Using PVC as a soap mold

[bonnyny]

I did the same as Shirley, and sawed the 3" diameter pvc in half, making it 12" high. Each one will make eight 1 .25" - 1.50" slices. Many people have commented that they like how the round shape fits and feels in their hand.

 

[DeeAnna]

When I first started soaping in '04 all the soapers were using pvc piping. I'm surprised there are soapers who still use it. It's such a headache. I tried it once because I was new at soaping and experienced soapers suggested it. But it only took one attempt to make me hate it. There are better and and more versatile options.

Could you discuss those "better and more versatile options" that you've discovered?

 

[Belindasuds]

I still line my PVC pipe with freezer paper. I like to think the freezer paper protects the soap per se. A dab of Vaseline on the pipe holds the paper pretty good too. The caps seal them nicely on the bottom with saran wrap inside as well. I love my round Soaps!

I second this!
I use the same approach as Noreen, especially if I'm not heating to force gel.
If I am heating my soaps to force gel though, I usually skip lining the mold as I find that when I gel soap it releases easily. Discovered this when I accidentally forgot to line the mold and was both relieved and pleasantly surprised when it came out easily.

Pringle cans are great for single use. I like that I can cut them in half to use for smaller test batches. The lids work well as end caps to prevent spillage, but I always place the mold in a bowl before pouring just to be on the safe side.

 

[CatahoulaBubble]

A good liner to use with PVC is a food grade plastic cutting board. One of the flexible ones. You can cut it to fit inside the mold perfectly where it caps but you can leave the top longer so that you can push out the soap by removing the cap and putting that end up while using a counter or table to push the plastic liner through the pipe enough for you to get a grip on it and then pull it out the rest of the way. Then the cutting board plastic just peels off.

 

[GGMA0317]

Plastic Mailing Tubes.
The ones I use are measured at 18X3 and 18X2. However, they can be purchased at a longer length.

The best way to use them is to simply cap the bottom only and use the 18 inch freezer paper that is naturally coiled and fit perfectly inside. I've NEVER had a problem removing the soap as it pushes straight through. Ok, once there was a little bit of soap that rose slightly up the middle but it wasn't a big issue.

I make braces with sturdy cardboard boxes. I measure the round holes and cut out circles in the box and I place it on the floor and put my prepared molds in the box and pour my soap. I've also braced them in a sink.

I got my tubes from Uline.
I was determined to have round soap so I searched every possible option. The 2 inch rounds are so perfect for guests and gifts. You can even swirl a bit. I don't work with colors anymore. But years ago I did and was able to swirl in the tube.

Also, I probably don't have to say THIS- Do Not Cap The Top Of
The Tube! Be sure to put your tube wherever its going to stay after filling. You do not want to carry these filled with raw soap.

Ok. Now go yea therefore a tell everyone to toss out those horrid pipes!
HAPPY EASTER AND HAPPY EASY ROUND SOAP MAKING!

Plastic Mailing Tubes.
The ones I use are measured at 18X3 and 18X2. However, they can be purchased at a longer length.

The best way to use them is to simply cap the bottom only and use the 18 inch freezer paper that is naturally coiled and fit perfectly inside. I've NEVER had a problem removing the soap as it pushes straight through. Ok, once there was a little bit of soap that rose slightly up the middle but it wasn't a big issue.

I make braces with sturdy cardboard boxes. I measure the round holes and cut out circles in the box and I place it on the floor and put my prepared molds in the box and pour my soap. I've also braced them in a sink.

I got my tubes from Uline.
I was determined to have round soap so I searched every possible option. The 2 inch rounds are so perfect for guests and gifts. You can even swirl a bit. I don't work with colors anymore. But years ago I did and was able to swirl in the tube.

Also, I probably don't have to say THIS- Do Not Cap The Top Of
The Tube! Be sure to put your tube wherever its going to stay after filling. You do not want to carry these filled with raw soap.

Ok. Now go yea therefore a tell everyone to toss out those horrid pipes!
HAPPY EASTER AND HAPPY EASY ROUND SOAP MAKING!

Excuse my horrible photos and this soap is 2 years old castle oatmeal and gm.

 

[RandomSoapMaker]

I have been using the PVC pipes (18" long) and use the hot process. After filling in the pipes at around 145F-150F and tapping them out, (and also compacting it down with a smaller pvc pipe with end cap) I normally leave them up against the wall with no covering.

The problem is the inconsistency in yield. In almost all batches there is some tunneling or air bubbles in the top 80% of the fill, and in about 10% of the batches there is tunneling (air pockets of empty cavities) upto 50% of the batch from the top. Is there a mini volcano happening in there? Anybody having any issues like this? Or are the sugars acting up? Have tried different recipes but the tunneling is consistent...

 

[Nibiru2020]

PVC works great for round soap molds. You'll want to make sure that the inside is clean and free of burrs so that you don't get a gouge down the side of your soap when you demold.

