Make Doorstop Out of ShapeCrete




Introduction: Make Doorstop Out of ShapeCrete

About: Founding board member of theMakerStation, a new makerspace in Marietta, GA

Our local makerspace, the Maker Station in Marietta Georgia, recently participated in an Instructables build night for ShapeCrete moldable concrete supplied by Cheng Concrete.

ShapeCrete has an awesome projects website with tons of inspiring ideas. I liked this doorstop idea but though it would be more fitting to make one of the letters M-A-K-E for our makerspace. I decided to make one based on the ShapeCrete tutorial:

Step 1: Prepare the Mold

1. Used some super thick roofing foam block insulation that had been found discarded behind our makerspace"
2. It was at least 4 inches thick
3. I forgot to take a picture but I basically drew out the block letters on the foam board with a Sharpie marker by hand.
4. ShapeCrete recommends using 2 inch foam block insulation and printing out the letters with a printer to make a stencil
5. After marking out the letters M-a-k-e and making sure that they all touched, I started to carve them out using a dry wall saw to cut through the thick foam. I didn't get pics of this either
6. After cutting, I put the mold face down on a piece of scrap oriented strand board (cheap plywood) and then used hot glue to secure it to the board and also to add the "holes" for the letters "a" & "e". Again no pics of this step

Step 2: Prepare the ShapeCrete Mix

  1. We neglected reading the instructions on the Shapecrete bucket and simply started adding water to some of the powder mix
  2. If the mix seemed to watery/runny, we simply added more powder
  3. We used an old discarded egg beater and stick to mix it all up
  4. The egg beater worked great

Step 3: Pour the ShapeCrete Mix Into the Mold and Then Let It Cure

  1. Didn't get any action shots but this is what it looked like after pouring the mix
  2. I used a flat stick to trowel it and make sure concrete was pushed into every nook and cranny of the mold
  3. After cleaning up, we let this sit in the mold for about a week due to other activities

Step 4: Remove the Mold and Sand It Down

  1. Pretty much destroyed the mold getting it off the casting
  2. Once again I used the drywall saw to cut the foam insulation mold off
  3. This step was too messy for photos
  4. After removing all of the insulation, I used sand paper to get the remaining bits of foam off and do general smoothing to the edges
  5. I started with coarse 60 grit sand paper and absolutely destroyed it in the process
  6. I followed up with 150 grit fine sand paper to finish it off
  7. I then used a broom to dust it off, followed by an air compressor to get it really clean

Step 5: Paint

  1. Last step was to apply some paint
  2. I used spray paint found in a bin at our space
  3. It had to be red

Thanks Instructables and Cheng Concrete for supporting these Maker Space Build Nites! I would have never done a project like this with their support.


If you are in the Atlanta area, come check out our makerspace in Marietta.

Details at:

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    6 years ago

    Almost $30 (NOT including shipping) for a small 20 lb bucket... that's some expensive concrete! Pharmaceutical grade? lmao


    Reply 6 years ago on Introduction

    As per the comment from ShapeCrete, we did have this batch donated to us. It's been a while since I have used regular concrete but this stuff did seem better and easier to work with, and possibly less toxic... we wore gloves but it didn't seem to have any/as much lime in it. No one complained of any dryness or burns. We were able to use this indoors and clean up pretty easily afterwards.

    It's not available yet at my local HomeDepot, but I think it would be well worth the $20 a bucket for small-medium sized artisanal projects.


    Reply 6 years ago on Introduction

    Fair enough... thanks for the input, and your instructable! :-)

    ShapeCrete Mix
    ShapeCrete Mix

    Reply 6 years ago on Introduction

    Hey Jason,

    ShapeCrete retails for $20 at Home Depot, but we've donated over 3000 lbs. of mix to maker spaces around the country for the Instructables Build Nights, so a lot of people, like the author, got to play with it for free ;)

    Unlike regular concrete, this is a finer mix that can be hand packed into forms, like working with clay. You can make projects with ShapeCrete that just wouldn't be possible with other concrete mixes. It reaches a higher compressive strength than ordinary sacked concrete and can be taken out of the form the next day (instead of a week). Obviously not pharmaceutical grade, but it is way more versatile than anything else you'll find on the shelf.

    Tanju-B, Great job. I like how you used the old egg beater. You should enter this project in the Concrete and Casting Contest if you haven't already!


    6 years ago

    That looks quite cool!