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Does anyone make their own silicone molds? I have questions for you Answered

I was looking for a rectangle silicone mold to use for cold processed soap. I saw several that were called "soap mold liners". They were used to line or fit inside wooden soap molds. Right now if a soap maker uses a wooden mold, a lot of time is spent lining the mold with plastic wrap, or freezer paper......usually with less than stellar results. Silicone seems to be the answer. When I finally tracked down the silicone liners, I also found out that this company is no longer in business.......

My DH made me a wonderful mold out of a large thick plastic (HDPE) cutting board, BUT while the soap doesn't leak out, or react to the plastic, it IS difficult to get the soap to "let go" of the plastic, so I end up lining it just to simplify the process. I would like to make my own liner from silicone IF I could get some direction form someone in the know. I have seen directions on the internet, but I think those are mainly ads to sell their product.

My questions
What silicone (brand) is best for a first timer?
which release agent (brand)?
could I use the actual HDPE soap mold as the outside of the mold without the silicone or release agent hurting it?
can wood be used as the "mold" to create the cavity? Doe the wood have to be treated?
where would I find these products
Any other "suggestions" or advice?



first time casting using the homemade silicone putty. If i want to cast my mold from a wood carving made in balsa wood, can i coat it with wood glue and use that as a surface that will help the mold come off easier after drying?


It looks like it is already heavily coated in some areas.
Thin the glue a little bit and apply with a brush for the fist coat.

Let dry completely, usually wood glue turns clear when dry.
If you still have holes in the surface or very uneven bits you can apply another coat.
A spray with bees wax should also work just fine.

ok thank you i will give it a try. Are there any ither tips that would help me do this correctly?

Your only problem is to get the moulding material liquid enough so it fills everything correctly.

If you don't want to make something permanent to keep the mould in shape during curing use putty - you know the cheap stuff our kids love to play with...

the mold got caught on some uneven carves and messed it up but i am using my dremel with a diamond tip bit for smooth sufaces so test number two should work better. I will post pictures soon with v2

This is coming from one that hasn't any experience in what you do, but a thought came to me, and I figured I would ask.

As far as "releasing" the soap, would a very light coating of oil (say from the cooking spray cans used for pans) help? Or do you think that would be detrimental to the soap itself?

actually any cooking oil type coating would only make it worse. That oil would just become part of the saponification reaction.....becoming soap as well. I have used petrolium jelly which is NOT a fat, but it's m-e-s-s-y, and can be blotchy

Yes, you are right, and I had forgotten that (not that I've made soap, but I have read about the process).

Question: would a thick Saran Wrap type to line it work?

One of the reasons things stick is because of "pits" in the material that the fluid flows into and then congeals. Even some of the silicons and polymers would have some of that. BUT if you can find one that dries VERY "glass-like" with very little or no roughness on the surface, that as a coating may work pretty well.

Hey Goodhart, yup any plastic wrap will work.....even really thin stuff.....but lining molds is NOT something I enjoy! I actually have stopped using one of my wooden molds because you HAVE to line wood....at least my plastic mold doesn't HAVE to be lined, the soap just has to be cut out of it (you're right it's because the plastic isn't perfectly smooth....it was a USED cutting board before my DH refashioned it into a mold for me)

a couple of stores WANT to sell my soap, but they want nice uniform bars (what fun is that???) instead of my usual "rustic" bars. That's why I need something that has nice, sharp, square corners, that I don't have to spend a lot of time fooling with. The mold/liners online that fit the bill are very high priced. Loaf pans used for baking are too wide and short, with rounded corners and don't hold enough raw soap.

Thanks, when I'm a little LESS distracted, I'm going to look at these....I have NO experience with resins etc, so the more info the better! Thanks for your help!

Well, I hope I have actually been of some help.. :-) and not misled you in any way

I'm really out of my element her, but I'm wondering if WD-40 could be used as a release agent? I (personally) love the smell.

lol MaryT... yeah... I "wonder" a lot. ;-)

OMG I never thought of WD40.....it MIGHT! I "wonder" a lot as well! I keep telling DH he'd "flip" if he could ever hear, what I hear in my brain.....a lot of chaos, and giggling

IIRC WD-40 has warnings on it about extended contact with skin which could become problematic. Besides that, you'd SMELL like kerosene for the rest of the day after using it :-)

Thanks Goodhart, but I think bajablue was just suggesting it as a release agent on the mold......not for me to use it in the soap. It's something to think about, and I ALWAYS am thankful when people remind about safety precautions.....or tell me that something I'm about to try has already been tried and didn't work....no need trying to reinvent the wheel. That's one of the MAIN reasons I like to post questions here! Thanks again

Wouldn't it mix a bit with the soap on the surface if used to release it? It is a petroleum product, but being an oil would have it's surface tension broken so it would mix easier than if no soap was present. I mean, you can certainly try it, but if the soap ends up smelling a little like it's been soaked in kerosene, it might not be very palatable. :-)

hahaha Yeah WD-40 scented soap would NOT do it for me, that's for sure!

