DIY Halloween Pumpkin – Made with Plaster Cloth and Grout or Mortar

This is a reader-supported site. When you buy through links on this site, I may earn an affiliate commission. Thanks for your support! :)

This DIY Waterproof Halloween Pumpkin is another one of my experiments.

This time, I’m trying to find a way to make lightweight weatherproof sculptures that can stay outside for long periods of time. In fact, much longer than just the Halloween season. In the next three weeks we’ll see if this combination of products has any promise for permanent yard sculptures.

Spoiler Alert: The experiment appeared to be working well, so I used these same methods to create a Garden Gnome. He’s now been sitting outside through two Minnesota winters, and he still looks great.

Edit 6/24/23 – after four years outside the gnome is starting to see some cracking and delaminating between the grout and plaster cloth. There is now a new recipe that we’re calling Paper Cement Clay, and it seems to be holding up well, but we’ve only had one winter to test it so far. If you’d like to see the experiment, and follow links to some projects using it, click here.

DIY plaster cloth pumpkin.
DIY plaster cloth pumpkin.

Because the pumpkin was an experiment, I didn’t spend a lot of time designing this pumpkin’s face, but he’s goofy and happy – and I think the neighbor’s kids will like him.

So – why not use paper mache clay? My own experiences with trying to waterproof paper mache have not been successful. And two people who are really into designing outdoor Halloween decor, Rick from the Ghoulish Cop Youtube Channel and Jay from the Unhinged Productions both agree that paper mache clay will soften if it’s rained on, no matter what coating you put over it.

That’s OK if you only keep it outside for a few weeks, for the Halloween season, for instance, and then bring it back inside to dry off again. But most of us don’t want to lug our permanent yard art in and out all the time.

We do have several guest posts on this blog with ideas for weatherproofing paper mache – (just put ‘weatherproof in the search bar to find them) – but we also get reports from people who say those methods don’t work for everyone.

So – it’s time for some experiments.

If you’d like to watch the Hollywood Haunter’s video that inspired this particular experiment, click here.

If you’d like to watch the Unhinged Productions video that talks about keeping paper mache clay sculptures outside, click here.

If you’d like to experiment, too, and make this DIY Halloween Pumpkin, you’ll need:

Step 1: The plastic bags.

Make a pumpkin shape with plastic bags.

Fill a plastic bag with more bags (or anything that’s soft). Tie off the top. Then use twine to create the dips in the sides of your pumpkin.

Step 2: Cover the bag and twine with masking tape.

Cover the plastic pumpkin form with masking tape.

Plaster cloth won’t stick to plastic bags, so cover the twine and plastic with masking tape.

Don’t leave the twine end inside of the stem, like I did. That made it hard to get the plastic bags out when the plaster cloth was hard. Tape the twine end and plastic bag ends down tight against the top of the pumpkin. Then make a stem with aluminum foil and attach it with hot glue.

Step 3: Draw a face on your Halloween pumpkin.

Draw a face on your Halloween pumpkin.

Use a marker to draw the face onto the masking tape. You can find some great ideas for a face on YouTube and online. Or just draw a happy face, like I did.

Step 4: Outline the pumpkin’s features with foil.

Use foil to outline the features on your Halloween pumpkin.

Use hot glue to attache thin rolls of foil to the outside edges of the features you’ve drawn on your pumpkin.

Cover the foil with masking tape. I didn’t do that. I should have, because plaster cloth doesn’t stick to foil.

Important: Remember to draw a hole for the bottom of the pumpkin. You’ll need it to get the plastic bags out, and to put the LED light inside.

Step 5: Cover the pumpkin with plaster cloth.

Cover the pumpkin with plaster cloth.

I used one roll of 6″ plaster cloth. Cut the roll into smaller sections first, and make sure to keep the pieces away from the bowl of water. They need to stay dry until it’s time to use them.

Use a large bowl of slightly warm water. Dip the plaster cloth into the bowl, allow the extra water to drain out, and then put them over your pumpkin.

Be sure to keep the holes open so you won’t have to do a lot of cutting later.

Important: When you’re finished, throw the water out onto the yard, not in your sink. Plaster will harden under water, and plug up your plumbing pipes.

Step 6: Clean up the edges.

Clean up the edges on your plaster cloth pumpkin.

I used a box cutter and my fingers to smooth the edges of the mouth, nose, eyes, and bottom hole on the pumpkin.

Step 7: Mix your hard coat.

Mix the grout or mortar for the hard coat.

Use the proportions of powder and water that are listed on the bag of your grout or mortar. The instructions probably tell you to use a mechanical mixer. I only used a very small amount, and the stick worked OK.

Step 8: Apply the hard coat.

Spread the hard coat over the plaster cloth pumpkin.

Use a cheap chip brush to cover the plaster cloth with a layer of your hard coat. I used two coats on the outside, and one on the inside.

Step 9: Spay the hard coat with clear varnish

Seal the hard coat with spray varnish.

Use any brand of clear coat spray to seal the inside and outside of the pumpkin.

