Plastic you can mold in your home for DIY projects

Shapelock 500 gram tub
Shapelock is a plastic that is made moldable with only hot water and is perfect for all kinds of do-it-yourself projects.

I finally got my Shapelock plastic molding beads today and decided to try it out. I’m not associated with Shapelock in any way and I (unfortunately 😉 ) do not get any payment for this mini-review.

For those who don’t know, Shapelock is a polymer (plastic) similar to polypropylene except that it has a very low temperature softening point. The idea is that you heat some water to around 160 degrees F and dump some of the pellets into the water to soften them to a moldable state. After molding, you then allow the plastic to cool and it once again takes-on its hard form. The label likens Shapelock to “modeling clay on steroids” and that’s a pretty good analogy.

Chances are that people reading this site have varying interests in such things as pinball machines, electronics goodies, robotics, and other nerdly, gadgety stuff. I doubt that I need to explain why something like Shapelock is useful for such hobbies, but just imagine being able to mold a custom mount for a bank of LEDs or create a new bracket to test the improvement to your pinball machine you’ve been thinking about. Yeah, that kind of stuff.

Shapelock 500 gram tub
Having a bit of experience with plastics, I knew basically what to expect of Shapelock, so I just ordered the 500 gram container. It was $24.95 plus about $6 for Priority Mail shipping. The also have a “free sample” that you can order and just pay $4.95 for shipping if you’re unsure that it’ll be useful for your purposes.

Now, onto the test…

Shapelock pellets Shapelock pellets
I grabbed a small Pyrex bowl and my trusty Sunbeam Hot Shot Beverage Machine to heat the water (I’m impatient and the Hot Shot takes care of that 😉 )

The Shapelock instructions say not to heat the water to boiling, which the Hot Shot does, but I figured that was more of a safety issue than anything. So, I blasted a coffee mug of water through the Hot Shot and dumped it into the Pyrex bowl, thus promptly cooling the small quantity of water signifiantly right away. Next, I added a few spoonfuls of the Shapelock pellets to the water.

Immediately upon hitting the water, they became slightly sticky and began to clump together. With another minute or two, plus some prodding with a spoon, the pellets were a large, malleable mass in the bottom of the bowl. The individual pellets were still visible, as the plastic does not become totally liquid when heated to these temperatures.

I carefully retrieved the Shapelock blob from the water and drained it over the sink to shed any excess, potentially hot water. The instructions recommend using tongs for this operation, again to prevent anyone from hurting themselves – follow the directions! 🙂

With the blob in my hands, I was able to knead the plastic and the individual beads formed into a more uniform modelling clay like texture. The plastic was very easy to stretch, bend, and mold being much the consistency of Play-doh. I rolled it into a long tube with my fingers and joined it into a circle and fiddled with some shapes. I did not find the Shapelock to be gooey or have any problems with it being overly sticky, although it is highly recommended that you not use other plastic implements to work the material as it may stick.

Once I had a suitable shape (suitable for a mini-review), I left it to cool and harden. It took a couple minutes before the plastic was firm and after about 15 minutes, it was pretty cool and hard to the touch. You can accelerate the cooling process with ice water if desired and I’m sure that pieces of Shapelock with more mass will take longer to cool.

Now, with my folded-ring test object fully cooled, I can say that the Shapelock resin is very strong. As you can see in the photos, I formed a shape that would allow me to attempt to fold the object and it resists quite well. The plastic is hard enough that fingernails won’t do major damage although with lots of pressure, will leave a visible indentation/scratch. For anyone who has worked with high-density polypropylene, this will be very familiar. It’s fairly slippery, ridgid yet flexible prior to breaking, and a milky white color.
Shapelock test widget close-up

The material can be drilled and machined as long as you watch the temperatures. Anything causing too much heat softens the material and will cause sloppy surfaces or gum-up your cutting device. I drilled several small holes in my test piece and all drilled easily, but the material does not cleanly remove from the hole due to it’s slighly rubbery nature. This was not a problem and, for example, a screw could be driven into the holes without any issue, but the hole did not look clean after drilling. Also, without reversing the drill, there was quite a bit of resistance removing the bit, most likely due to the remaining material in the bit flutes. Overall, though, the material is easy to drill.

Overall, I am pleased with this initial experience with the Shapelock. I honestly believe that it will be useful for molding various brackets and gizmos for my pinball machine, slot machine (when I get around to it), radio control airplanes, and many other projects. It is not cheap, but it took a surprisingly little amount to create a blob of useful size. Shapelock is reusable as well, simply requiring a re-heat to soften it and move-on to another project.

