Making Round Soap in Poly Tubing

If you’ve ever been frustrated at trying to get your round soap out of a PVC pipe, you might want to check this out. The idea has been floating around the soap blogs and forums for awhile now. Of course I heard about it right after I had just invested about $50 in a custom sized 2.5″ PVC pipe (the plumbing store would only sell me a full-sized stick), so I wasn’t overly anxious to go out and purchase more supplies.

Ok, so I got a little bit frustrated with the pipe. Even freezing the soap in the pipe, then pulling it out and letting it sweat wasn’t working every time. So two months ago I invested another $32.61 in some 2.5″ poly tubing. Hello. A 2.5″ flat tube is totally different from a 2.5″ round tube. Unable to send it back without incurring shipping fees plus a 25% re-stocking fee, I still have it. I let it sit there staring at me for about a month before I decided to go ahead and order the correct size – which was 4″ tubing. (Yes, 4″ flat tubing will give you about 2.5″ diameter soap.) And then life got busy.

Yesterday, I finally got around to making my Beer & Seaweed Shampoo Bars in the poly tubing. Hubby helped me with the set-up. I needed a way to prop the bag up and open while I poured the soap in.

Pipe fittings to hold the poly tubing, with a hole in the end of a board
The board goes all the way to the back of my supply rack, with a box half full of business cards sitting on top.

I had to stand on a chair to get to the top of the tube and pour the soap in! Also folded over a bath towel and placed it on the floor under the tube to catch any drips.

I taped the funnel to the top of the pipe fittings

I left the soap hanging there overnight. It was actually ready to cut about 18 hours after I poured. The tubing slid right off – success!!

Here are the cut bars:

Deep Patchouli Beer & Seaweed Shampoo Bars

Here are some of the differences that I’ve noticed between this batch and previous batches:

1. They definitely did NOT gel.
2. They have more air bubbles from pouring such a long way down.
3. They are exactly 2.5″ in diameter which is slightly larger than the ones I made in the pipe – pre-cure weight is at least half an ounce more.
4. I’m also short a full bar – partly due to the knot at the bottom of the tube, and partly due to the slightly larger diameter, but I can deal with that!
5. This was SO much easier! I have a batch of the Lemongrass Herbal Mint already poured this morning. This is definitely going to be the way to go for these soaps!

Here is what they normally look like:

Beer & Seaweed Shampoo Bars

Check out the updated tutorial for using poly tubing HERE.

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  1. Very cool Amy your set up is industrial! LOL! I shared this idea and plastic tubing bags with Emily ways back. I used an orange juice can with bottom and top cut out oh and hubbies hands! Em used a vase! You might use the 2 1/2 ” plastic for embeds?? Can’t wait to hear! This fragrance sounds yumma!

  2. Nice set up! I use bags but inside a cardboard shipping tube. Not very long. Your system is much more efficient. Bubbles are an issue I have with my other vertical mold, too. Maybe try to pour along the inside of the bag? And have you considered making guest size soaps with the 2.5″ diameter bags?

  3. I’ve considered embeds for the smaller bags…just haven’t done it yet. I pulled it out for the landscape challenge, thinking I would make the sun out of it, but it’s too large for that. Love the soap just posted today by A Life Deliberate. So pretty!!

  4. Just found your blog and very new to soap making. I mostly want it for our household. I plan to use some frozen juice cans for my next batch. Have you tried those yet?

  5. @Julie – I have not. You will either need to use the plastic kind, or remove the aluminum bottom before adding soap. Lye and aluminum don’t mix!

  6. Interesting. Are the soaps pretty uniform in shape? I am definitely annoyed with the tubes and need a new option.

  7. @Erica – Besides the knot in the bottom, and the one at the top that isn’t quite as round, they seem to be pretty uniform. I would go for it if I were you!!

  8. I made soap rounds in a 2.5 inch PVC Pipe and found that I could only get them out by freezing and then running under HOT water for a minute. Then they came right out, but I lost some in the transfer (the end I was pushing get dented and I had to shave some off.)

    Overall I have to say that I didn’t like how they came out. To me, they looked not fancy enough. If I had a soap stamp, then I would’ve liked them much better….Also, they were a touch messier to cut.

    I like the plastic tubing idea! You didn’t have to insulate the bag at all?

  9. @Lindsey – The pipe can be very messy! No, I didn’t insulate. But then the soap didn’t go through gel phase either. Still works, but it will take a bit longer to cure. I put a fan on them to try and speed them up. 🙂

  10. Cool and groovy Miss Amy! As always you are a wealth of info and I so appreciate the time it takes to take photos and post about what you are learning. Bags are now on MY shopping list.

