Solar CPOP Experiment

[Shirley-D]

The last 2 weeks I have had a great time dabbling and testing my recipes with mixed results, but mostly good and learning by experience. I used a 1lb mold (1/2 Kilo maybe) and some milk cartons to test small batches :--)

Today there is an excessive heat warning for Arizona. It is supposed to reach 110 F (43 C) and I don't want to turn my oven on. Can you blame me! CPOP by sun anyone? Surely somebody has already done this, but I couldn't find it. After a quick search for CPOP by sun and finding nothing like what I want to do, I decided to go ahead and live dangerously.

I made a small loaf of lavender soap with 40/42 EO and buds sprinkles on top. It is just a test, but if it turns out well I would want the buds on top. There was enough batter remaining for 1 cavity mold soap.

First thing I noticed is it immediately turned a horrible khaki color. I used 1/2 tsp of Purple Playhouse from WSP. I know it is early so I hope the color improves with time. (Is that normal? Anyone know a good purple for CP soap? For another thread maybe?)

So I put the small loaf mold outside in the full hot sun with a crystal cake dome over it. I didn't insulate because I had placed it on a hot slab of granite which measured 135F with my infrared thermometer. I figured the crystal dome would act like a greenhouse and an insulator. The single cavity soap I kept uninsulated and uncovered in the air conditioned house as my control sample. I will compare them for ash and color tomorrow. After an hour I peeked and the sun soap was 159F and the single inside soap was 89F by my IF thermometer. After 2 hours the sun soap was 179F. I'm pretty excited!

I will tune in tomorrow with the final result, can't wait! Hope I don't have a volcano with shattered crystal everywhere. I just slid the dome in away from the edge a bit, just incase.

 

[AliOop]

Great idea! The only problem is that sunlight encourages rancidity (DOS). It also fades the color of the soap. But I think this could work if you covered the soap with something that didn't allow sunlight to penetrate.

PS: I don't like using my oven for CPOP ever (scent transfer ), so I put my soap on a heating pad, and place an overturned, insulated box over it. With your wonderful and free outside heat source, an overturned cardboard box would probably work perfectly with no need for insulation or heating pad.

 

[TheGecko]

So I put the small loaf mold outside in the full hot sun with a crystal cake dome over it. I didn't insulate because I had placed it on a hot slab of granite which measured 135F with my infrared thermometer. I figured the crystal dome would act like a greenhouse and an insulator. The single cavity soap I kept uninsulated and uncovered in the air conditioned house as my control sample. I will compare them for ash and color tomorrow. After an hour I peeked and the sun soap was 159F and the single inside soap was 89F by my IF thermometer. After 2 hours the sun soap was 179F. I'm pretty excited!

But you did "insulate it" when you put the crystal cake dome over it. Don't do that...I could go into all the reasons why it's a really bad idea...just take my word from it (I lived in Phoenix for 10 years). Glass, plastic, metal...just don't. A piece of cardboard over the top or a cardboard box would be okay.

As for purple...what shade? Light purple, medium purple, dark purple? Lavender, lilac, plum?

 

[AliOop]

Glass, plastic, metal...

... AND sodium hydroxide, lol

 

[Shirley-D]

Well @AliOop and @TheGecko, I can't pretend I know what I'm doing, just a beginner with flights of fancy. Just something I had to try. I think you are right @TheGecko, the crystal dome was chancy. I considered the dome itself to be the insulation because it is thick, no added insulation. If this works out I will use a cardboard box next time. Anyway, it is 8:30 pm and we just came back from dinner out. I took another peek, looks great! No volcano...no cracks...still warm at 135F. Nothing funny going on apparently so far. @TheGecko, I remembered you lived in Phoenix so I was hoping you would comment.
@AliOop, I put ROE in my bottles of oils, would that help with the possibility of DOS? I will use this soap just for my household and keep a bar in reserve to watch for DOS. I will report back on this thread if DOS appears. Can't wait for tomorrow to see how this turns out. (MUST get a heating pad and act more sensibly)

 

[TheGecko]

Well @AliOop and @TheGecko, I can't pretend I know what I'm doing, just a beginner with flights of fancy. Just something I had to try. I think you are right @TheGecko, the crystal dome was chancy. I considered the dome itself to be the insulation because it is thick, no added insulation. If this works out I will use a cardboard box next time. Anyway, it is 8:30 pm and we just came back from dinner out. I took another peek, looks great! No volcano...no cracks...still warm at 135F. Nothing funny going on apparently so far. @TheGecko, I remembered you lived in Phoenix so I was hoping you would comment.
@AliOop, I put ROE in my bottles of oils, would that help with the possibility of DOS? I will use this soap just for my household and keep a bar in reserve to watch for DOS. I will report back on this thread if DOS appears. Can't wait for tomorrow to see how this turns out. (MUST get a heating pad and act more sensibly)

Insulating your soap is about maintaining the heat a certain heat level which will not only harden your soap faster, but also allow your soap to gel. To accomplish this, folks will wrap the soap in blankets, they will use a heating pad, I’ve seen folks use styrofoam coolers, and of course, an oven.