However, I cannot recommend this for all projects. Shapelock’s strength is the low-temperature melting point. Shapelocks’ weakness is the low temperature melting point. In other words, simply due to the nature of the material, it obviously cannot be used for anything that generates much heat, such as making a mount for a high-powered motor which generates heat. However, for room-temperature needs, I doubt that there is anything better for the hobbiest who doesn’t want to buy an injection molding machine or pay to have parts machined at the local machine shop.

If this sounds interesting to you, I’d recommend grabbing the free sample or perhaps one of the smaller tubs to try-out. I know that I’ll be using it for all kinds of projects and I expect this 500g tub to give me at least 50 more blobs the size of the one you see in the photo (sorry for the imprecise guess) and that’s if I don’t re-use any of it.

NOTE: It appears that this product is also available under the brand name “Friendly Plastic” so you can keep an eye out for that as well.

Please head-over to the and join the plastics discussion forums to post your questions, ideas, and projects. There is a forum for Shapelock/Friendly Plastic specifically, as well as a forum to post your projects, and several others. I’ll select projects from time-to-time and feature them on the top-level page too! The forums are new, so don’t be shy and if you have ideas to suggest a better structure or anything, use the Contact link.

CLICK HERE to order a discounted tub of Friendly Plastic which is more commonly available if you can’t find Shapelock.

75 thoughts on “Plastic you can mold in your home for DIY projects”

  1. Pingback: Plastic Molding?
  2. awesome!
    I was looking up moldable plastics to make a marvin costume (from hitchhiker’s guide to the galaxy)
    just wondering if this stuff would be suitable, and how much would I need?
    And also what do you suggest for molds for such a project?
    It’d be great if you could e-mail me at

  3. Do you guys know of anywhere that I can get something like this that would be completely transparent? It could even be like a clear water bottle. Do you guys know of anything like that? This article was very helpful and I think I’m going to get some.

  4. I need some advice.

    I always make my own costumes every year at halloween. Last year I made a mask out of a cheap hockey mask as a base, using cast plaster to create the mask. The result was amazing. It had just the right texture, it held it’s shape. It was everything I could ask for… except for the weight.

    Would it be possible to create a mask out of cast plaster and use it as a mold, putting this plastic overtop of the mask? My reasoning is that I want to maintain the same texture that the cast plaster gives me, yet have a lightweight mask.

    Basically, how well does this plastic peel off of a surface if you’re using a mold?

  5. Can this be painted? I’ve be looking for mold-able plastic for a while to make custom costumes. Also what type of glue do you recommend?

    Do you think this plastic would stick to a cardboard mold? Should the mold be covered in cellophane?

    So for my strange questions.

  6. I have been searching for something like this for 3 months!!!!!! Can you give me payment options, costs and your shipping data so that I may try some? Oh, and I think I read earlier, that this product can be spray painted, it that correct………Anxious Vickie Smith

  7. To add my 4 bits, I am hoping this stuff can be used to preform copper sculpture projects just to get an idea of dimension and relationship to other, smaller parts. I assume the softened plastic can be rolled out like pasta dough and otherwise formed to PRN requirements as fine as leaves, etc.? I’d like to use it to specifically discover how many embellishment pieces to expect to need/have on hand when I start the real project. In other words, can the warm plastic be so finely carved you can predict channel-set stones and inlay needs? I was planning on using non-hardening clay for this step, but it sounds like the polymorph plastic is a viable option, esp. with the added feature of being completely recyclable. Yes – no?

  8. Vickie:

    You can just spray with Pam or cover with a small amount of vaseline if you’re not going to reuse the plastic – assuming you’re going to make repeat costume pieces for retail sale. Marian

    You can also accomplish the same thing by pouring some $2.00 acetone (available in the cosmetics section of Wal-Mart) into a metal or glass container and then crumbling up pellet styrofoam, the kind that gets molded around electronics when they’re shipped. The foam will literally melt and then you can mold it as easily as you can the polymorph stuff. The only drawback is that the styro won’t be heat conductive like the polymorph is, but again, if you’re making molds to use repeatedly, you won’t care. Of course, once you’ve melted the styro and it hardens, you can always remelt it the same way all over again. Marian

  9. Thanks for the detailed information, Marian!

    The acetone + styrofoam trick is neat, but anyone doing this should be *very* careful as the acetone presents health and flammability issues. Definitely be careful and use protective gear just to be safe.

  10. Hi!
    I am interested in this product for a reasearch engineering project. I live in the uk and would like about 2kilo of the stuff, would you be kind enough and pass my contact to your supplier?.. thank you. I would like to try it out for myself

  11. I have a costume project that Shapelock can be put to good use for! Thanks for the information! You’ve opened my eyes and the possibility of me getting this complex costume finished! Thank you!

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