Amanda, of Lovin Soap was so generous to allow a "reprint" of her DIY Reusable Liners for Slab Mold article. If you want to go to read it from her blog, it is listed under "Tangy Tutorials (love that!) This is that tutorial:
I went to my local plastic supplier, Allied Plastic Supply, and bought a big stack of lexan (polycarbonate) sheets for 15 bucks. When looking for lexan locally check out your local sign shops, sign shop suppliers and plastic suppliers. It’s a really cheap material and works great for lining molds. You can buy it in large sheets if you have a big mold. If you can’t find lexan you can also use the thin plastic chopping mats (for cooking!). Just make sure that whatever you find has a smooth side. This will be the inside of your mold. Also make sure that whatever material you choose is thin enough that you can still get your dividers back into the mold when lined.
Measure your mold and cut out a bottom piece and 4 side pieces.
If your material has a smooth side and a rough side…place the pieces with the smooth side down. Tape all four seams. You can use clear tape, painter’s tape, masking tape…really any kind of tape you want.
You’ll need to leave a tiny amount of space between the pieces for when you fold the sides up. So don’t tape them butted up touching each other. To test to make sure you left enough space tape one seam. Flip it over and fold up the outer piece towards the inside to make sure it folds up okay. If so…flip back over and finish the rest of the seams.
Once you tape all of the seams flip it over (shiny side is now up- this is the inside of your mold) and tape the sides along the seam on the outside.
After you tape all of the seams place your liner into your mold and make sure your measurements were correct and it fits!
It fits! Whew!
Also insert the dividers just to make sure the material you chose for the liner isn’t too thick. Everything fits nicely!
Time to make soap! It looks unlined…but the liner is in there!
Ta-da! If it comes untaped (mine did) no biggie. You might have to untape it to clean it anyways.
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