How to Pulverize Set Plaster for Re-use




I did this at TechShop Menlo Park.

To save yourself a few dollars, you can re-use old plaster molds to make fresh plaster powder.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Find Cardboard And/or Thin Plastic Sheetss

Dig for whatever you can use to wrap the old plaster chunks and prevent the dust you'll be creating from flying around.

Step 2: Load Plaster Chunks

Load your set plaster pieces into your cardboard or plastic sheets.

Step 3: Make a Wrap

Wrap up plaster chunks into a nice secure wrap.

Step 4: Roll and Smash!

Anything big and heavy will work. I found a huge steal pipe and used it as a rolling pin.

Step 5: Banging Technique

Keep smashing as hard as you can. Watch your toes!

Step 6: Plaster Dust

Open your package to find plaster dust with some chunks. You can repeat steps to get it to its original powder form but you must mix it with fresh plaster mixture for mold making anyways and so the chunkiness won't matter. 
This is a great way to get some anger out while simultaneously creating something useful and saving some money for your future art supplies.

Be the First to Share


    • Book Character Costume Challenge

      Book Character Costume Challenge
    • Made with Math Contest

      Made with Math Contest
    • Cardboard Speed Challenge

      Cardboard Speed Challenge

    11 Discussions

    Jacob Opstad

    1 year ago

    I've reused plaster a few times by scraping it with a scraper that I made from a steel can with lots of small holes punched in it with a really thin nail. It works great for getting it down to a pretty fine powder without all the steps in between.

    Landfill sites refuse drywall and plaster because as it decomposes, hydrogen sulfide gas is released. So, re-use it by crushing it and reheating it in a 325 degree F oven overnight, to drive out the hydrated water.

    2 replies

    Hours and hours. 6 to 8 of them. It's a reminder why cements and plasters are environmentally costly.

    I built a solar oven to do the job. One small batch of plaster at a time, but no energy cost.


    7 years ago on Introduction

    It will also accelerate the set of fresh plaster, which may be convenient or not.


    7 years ago on Introduction

    I have just had a look at your other instructables and I see you have made a furnace for lost wax casting, you might be intrested in what I want the brick grog for, I'm doing an instructable for making your own crucibles might be useful for you ;-)


    7 years ago on Introduction

    further to my earlier comment, I took an old shirt and ripped it so it was square wrapped up some old pieces of garden pot and smashed away with my club hammer and it worked great.

    so the answer is yes this can be used to make your own grog, hard work with a club hammer though, but it works.


    7 years ago on Introduction

    this seems like a good method for making your own grog for ceramics from brick or old garden pots.

    once its all smashed up you could pop it in to a ball mill for a finer powder

    heathbar64Mr. E Meat

    Reply 7 years ago on Introduction

    yes, to make it back into usable plaster you would need to heat it to extreme temperature to drive out all the water, even that chemically bonded to the gypsum. I don't know the temp. What he is doing here is adding it to new plaster, basically as an inert filler.