Here's a link to an article by David Fisher about using a 12" long section of 3" round PVC pipe to make loufa soap. http://candleandsoap.about.com/od/soaprecipes/ss/loofahsoap.htm In the instructions, David says that he uses vegetable cans to push the soap out of the mold. For the batches that are more stubborn about comming out, David says he puts them in the freezer for a while. Then, he can get the soap out.
I have really hurt myself getting soap out of tube molds! I do have a new method for soap release though that might work. Most everyone already pops their soap & soap molds in the freezer, but I have discovered that after you freeze the soap & mold you can hold a hair dryer to the frozen mold to & get the soap super easy. I do this w/ soapsicles but I think it might work w/ the tubes as well. I hacked my tubes away about 3 years ago because I was tired of the fight. I may pull them back out & give em' a try.
Using a hair dryer on the frozen mold sounds like it should work well. As the mold heats and expands, the soap should remains cold and a bit smaller! Kind of like running water over the bottom of an ice tray to get the cubes to pop out easier.
I made the orange looking M&P soap. I bought some PVC at Lowe's. It was very hard to keep the slices of orange where I wanted, but that may have been due to the fact that i made the molds long (24") and filled them lol.
I did smear a thin coat of vasoline inside the tubes and used an empty paper towel cardboard center (all I had around) to push it out, wasn't very hard to remove.
Don't forget the alcohol! It helps keep you entertained while waiting for the soap to harden and oh yeah it keeps those orange slices in the orange once sliced!
The width of the tube is going to make a huge differnec. If you use round PVC pipe the size of your fist it is going to be 10 times easier than those little butterfly or star shaped tubular insert molds.
You can get a very similar look w/o a tube mold making little embeds in shaped ice cube trays or chocolate molds or cutting shapes out with cookie cuters & dropping them into single bars of soap.
I have used PVC pipe and I invested in one "flower" tube mold so far. I really like them. Sometimes it is a b!tch to get the soap out. For some molds I spray a little candle mold release spray, it helps. I'm going to TRY to post a little pic here of the violet soap I made using this tube mold, but not sure if it'll work. I used a straw to hold the soap out of the center and filled the hole with a different colored soap. If I remember correctly, it was difficult getting it out of the tube and the end ended up all smashed but I didn't need the full length to put into the loaf mold, so I lucked out.
I don't spray or line mine. I just let them set for a day and then freeze them for 2-3 hours and then run hot water over them. Then I let them sit for a few minutes and let the condensation build and then push something inside until they come out. Then I let them sit another 12 hours before cutting. Mine have always turned out perfect.