Plastic egg containers - safe to use as a mold?

[kniquy]

I am new to soaping but it is always on my mind what I can try next. As I was throwing out a large plastic egg container (the ones that hold 30 eggs) I was wondering if it would be ok to use as a mold. It seems pretty sturdy but not sure if it would handle the heat of the soap curing. It did have a number 1 in the recycle triangle.

I probably answered my own question. After a quick google search for what the #1 refers to it noted that the

Polyethylene terephthalates may leach carcinogens. Probably not a good match for making soap - who knows what would leach into the soap.

Any other household items you may have just tossed but worked for at least a one time use mold?

 

[DeeAnna]

Do not ever use PET plastics for containing soap batter or lye. PET becomes very brittle very quickly when exposed to alkalis -- it disintegrates in a very short time.

 

[Dawni]

There's a thread somewhere entitled "milk cartons" that should be an interesting read for you

It's not old too so you can also still comment there if you want.

I used (and still do) a lot of household stuff before my sister bought me molds. Ice trays big n small, Pringles cans (a crowd favorite), milk cartons, margarine tubs, yogurt cups... Plastic food containers we don't wanna put food in anymore. Someone had successfully used a pizza box as a slab mold. You'll find that thread of you search too.

Just make sure to check if it's safe to use, and won't melt.

 

[shunt2011]

I am new to soaping but it is always on my mind what I can try next. As I was throwing out a large plastic egg container (the ones that hold 30 eggs) I was wondering if it would be ok to use as a mold. It seems pretty sturdy but not sure if it would handle the heat of the soap curing. It did have a number 1 in the recycle triangle.

I probably answered my own question. After a quick google search for what the #1 refers to it noted that the

Polyethylene terephthalates may leach carcinogens. Probably not a good match for making soap - who knows what would leach into the soap.

Any other household items you may have just tossed but worked for at least a one time use mold?

A cardboard box (sturdy) or milk carton will make great molds. Pringles can. Just line whatever you use with freezer paper. I used a priority mail box from the post office when I started. Wine boxes work too.

 

[earlene]

I don't know what a plastic egg carton even looks like. I don't think I have ever seen one anywhere I shop, but then again, perhaps I haven't looked that closely. More probably I've not been in shops that use them. I see paperboard egg cartons and styrofoam egg cartons and that's about it. But if as someone else mentioned, if it is PET, then you can see how well it stands up to heat by pouring boiling water into it and watch it quickly start to 'melt' or become misshapen while it shrinks. I once simply used hot tap water in a PET water bottle and it shrank right down into a little misshapen odd bottle. If my hot tap water can do that to a PET container, I am sure soap batter would not be much different.

I read the bottom of the plastic for the recycle code. If it is a 2 or 5 in the triangle, I will use it for a soap mold. If it is a 1 in a triangle (PET) then it will deteriorate with the addition of lye soap or even with hot MP soap. It can't take the heat.

 

[Dawni]

Like this @earlene

Now that I think bout it, I have tried molding soleseife in something similar. It was packaging for a Lindt Easter chocolate. You can see it in the first pic here. The egg ones might be thicker but these didn't melt. I haven't used them again though..

 

[dixiedragon]

I like 8 or 16 oz deli containers to make test batches.

https://www.soapmakingforum.com/threads/community-candle-reviews.64360/

I like the fact that I can fit my stick blender in the container.

 

[DeeAnna]

Yeah, if it's PET (recycle code #1) it's not safe around NaOH or KOH for any reason. PET decomposes really fast. It will become brittle and crack within hours or a few days, no matter how thick and sturdy the PET container seems to be (or not).

I won't embarrass myself explaining why I know this, but suffice to say I learned the hard way why alkali and PET don't mix.