Milk soaps and PVC moulds

[soapsmurf]

Sorry if this topic already exists. I searched and didn't find.

I know that milk soaps will heat up more, but I really want to use PVC piping as a mould. My question is whether this is suitable and if so, how short should I cut the piping so as to prevent volcano soap?

 

[xyxoxy]

I do PVC molds almost exlusively and have found 15" to be a good length. That doesn't exactly answer your question about milk soaps but then you don't have to fill them up all the way.

The reason I like 15" is because they fit perfectly in my fridge when I prevent gel. I also use plastic chopping mats as liners and the ones I get from Dollar Tree are exactly 15" long... so I only have to cut them for width.

15" x 3" PVC is also just about perfect for a 2KG batch of soap.

ETA: Oops... I meant a 1KG batch which is just about the same as 2 pounds.

 

[xyxoxy]

I cut my plastic mats exactly to the size of the inside of the PVC and they stay in place by themselves... no need to tape.

I do not make milk soaps so I can't really advise you on that.
I usually refrigerate to prevent gel but sometimes not. I've never had a volcano soap... just sometimes a slight expansion in the mold during the first 24 hours (maybe 1/4" - 1/2"). I have covered and wrapped the PVC in blankets to gel with no bad results.

I will say I've tried CPOP a couple of times with the PVC and the extra heat caused a slight seperation (oily surface on the soap).

I suppose it all depends on your recipe and the temps of your oils. I do tend to soap rather cool and use a pre-mixed lye solution at room temp. I usually start around 90F. My batches never get over 120F and that's after the lye and all other ingredients are added. Not because I've had problems with overheating but just because I like that process and hate to mix up lye each time I make soap.

 

[dolly777]

I use 18 inch PVC all the time to make GM soap. I have had no problems. One tip I will give you about milk is this. Do a water discount (I do at least 40%) and add the milk to the oils not the lye water. Let your lye water cool to 90º F and same for oils. You will get a nice pale color bar and you will have no problems with overheating. I do this for all my GM soaps no matter what mold I use.

Here is a pic of my GM soap (this one is from a wooden mold) but my PVC ones have the same color.

Hope this helps.

 

[soapsmurf]

I use 18 inch PVC all the time to make GM soap. I have had no problems. One tip I will give you about milk is this. Do a water discount (I do at least 40%) and add the milk to the oils not the lye water. Let your lye water cool to 90º F and same for oils. You will get a nice pale color bar and you will have no problems with overheating. I do this for all my GM soaps no matter what mold I use.

Here is a pic of my GM soap (this one is from a wooden mold) but my PVC ones have the same color.

Hope this helps.

Great! Thanks I also add to the oil rather than lye. That seems to be working ok for me. The only mishap I've had was when I used lye water that wasn't down to temp. Bad me. I will remember to do a water discount. Your bars look lovely!

 

[naturesphilosophy]

I suppose it all depends on your recipe and the temps of your oils. I do tend to soap rather cool and use a pre-mixed lye solution at room temp. I usually start around 90F. My batches never get over 120F and that's after the lye and all other ingredients are added. Not because I've had problems with overheating but just because I like that process and hate to mix up lye each time I make soap.

Not to derail this thread, but you caught me with the pre-mixed lye solution. How do you know how much of it to use? or are you just making one recipe with the same lye mixture all the time and mixing enough for a certain number of batches? That's a great idea

 

[xyxoxy]

Not to derail this thread, but you caught me with the pre-mixed lye solution.

Here is a thread where Paul explains it perfectly... and since he's the one I learned it from he deserves the credit.

http://www.soapmakingforum.com/forum/viewtopic.php?t=5399