic I used for mixing soap batter, but it was just for mixing lye.

 

[Susie]

So far, I've only had one spill from plastic failing me. And it was not much, and easily transferred to another container. Knock on wood.

Having that one, however, taught me to check the bowls and containers before using. I just run cold water in it, and push with my fist. If there is any leak or give to the plastic, in the trash it goes.

It's never a failure if you learn something.

 

[LilianNoir]

Oh my, looks like I'll need to invest in stainless steel bowls for hpop.. thanks for starting this thread @LilianNoir !

You're very welcome! I'm glad I did too, as it seems to have helped several people.
I'm a little shy about asking "newbie" questions sometimes but as teacher I know well the old adage "someone else will have that question!" is quite true.

 

[melinda48]

Well, that depends on the plastic. I've had low-grade plastic (not lye safe plastic) develop cracks that leaked lye out the bottom in only a very short time - probably a couple of months. That was before I stated paying attention to the type of plastic I was using. And of course, I always made sure to mix lye with the container seated inside my kitchen sink, so there was not problem with the spill. I suspect it might have taken longer if that was the same plastic I used for mixing soap batter, but it was just for mixing lye.

#5 plastic works great and is not expensive.

 

[earlene]

#5 plastic works great and is not expensive.

True that it works great, which I have pointed out in previous posts, however I was responding to linne1gi's statement that plastic wouldn't break from lye in about 50 years. I was pointing out that it depends on the type of plastic used.

I use #2 and #5 plastic with no problems whatsoever, but the cheap plastics (cheaply made) will deteriorate quickly. That was my point.