I don't know if I will ever try it, but it was just a "thought".....I know that any "fat" (specifically triglycerides) would combine with the lye ( sodium hydroxide, or another strong alcaline like potassium hydroxide) to start the chemical reaction called saponification. Petroleum products won't. so that's why you can't use a spray "cooking oil" type release agent like PAM.....it just becomes part of soap!

something else to consider, what type of form being used....the "solvants" in WD-40 dissolve some plastics :-)


My hubby is used to it. Whenever I start a sentence with "What do you think about...." he knows I've got a WhAcKy idea in my head. ;-D

Methinks we're kindred spirits, MaryT! ;-)

You sound like Conker-X.

At least five times a day we have conversations that start "Daddy, I have an idea for an Instructable...", and end with a discussion on why it won't work, thanks to the basic laws of physics (or finance).

hahaha... at least he consults you.

Didn't you recently quote "It's easier to ask forgiveness than it is to get permission." ?

Maybe it was someone else. ;-)

It may have been somebody else, but it's a quote I often use!

I think posting/reading questions here is one of my favorite things, because I KNOW that if my little brain is thinking of something that probably someone else has already thought of it, and maybe tried it.....I don't like to try to "reinvent the wheel", so generally search for results here first. I'm sure doing that has save me (and my loving DH) a fortune in $$$ that would have gone down the drain trying some hair-brained idea one of us has thought of.....I SO love, love, love the idea that you must have really encouraged your kids to think creatively! I have long thought that many times children's creativity has been stifeled, in an attempt for conformity

I have thought we are, for some time now! <3

Looks like the Instructables comment gremlins are back! ;-)

I just felt a collective gasp on the hipster homeworld. Is not WD-40 the least green or organic thing to add to or use in making homemade soap? WD-40 is not something you would really want in contact with your skin and it's not suntan lotion, although I am sure many have used it as such. I have never seen a label WASH SOAP BEFORE USING but it might be a good idea.

Thanks so much, but I'm trying to get away from using paper to line my molds.......I currently don't use ANY "release" agent, unless you count wax paper, plastic wrap, or freezer paper as a "release" agent....I have tried several silicone molds that are intended for baking, and they work really well as far as releasing goes.....that's WHY I'd like to have a silicone SOAP mold/liner.
I NEED a soap mold/liner that has nice, sharp, square corners to cut down on the waste incurred when using a mold intended for baking (they have rounded corners, and are NOT really the size I would like my soap bars to be) The ones (soap mold/liners) that I have seen online are pretty pricey, and since my DH and I are "DIYers" I thought maybe the answer would be to make my own. As always I did a search here to see if anyone had posted an instructable on making a mold from silicone already....I see posting one on that subject in MY future ;-) Then I posted the question

WD-40, the cologne of choice for the discerning mechanic in your life.

I think bajablue was just suggesting it as a release agent on the mold......not for me to use it in the soap. It's something to think about, and I ALWAYS am thankful when people remind about safety precautions.....or tell me that something I'm about to try has already been tried and didn't work....no need trying to reinvent the wheel. That's one of the MAIN reasons I like to post questions here! Thanks again

When people use petrolium jelly as a release agent, that too has to be "washed" off of the soap before using

I JUST heard about a brush on latex.....I'm going to look into it.

I was also wondering if I could have DH cut a block of wood to the exact size I wanted the loaf of soap to be, then put that block into the existing wooden mold (that I currently don't use because it's a pain in the tush to line) or into the plastic mold I DO use, then pour liquid silicone into the mold and over the wood.......once the silicone was all set up then I could pull out the wooden insert and have the silicone liner fitting the mold perfectly!

NOW I wonder IF I'd have to coat/cover the wooden block with something to keep the silicone from sticking, hmmmmmm

Sounds like you have some experimenting to do, Miss MaryT! ;-D

yeah I'm afraid so....I MAY just break down and shell out the money to BUY a silicone liner and call it good. :-(

Sometimes "Time is money".  

Here are a few molds I found on eBay that seem to be what you want... and they're probably(?) less expensive than buying the materials needed to make one.  

Cubical mold

quare mold  

Rectangle mold

You're probably right I've seen these but have hesitated, because they're made in China....I haven't had stellar results with other things I've ordered from China (another company). I'm probably going to try my hand at making my own silicone mold, but maybe NOT right away. I'm rethinking the whole "selling" thing, IF the store insists on more uniformity than I'm comfortable with

BTW I started to make a new Instructable.....but couldn't snap my pictures, while pouring the soap, and DH was no where to be found!

Here's the finished result: The first pic is just showing the pretty swirls, when I trimmed off the "ugly" ends

First cuts Watermelon soap.jpgWatermelon swirled soap.jpg

That's soap?  It looks delicious... I want to eat it! ;-)

yup, soap....it smells w-o-n-d-e-r-f-u-l as well......watermelon! but you wouldn't want to eat it....you'd sure be "blowing bubbles" hahaha


Child blurts out naughty word... Mom threatens to wash potty-mouth out with soap.

Child: Use the bar that's Watermelon-scented... or else I'll report you for child abuse!


What about mineral oil as a release agent?

actually, that MIGHT work......but I'm really wanting to make a silicone mold/liner. HOWEVER I may try this in the mean time.......THANKS

Oh...your OP asked about release agents...? Anyway, I've had success in using it with epoxy resin and plastic molds.