  11. What a great idea!! I have always used PVC pipes, and ended up with tendinitis from the struggle it is to get the bars out… I will definately try it, thank you SO much for sharing this info, I really appreciate your blog and all the great tips you give us less experienced soapmakers… Gracias! Greetings from Chile…

  12. I just bought a mold at the Alabama Soap Meeting that is made with pvc pipe and a valve stem, really neat setup! It wont handle a batch as big as yours, but for me it was just right. If you have a handy person in the family I’m sure it would be easy enough to make for yourself. Here is a link to the vendor

  13. That looks great! I was going to order the 2.5″ PVC, but have not done it yet…I have found the easiest way to get the soap out of the PVC tubes is to heat it up in a pre-heated, 170 deg. oven (mold & all), turn off the gas, leave on the light, for about 20 minutes. Now mind you this is for the 2″ diameter PVC, but it should work fine if you have a good push rod to push the soap out in the larger size tubes. Works perfect every time for us!

  14. My husband and I love your Beer & Seaweed Shampoo Bars! I have got to try and make shampoo bar now. I’ll definately be buying more of yours tho!

  15. Wow Amy, that is a fantastic idea. I avoid making round soaps, because I hate trying to get them out of the tubes.

  16. I LOVE this idea!! I’ve been stalking the plumbing aisle at Lowe’s for a while now, trying to decide exactly what I wanted, and how I was going to make it work. This is DEFINITELY an option! (It’ll save space too! No molds to store!) Now…. to figure out what size is needed for 2″ shaving soaps… 😉

  17. I’m confused about which tubing to buy. Are you sure this is 4″ diameter tubing? How do we get a 2 1/2″ inch soap from 4″ diameter plastic tubing? Did you mean 4′ circumference? Help, please?

  18. I’m looking to do something similar to what you did, and the link you provided looks like they only sell 2mil thick bags. The place I’d get them from sells 2, 4 and 6mil thickness polyethylene tubing (I’m in Canada). Do you find the 2 mil strong enough? Or would you try a heavier thickness given the chance?

  19. @Dagny – I’ve only had one mishap with this polytubing, and I believe it was a manufacturing error where the seam was weak. It started bulging at the bottom and I nearly had a disaster! The thickness of the tubing itself doesn’t seem to be an issue though.

  20. Thanks, Amy! A weak seam will cause havoc regardless of the thickness of the plastic, so I might as well save money and get the 2 mil! I’ve already pointed a friend at your site asking if he can help me make this (I should NOT be allowed near any power tools or mechanical construction…I cause more harm than good), and he’s already suggested what are ‘improvements’ in his mind, anyway. I’ll send you picture if you want, once it’s up and running.

  21. I had a question for you… at the temperature that soap heats up to in the gel phase does the plastic tubing shrink or get damaged? what is the guage of that plastic tubing you are using?

  22. @janaki – I haven’t had the tubing shrink or get damaged from gel phase. In fact, unless it’s a recipe that heats or the weather is quite warm, the soap may not gel at all. The tubing is just 2ml thick.

  23. Hi Amy,

    I wanted to update you on my soap making setup. In the end, my friend realized that the holder contraption (the pipe and connecter used as a ‘funnel’) really was the best solution. But, he suggested mounting shelving rails to the wall so I could have adjustable heights. And, since the spacing was 18 inches apart (or so), He was able to drill 3 holes in the board, and they fit perfectly between the two shelving brackets holding it all up.

    I can’t post pictures here, but I put a few on my website for you to see:

    What I like about this set up is that I can pour while standing on the floor if I want and have multiple soaps on the go. When I’m done pouring, I take them downstairs to a cat-free area where I have bakers racks for curing all the soap. One rack is dedicated (so far) to hanging the long tubes for those first 24 hours until they can get cut. Once cut, they go into the wire baskets on the other baker’s rack for their multi-week curing journey.

  24. I’m going to buy that tubing. I don’t like the seem left when using the mold I got
    And I loveeee your shampoo bar <3

  25. Can you tell me how you avoid air bubbles? I am loving using the polytubing but finding it very hard not to get air bubbles.

  26. @Nicola – I use the funnel, and pour very carefully down the side of the funnel and into the polytubing. Your soap batter needs to be pretty thin. Sometimes I tap the side of the tubing after the soap is poured to help it settle.

  27. Hi
    I use this method from about 2-3 years,it’s very confortable.I am glad that ather soapmaker find this a good method.
    Great idea to make it known for athers soap makers

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