CPOP with a silicone mold? Any tips for gel phase?

Discussion in 'Lye-Based Soap Forum' started by ahauer88, May 7, 2019.

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  1. May 7, 2019 #1

    ahauer88

    ahauer88

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    Hi all,

    I'm really excited to get started on my newest batch of soap this weekend. I've done a few, and while I liked how the batches generally looked (and smelled), I've gotten a partial gel phase and it's been disappointing.

    I guess, bear in mind I was soaping in my garage last time and it got quite cool so that was probably my issue.

    I've been reading about CPOP as a way to pretty much guarantee gel phase, but I've heard it's not to be done with a silicone mold. I have a rectangular mold (I think it's 48oz). I don't want to end up with a gigantic mess or ruined soap in my oven, but I'm intrigued, and I have seen some accounts of people who have tried it with success. I'm wondering if any of you are hiding out here :) what's your CPOP in a silicone mold success story? One of the issues described is bubbles forming on the edges of the soap as it essentially "boiled", I'm wondering if I could trim down the soap to get rid of those or how deep they go. I'm also thinking, the lowest setting on my oven is 170 - maybe I could get this to work if I left the door open for a bit before putting the soap in.

    Otherwise, have you all had good luck with bringing the soap inside and covering it? Husband was not very happy about me wanting to bring the soap inside the house, but maybe I could convince him. I'd just hate to put in all the work again just to be disappointed with another partial gel.

    Thanks a lot!
     
  2. May 7, 2019 #2

    jcandleattic

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    Keep your oven on low - pre-heat to 170 or it's lowest setting then once it's pre-heated and before you put your soap in the oven - turn the oven off! If you do this, your soap should be fine with no adverse affects unless you are soaping very warm AND use a heating scent oil.

    If the soap gets too hot in silicone you can get pock marks, OR worse, it can overheat, crack or volcano.

    I'm sure others will come along with more detailed instructions and help.

    Good luck!
     
  3. May 7, 2019 #3

    Kamahido

    Kamahido

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    All my molds are silicone and I use the Cold Process Oven Process method every time. Made hundreds of batches that way. The melting point of silicone is pretty high, so I'm not worried about it making a huge mess.
     
  4. May 7, 2019 #4

    penelopejane

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    Use a thermometer or your hand to ensure the temperature of the oven, when it is turned off and before you put your soap in is about 110*F (the temperature of a warm day). Wrap your soap and don’t open the oven for 12 hours.

    You are not cooking the soap you are providing a nice cosy environment so it can retain the heat it naturally generates as it saponifies. The same results can be achieved putting your mold in a polystyrene box with a thick cover over it.
     
  5. May 7, 2019 #5

    IrishLass

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    I CPOP pretty much all my soaps, even those poured into my silicone molds. I have a couple of different silicone molds from different suppliers, each made out of different grades of silicone. The silicone molds I have from Woodfield's (now a defunct company), are pink and floppy until filled with soap, and CPOP wonderfully without any issues, even if my gel gets a little too hot, but the ones I have from Essential Depot, which are translucent white and not floppy, are prone to causing 'silicone rash' on all the surfaces of my soap touching the mold if the gel stage happens to get too hot for their likes.....which I highly suspect is linked to certain FO's.


    Yes- you can trim off the bubbles. Thankfully, they are only skin-deep. :) I have a soap planer that does a wonderful job of slicing off paper-thin layers of my soap's surface and I only need to make 1 or 2 passes to get down to a smooth surface.


    Instead of pre-heating your oven it until it reaches 170F, just turn your oven on for only about 3 minutes or so, and then immediately turn it off. If your oven is like mine (an 11 year old electric coil-top Maytag) that should get the temp to about 110F to 120F...perfect for CPOPing. That's exactly what I do. Lots of people think my oven has a 110F setting because I CPOP at 110F, but my oven does not have a preset for that low. What it does have, though, is a digital output display that shows me how hot my oven is getting as it's counting up to whatever temp I've preset it to (usually 350F). I turn it off just as soon as it shows it's reached 110F, which just happens to be 3 minutes from having turned it on.



    If your hubby is reluctant for you to bring the soap inside to your oven, you can use a cooler as your 'oven' (provided it's big enough to hold your mold). Just put something hot in it like a hot water bottle or a heating pad to get it nice and comfy warm inside it, then put your soap inside, wrapped up with towels for good measure.


    IrishLass :)
     
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  6. May 7, 2019 #6

    Techie Joe

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    Its possible to get your oven to a lower temperature than is written on the knob, but you will have to turn it on and off every few minutes yourself. It will take some of your time and effort.
    You will likely also need an oven proof thermometer, and practice first so you know when to turn it on and for how long.