Step 10: Paint the pumpkin.

Paint the plaster cloth pumpkin.

I used spray paint for my pumpkin. The inside is black, and the outside was sprayed with “Spiced Amber.”

Painting the DIY Halloween pumpkin.

I didn’t spend a lot of time trying to make my pumpkin look realistic, but I did add some light brown acrylic paint to the stem, and some white acrylic paint to the teeth and some reflection lights on the sides of the eyes.

When the acrylic paint is dry, spray again with the clear coat.

Step 11: Add the pumpkin light.

Put an LED pumpkin light inside the plaster cloth pumpkin.

I put my pumpkin light inside a pint-sized wide-mouth canning jar to keep it from getting rained on. Water will go through the pumpkin’s eyes and nose, and we don’t want the light to get wet. You may find a more elegant way to protect your light.

When it’s turned on, your new Halloween pumpkin will look something like this:

Pumpkin with LED pumpkin light inside.

17 thoughts on “DIY Halloween Pumpkin – Made with Plaster Cloth and Grout or Mortar”

  1. How many layers did your roll of plaster cloth end up giving you on your pumpkin? I’m two layers in on a bunny and still find it a little weak for my liking. Your experiments are so wonderful. Even the fails teach us something and I love that you share them since it’s probably pretty tempting to hide them in the bottom of the trash bin.

  2. Jonni, I love your pumpkin. I think part of it being quirky is because it is simple and captivating. What a great Halloween decoration.

    After making around 50 pumpkins, and fighting the square bottom of the plastic bags, I began (1) tying a knot in the top of the bag, (2) cutting off the “square” bottom, (3) turning the bag inside out, so the plastic is inside, not in the stem, and (4) gathering the cut bottom into the stem at the top and wrapping it with masking tape. Next, like you did, was adding the string.

    I love the pumpkin and I hope it weathers the storms. Thanks for your eternal experimenting and pushing me outside of my limits!

  3. Great project! It really turned out well and I like the brush marks and not super smooth because it mimics the ridges on a real pumpkin. This is certainly much cheaper than using something like Pal Tiya, isn’t it? I wonder if the same technique could be used with a paper mache sculpture in order to get it waterproof? Perhaps the paper would absorb too much of the water of the mortar and it would shrink or crack. It also might be sort of redundant to do paper mache and then mortar. Just thinking out loud. Thanks for sharing. I will be interested to see how it fares in the weather.

    • Hi Eileen. Plaster is even more absorbent than paper, so I don’t think that would be an issue. Since paper mache absorbs water, and the mortar or grout stuff doesn’t, I think it might be a good combination. I have a lot of the grout left, and I might use paper mache clay covered with grout on my next project. My only worry is that we won’t be able to tell if water is getting in and making the paper mache clay wet. Can you think of a good (and easy) way to test it?

      Using the mortar as a top coat is a lot cheaper than sculpting with Pal Tiya, but mostly because of the shipping costs. If the Pal Tiya contains Portland cement, as I assume it does, maybe they’ll eventually sell the mixture without the cement. Then we could buy the heavy material at the local DIY store and save a lot of money. That’s how the TruPac X mortar mix is sold. (I’m sure it isn’t as good as Pal Tiya, but I like the way it’s sold.)

      So far, my pumpkin is holding up well. But it’s still early days. :)

      • Heh – I just scrolled down the page where they sell that TruPac product and scrolled through the image gallery. # 17 is a braying donkey. So maybe their product can be used for more than fake rocks.

      • Jonni, how about weighing the pumpkin once is finished and ready to go outside and then weighing it again just after exposure to the elements? The difference (if any) would be a sure indicator that water/moisture penetration had, indeed, taken place.

        • That’s a brilliant idea! It’s too late now for the pumpkin, because he’s been outside in the rain – but I have another project in mind. I’ll definitely try it. Thanks!

  4. I love his silly smile. For permanent outdoor objects, how about trying cement dipped cloth. I make little cement planters using a fuzzy synthetic fabric (will not rot fast like cotton) dipped in cement mix (portland cement and water mixed to the consistency of pudding). You can cut the fabric in strips to use over your taped project. For large projects put on more than one layer of cement cloth. You can also use Rapid Set Cement All Multi-Purpose Construction Material for a stronger faster setting cement mix. I keep the finished project in a bucket of water for seven days to allow the cement to harden better. Then let dry and paint.

      • Jonni, I have not made any sculptures, just plant pots, and little water garden ponds so far. Check out Made by Barb’s website for more info about working with cement this way. I learned a lot from her site. http://www.madebybarb.com/

        The attached image is of one of my little Bonsai trees in handmade cement/fabric planter I made.

            • Wow – that’s nice. I’d love to make something like that, but I’m sure my cat would find a way to make me regret it. It sure looks nice, though. Thanks for showing it to us.

            • I thought the first pot was perfect. This second one has me quite jealous with envy. I used to have a koi pond with plants in it, and I miss it very much. This is beautiful. What a wonderful thing to have created. Thanks so much.

Leave a Comment