Some of the reason’s why your cake dome was a bad idea. Glass isn’t porous so you were just ‘baking’ your soap…and your really don’t want to do that. I accidentally forgot to turn off my oven…it was ugly (silicone rash, cracking, some alien brains). It was usable, but don’t sellable and I didn’t need more soap for home. The dome was crystal which will refract (?) the sun, which is creating heat, and can cause hot spots. The glass itself is going to get hot and even though it’s heavy crystal, it’s still a decorative item and not meant for heat like that. And it’s just just the heat, sunlight can be incredibly damaging.

It’s Arizona. It’s freaking hot. Glass, plastic, metal…it’s all a bad idea. First year I lived there…2nd degree burn on the palm of my right when I went to put my car in gear…stick shift knob had a metal plate. After removing the plate, I bought a steering cover (and dash cover and two sun shields). One day I was really stupid and decided to go check the mail…in August…in the middle of the afternoon…barefoot. I made it six feet down my driveway before my brain screamed that my feet were on fire! Both feet blistered…heel, side, pad, bottom of each toe. Room temp water, tea bags, set out outside, set timer for 10 minutes…sun tea done. Get home from work and realized that you didn’t take the steaks out of the freezer…no problem, stick them on a glass platter outside for 20 minutes and they are ready for seasoning and the grill.

If I were stilling there, I’d have a rack on my back patio…covered with a ceiling fan. I’d make soap first thing in the morning…between 6am-8am, cover the molds with cardboard and leave them until mid afternoon when the sun hit the patio…then I’d bring them in and unmold. If I wanted to wait until after supper to unmold, I’d put them on the workbench in the garage.

 

[KiwiMoose]

I regularly use the sun's warmth to 'CPOP' in summer. I have a few wooden molds with lids which seem to be insulation enough. Alternatively I use the garage ( which, in most NZ homes is not insulated like the rest of the house is, so it's always quite warm). I have a couple of soaps crack on top though - so I do keep an eye on them.

 

[Shirley-D]

Well, it looks like I got away with it. Still, I will not be using the glass dome again! Thanks for the warnings @TheGecko and @AliOop . For certain I will take advantage of the natural heat here in Arizona, but not like yesterday. I thought CPOP was intended to bake the soap a bit, now I see it is to maintain the exothermic heat from the chemicals. (That's right isn't it?) How I wish I could have taken soapmaking lessons, but you know... covid. Virtual doesn't suit me. I have to see, do, feel, and smell to learn. I'm a very hands on type of learner. I think I will try what you said @KiwiMoose and use my hot garage :--)


I am pretty pleased with the appearance of the soap from yesterday. The sun popped bar (rectangle) looks better than the control (round). The color improved from a khaki to a dull slightly purple-grey. Hope it gets better. I read my notes and realize I used only 1/4 tsp of Purple Playhouse. It looked gorgeous at the time so left it at 1/4. Should have used more maybe. These photos don't show the true colors by the way.

 

[TheGecko]

I thought CPOP was intended to bake the soap a bit, now I see it is to maintain the exothermic heat from the chemicals. (That's right isn't it?)

Yes. During the saponification process, soap heats up to xx degrees then starts cooling back down. It starts at the center of the soap and then spreads out from there. Sometimes the heat isn't sufficient to reach the outside of the soap or the outside is much cooler and so you end up with a dark ring in the center of your bar...aka 'partial gel'. Insulting your soap maintains that 'gel' temperature long enough for it to control to spread from the center to the outside.

General rule of thumb for colorants is 1 tea per pound of oils. For that mold, with a 33% Lye Concentration and 5% SuperFat, I use about 13.5 oz of Oils...close enough that I usually add a teaspoon on average just because I'm too lazy to want to dirty more spoons. LOL

 

[Zany_in_CO]

CPOP by sun anyone?

This is sucha nostalgic trip for me! Back in the day, when It got hot out, people would post the many different ways to take advantage of the heat. One thing I remember is putting the batch in the trunk of their cars to process it -- always out of direct sunlight because it causes DOS.

Good for you! Thanks for sharing! I'm lovin' this!

 

[Shirley-D]

HA HA HA! The horse picture @Zany_in_CO! Too funny!
I love animals. Here is one of my dogs learning to wear booties for when we moved to Arizona. Started with 2 booties and worked up to 4. @TheGecko you are right! The pavement can burn! I am surprised my soap didn't burn.

 

[KiwiMoose]

Tip: once i switched to neons I had no problem getting my purple to turn out actual purple.

 

[Zany_in_CO]

Here is one of my dogs learning to wear booties

Awww. What a sweetie!

 

[AliOop]

Handsome doggie

Glad your bars turned out ok. Keep an eye out for DOS due to sunlight exposure. This would normally start appearing in 3-4 weeks at the earliest, but it is unpredictable, so only time will tell if you did indeed get away with it. I'm rootin' for ya!