    Just on a technical note about most electric ovens, they work on the principal that the power is either full on or off. The temperature is regulated by how long the power is on for. When its on for a longer time there is a hotter oven. Same with the cooking "rings", the clicking sound is them turning on and off.

    Alternatively, you can get a small table-top oven, like a toaster oven, and use a plug-type timer to regulate the heat.
    Perhaps someone with experience of these can either recommend that idea or not.
    The toaster ovens are often used to melt HDPE plastic for other projects, many you tube tutorials.
     
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  7. May 7, 2019 #7

    Techie Joe

    Techie Joe

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    Seems like we had similar thinking there ;)
     
  8. May 7, 2019 #8

    penelopejane

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    The table top toaster ovens will not do the job. The idea is to keep the environment cosy while it saponifies. An regular oven or a polystyrene box provides some insulation to achieve this.
     
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  9. May 8, 2019 #9

    KristaY

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    Depending on how your oven functions, you can just turn the oven light on. That should provide enough warmth to ensure gel. That way you don't have to worry about your soap getting too hot. I've had a few disasters doing CPOP so I don't bother anymore. But I soap inside the house so the ambient air temp is pretty consistent season to season. When it's winter, I cover with an extra towel. When it's summer, I cover with a light weight cloth. When we had 22" of snow and below freezing temps, I set the molds on a heating pad then covered with a couple of thick towels. They all made it through gel without a problem.
     
  10. May 8, 2019 #10

    earlene

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    My electric oven's lowest written setting is 150°F, however, I turn the knob to just the left of 150 to get it to heat a tad below 150°F. I also ALWAYs use my infrared thermometer in addition to the oven thermometer that resides in the oven to ensure the oven is at the temperature I want before putting in the soap. I turn the oven off, then put my cold process soap inside & cover it if necessary.

    Under the soap I usually use cardboard as a precaution so nothing could spill over onto the oven racks or to the bottom of the oven. But I don't usually make soap that has the potential to overheat or volcano. When I have made soap that was likely to overheat, I did not CPOP.

    When the soap is in the oven, I do use my IR thermometer to check the temperature of the oven walls and the top surface of the soap (unless covered, then I check the side wall surface of the soap mold) two or three hours or so later. If the soap has not sufficiently heated to ensure gel, I remove it from the oven and re-heat the oven same as before. This is usually only necessary if I make a very small batch of soap or use individual molds that I did not properly insulate inside the oven itself.

    For extra insulation inside the oven (individual molds or small batches), I have learned that full gel can be reached by adding extra insulation in the form of a towel and an inverted cardboard box on top of the soap. I generally do this at the start if the soap is quite warm to start. Then it maintains the heat inside the oven. If the soap starts out pretty cold, I let the soap warm up in the oven first, take a temp. then put the box over the top of the towel-covered soap.

    I have had no problems with any of my silicone molds in the oven using these procedures, as long as I don't let the oven get above my lower than 150°F limit.

    When I tried the 170 setting that seems to be prolific around the internet soaping suggestions, I did have problems. That's when I lowered my settings. Silcone rash is not pretty, but it can be planed off and it is still soap. However since I started using the setting below 150°, I never get silicone rash.


    Infared thermometer:

    upload_2019-5-8_6-49-35.jpeg

    Oven thermometer:
    upload_2019-5-8_6-9-43.png

    Another caveat about ovens: They often heat to HIGHER than the setting initially, then maintain the temperature they are set at IF the thermostat is working correctly.
     
  11. May 8, 2019 #11

    BattleGnome

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    All I can add to what others have said is that I put my molds on a dedicated cookie sheet. It’s old, starting to rust, and I keep it covered in at least one layer of press and seal. I’ve lined cardboard molds for CP with press and seal before (got the suggestion from YouTube) and it appears to be safe if there are any accidental spills to protect the metal of the cookie sheet and the inside of my oven
     
  12. May 8, 2019 #12

    Susie

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    I use the heating pad and heavy beach towels method to ensure gel. Or, if not making fancy swirls, I will soap with more water or soap hotter. There are many alternatives to CPOP. Although I will warn you that you can get silicone rash any time you use a silicone mold and intentionally gel.
     
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  13. May 8, 2019 #13

    atiz

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    I second the suggestion of just turning the oven light on (depending on your oven). At least for me that gets the oven to 90-100 degrees; just nice and cozy. My soaps always gel when I do that, and I have not had an overheating one yet.
     

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