PVC caps like you buy at Lowe's, HD, and the like are rounded, so unless you build a frame for the pipes to sit down in they're going to tip over.

You can buy a 3" PVC floor flange at Lowes or Home Depot for around $4. The pipe fits inside and all it is flat on the bottom, plus since it's a flange it has ample support to stand the pipe upright without worries of it tipping over, plus you can remove it to slip out the soap after it's cured.

This is shown as the bottom facing up, so you can see how sturdy a support this would be. This appears to be the simplest, easiest fix IMHO.

 

[AliOop]

@RandomSoapMaker I always had some tunneling in my 3" PVC molds when I poured in HP batter, as well. It doesn't happen with my CP batter, but I will say that my CP batter gels in those molds without any insulation whatsoever. So I think the thick PVC itself acts as insulation and heats up the batter even further.

@Nibiru2020 does the flange seal the bottom of the pipe well enough to prevent leaks? I've been using a tester cap, which has a great seal, but with the wing-nut on the bottom, requires a wooden stand to hold it upright (which my husband was sweet enough to build when he cut the pipes for me). It would be great to find a flat solution as long as it doesn't allow the soap to leak out. I do CP most often now, so the batter is quite a bit thinner than HP and more prone to leakage.

 

[The_Phoenix]

Plastic Mailing Tubes.
The ones I use are measured at 18X3 and 18X2. However, they can be purchased at a longer length.

These? Plastic Tubes, Clear Plastic Tubes with Caps in Stock - ULINE

I loathe using PVC tubes. I'm open to alternatives.

 

[DeeAnna]

GGMA hasn't been here since last September. Yes, those are the tubes they used. I pointed out to this person that these tubes are PETG, which rapidly becomes brittle when exposed to strong alkali. But apparently they use the tubes without any problems, so YMMV.

The caps are PVC which is chemically resistant to alkali, but PVC will soften at temps above 150 F / 65 C, so use caution if you also use these caps. CPOP wouldn't be a good idea, for example.

 

[Nibiru2020]

@RandomSoapMaker I always had some tunneling in my 3" PVC molds when I poured in HP batter, as well. It doesn't happen with my CP batter, but I will say that my CP batter gels in those molds without any insulation whatsoever. So I think the thick PVC itself acts as insulation and heats up the batter even further.

@Nibiru2020 does the flange seal the bottom of the pipe well enough to prevent leaks? I've been using a tester cap, which has a great seal, but with the wing-nut on the bottom, requires a wooden stand to hold it upright (which my husband was sweet enough to build when he cut the pipes for me). It would be great to find a flat solution as long as it doesn't allow the soap to leak out. I do CP most often now, so the batter is quite a bit thinner than HP and more prone to leakage.

Yes it does seal well. The heavy viscosity of the soap mixture will not leak through at all. I have seen some folks use a bit of tape around the joint to ensure a good seal, but it's not really necessary. Water or thin liquids might leak but with the viscosity of soap there should be no issues at all.

 

[PaintyLiz]

I haven't used the rounded ones yet, but I do use PVC downspout which is made of the same thing, just shaped like a downspout (duh - bet you didn't guess that LOL). Anyway, I don't grease it. And there is no cap for that shape so I would think that you could just cover the round one the same way I cover mine if you have a hard time finding a cap in your area. Around here you can only find them at plumbing supply warehouses. I take a piece of cheap plastic wrap about 8x8 or so and fold it in quarters so it is 4-ply. I place it across the bottom and then use duct tape to tape it up really well going in both directions (across and up and down). Just make sure that the tape is sticking to the PVC and not only the plastic. I just cover the top with a couple of pieces of duct tape and that's good enough. I also make sure it's at a pretty thick trace before I pour so that it's less likely to leak out. I place my mold between my oven and fridge and it insulates it perfectly. Mine stands up on it's own as long as no one bumps it - but otherwise I would wedge it up against a wall and place a cinder block against it. I bought one at Home Depot for cheap just for that purpose. It beats building some fancy thing for it to stand up in.

Lastly - you need to unmold them as soon as you can stick your finger in the top and it's firm. Don't let it go too long or it will be impossible to get out. Freeze it for 2 or so hours and then run hot water all around the sides of it - make sure one end is uncovered. Sometimes the heat and condensation makes it just slide out all on its own. Otherwise, make something with a rounded end (maybe a juice can or something) and put a piece of wood or something hard inside and push it out. If it's REALLY stubborn and is getting squished, let it sit a little longer and let condensation build inside. Once it's out, I usually let it sit about 24 hours on my counter and dry up a bit before I slice it. Voila! Beautiful bars.

SIDE NOTE: If it was frozen all the way through, you will HAVE TO make sure you give it a day before you cut it - even if it seems firm enough. I made the mistake of thinking it was firm, but really it was frozen and each bar cracked as I cut it. Smelled good though! LOL

I joined the forum just to tell you how much I appreciate your post! What a great idea! I have a piece of really neat plastic gutter downspout laying around that would make a great mold! Thanks for the idea & instructions!