 

[Shirley-D]

AH HA! Neons! Thanks @KiwiMoose. I had just bought a micro sample pack from Crafters Choice. Looking forward to trying them.
Fingers crossed about the DOS @AliOop. Nothing ventured, nothing gained. I learned some good info with this escapade.

Awww. What a sweetie!

Yes, the sweetest, most loving, most obedient, easy to live with dog we ever had! We have three now: Our own black lab above, one we rescued from a very bad situation, then a friend died last Christmas and wished us to take care of her yellow lab...in the picture with the blue toy. OK folks, don't encourage me to talk dog, I will go all off topic and start rambling.

 

[earlene]

The last 2 weeks I have had a great time dabbling and testing my recipes with mixed results, but mostly good and learning by experience. I used a 1lb mold (1/2 Kilo maybe) and some milk cartons to test small batches :--)

Today there is an excessive heat warning for Arizona. It is supposed to reach 110 F (43 C) and I don't want to turn my oven on. Can you blame me! CPOP by sun anyone? Surely somebody has already done this, but I couldn't find it. After a quick search for CPOP by sun and finding nothing like what I want to do, I decided to go ahead and live dangerously.

I made a small loaf of lavender soap with 40/42 EO and buds sprinkles on top. It is just a test, but if it turns out well I would want the buds on top. There was enough batter remaining for 1 cavity mold soap.

First thing I noticed is it immediately turned a horrible khaki color. I used 1/2 tsp of Purple Playhouse from WSP. I know it is early so I hope the color improves with time. (Is that normal? Anyone know a good purple for CP soap? For another thread maybe?)

So I put the small loaf mold outside in the full hot sun with a crystal cake dome over it. I didn't insulate because I had placed it on a hot slab of granite which measured 135F with my infrared thermometer. I figured the crystal dome would act like a greenhouse and an insulator. The single cavity soap I kept uninsulated and uncovered in the air conditioned house as my control sample. I will compare them for ash and color tomorrow. After an hour I peeked and the sun soap was 159F and the single inside soap was 89F by my IF thermometer. After 2 hours the sun soap was 179F. I'm pretty excited!

I will tune in tomorrow with the final result, can't wait! Hope I don't have a volcano with shattered crystal everywhere. I just slid the dome in away from the edge a bit, just incase.
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View attachment 67157

Yes, I have done that. My son lives in Texas & at the time, he was living in San Antonio, where it gets quite hot & humid in the summer. One summer while visiting, I made a batch of really smelling soap & neither my DIL nor I could stomach the smell of it (lard soap for my brother, something I don't normally use in soap). So I put it outside, fully covered to keep the bugs & leaves off (and UV light as well). It was placed high on top of the stone outdoor oven my son had built for his outdoor cooking, so not only was the sun assisting, the stone was as well. It gelled pretty fast out there. It would have been a problem had I used a high CO recipe, or an accelerating additive (overheating & volcanoing can occur, or at the very least surface cracks.) But the surface wasn't too bad as I recall.

I was a bit concerned with how hot it got, but had no thermometer as I don't really bring that along with me when I travel, in spite to toting lots of other soaping essentials along.

It looks like your set up was very much like mine, except for the inverted crystal cake dome. I would worry more about accidentally dropping the crystal an having it explode into smitherines (been there, done that). I tend to prefer inverted cardboard boxes &/or towels.

How long did you leave it outside?

In my case, it stayed outside overnight to cool down somewhat, then I had to move it to the garage because my DIL & I could still smell the lard & neither of us likes the smell in soap.

I have also simulated CPOP in the trunk of my car. While traveling I have tried a few variations on the theme of encouraging gel.

ETA: PS. I also use windshield and dashboard of my car to sun-dry tomatoes here in the summer (when I grow tomatoes, which I have not done for awhile). Super speeds up the process! Cars are good for all kinds of things besides going places in them.

 

[Shirley-D]

How long did you leave it outside?

@earlene I left it outside all afternoon and night. I planned to bring it in before I went to bed but I forgot about it. We have coatimundis, skunks, racoons, and bob cats here (Tuscon foot hills)so I didn't want a creature to get nosy with it. I think it was beginner's luck that nothing bad happened, just watching for DOS now

 

[KiwiMoose]

@earlene I left it outside all afternoon and night. I planned to bring it in before I went to bed but I forgot about it. We have coatimundis, skunks, racoons, and bob cats here (Tuscon foot hills)so I didn't want a creature to get nosy with it. I think it was beginner's luck that nothing bad happened, just watching for DOS now

Wow - lotsa critters! We have nothing like that here. The odd possum but not so much in urban areas.

 

[geegaboo]

There is a heat wave in France right now, so i decided to make a new bar of soap and use solar CPOP.
I mean, what else can i do?

39C and rising. I'm watching every now and then.