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Weatherproof Paper Cement Clay for Outdoor Sculptures

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I’ve been experimenting with two new recipes for weatherproof paper mache clay.

Note: We had a vote, and we’re now calling this new recipe “Paper Cement Clay.” ๐Ÿ™‚

I should have done these experiments way back in 2013, because that’s when Warren Eggleton wrote a guest post for this website. He showed us how he made his giant pots using a version of our paper mache clay recipe, with the addition of Portland cement.

The last time we heard from him, his pots had been outside for six years, in Australia.

Weatherproof Paper Cement Clay for Outdoor Sculptures
  • I recently made a casting of a leaf with this mixture.
  • And I sculpted a garden toad to go on the leaf. The new sculptures will be left in my garden over the winter, to see how well they hold up
  • And there is now an update video, after the garden toad spent most of a Minnesota winter outside. So far, he seems to be doing OK, but it may depend on the climate and the product used to seal it. Be sure to do your own experiments.
Lee Bell's Cement Clay Sculpting Recipe

Our friend Lee Bell developed a sculpting recipe that she uses in her beautiful abstract outdoor sculptures. She recently wrote a book about it, which includes her recipe. You can find her book here.

I made some changes to Warren’s version of weatherproof paper mache, just to make sure every batch comes out exactly the same.

I also created two different recipes. One of them contains all the usual ingredients for paper mache clay, but the flour is replaced with Portland cement.

The second recipe leaves out the drywall joint compound, because it’s hard for some people to find.

I tested both of my new recipes by spreading small samples onto cardboard every 30 minutes, to see how long we could continue to use them before they stiffened up too much.

The mixtures will eventually get hard in the bowl because of the Portland cement, but I was able to continue using them for at least 3 hours, with the room temperature at 76ยฐ F (24.4 C).

Warren told us in his post that it will get stiff faster in warmer weather.

Test pieces for weatherproof paper mache clay recipe with drywall joint compound.

Test pieces for weatherproof paper mache clay recipe with drywall joint compound.

Test pieces for weatherproof paper mache clay recipe without drywall joint compound.

Test pieces for weatherproof paper mache clay recipe without drywall joint compound.

How the two recipes are different after they dry:

Difference in texture with paper mache clay for outdoor sculptures

The texture of the recipe that includes the drywall joint compound is smoother – you can see that in the test piece on the right in the image above. However, for an outdoor sculpture, the difference may be so small that it really doesn’t matter.

Try the recipe that you think you’d prefer, and put your sculpture out in the garden.

After it’s been out there for a few months or a year, please come back and let us know if the rain, snow or sun has caused any noticeable damage.

Weatherproof paper mache clay recipe with drywall joint compound:

Note – be sure to watch the video at the top of the page to see how the ingredients were measured and mixed. If you want to make a larger batch, you may want to mix it with a paint mixer attachment on an electric drill.

Mix together:

  • 1/2 cup drywall joint compound
  • 1/2 cup Elmer’s Glue-All (PVA glue)
  • 1/2 cup damp toilet paper or recycled paper*

Mix until there are no lumps of paper in the mixture. Then add and mix well:

  • 1 cup Portland cement.

*To see how to weigh the damp paper, watch the video on this page, starting at the 3:06 mark. You’ll need to scroll down the page to find the video. If you don’t have a kitchen scale, soak the paper in hot water, then squeeze out most of the water (but not all of it) and use 1/2 cup of the damp paper.

Weatherproof paper mache clay recipe without drywall joint compound:

Mix together:

  • 1/2 cup Elmer’s Glue-All (PVA glue)
  • 1/2 cup damp toilet paper or recycled paper*

Mix until there are no lumps of paper in the mixture. Then add and mix well:

  • 2/3 cup Portland cement.

More experiments needed!

Warren had great luck with his pots outdoors in Australia. But I can’t know if these recipes will work here in Minnesota until I make a sculpture and leave it outside to see how well it does in our crazy weather.

In fact, we all need to consider these experimental recipes until we’ve had a chance to try them ourselves, in our own climate.

If you experiment with one or both of the recipes, please come back after a few months and let us know how they worked! ๐Ÿ™‚

109 thoughts on “Weatherproof Paper Cement Clay for Outdoor Sculptures”

  1. Joni
    I have to make smaller batches because I am a detail freak and I am too slow to use a batch before it starts to harden … SO … I have figured out that I can mix up a big batch of the paper, glue and dry wall compound in the correct proportions and keep it in a big air tight container. Then I just take out a portion the size I need and add cement to the right consistency. OR I can add the corn starch, oil and flour to make paper mache clay … ๐Ÿ™‚

    Reply
  2. bonjour
    2 questions
    je ne trouve pas du ciment Portland un ciment ordinaire peut il etre utilisรฉ

    que veut dire sceller le modele

    Reply
    • I think that Portland cement is ordinary cement. Try what you have available, and see what will work. Your local DIY store should have a suggestion for a spray sealer that will work for your project.

      Reply
  3. Jonni requested ideas for less messy mixing for cent clay I had no idea where and how to connect to any of you hereโ€™s what I do Hope you all will try it use a 1galion zip lock bag Put all the dry ingredients into it Including the paper blended up fine Dump the wet ingredients on top zip it shut knead in the bag works great Next Iโ€™m going to roll in the bag too if I can get back to you Iโ€™ll let you know the method

    Reply
  4. Just found you yesterday, so lots of questions. I am looking for a weatherproof clay that can be used like earthenware (potters) clay without having to be fire cured. With potters clay, you can roll it out into a slab, cut it into shapes and use those smaller slabs to hand mold an object.
    I want to build odd/irregular shaped bird houses ( think of those fancy gingerbread houses you see at Christmas) that will withstand the weather. I’m an engineer and retired mixed media artist working in wood,steel,glass, and clay. I see a lot of applications for cement clay that can be worked in slabs like potters clay.

    Reply
    • Hi Perry. I don’t know if this recipe for paper cement clay will work for that purpose. If you do some experiments with it, we’d love to know how they turned out. I have no expertise in cement myself, so anything you can tell us would be great. I really like the bird house idea. ๐Ÿ™‚

      Reply
  5. Hello!

    I’m not sure if I’m doing something wrong, but whenever I soak the sculpture, I am able to just pull it apart when I take it out of the water (and if I scrub it, it wash away some of the sculpture, too). I let it cure for four days; is that just not long enough? It looked dry (like in the video) and I even put it in a heated drying box. It is also somewhat easy to break the dried clay without even putting it in water.
    I made quadruple sure that I used exactly the same ingredients as you (same cement, too) and used the weighing method for the paper.

    Thank you for any advice!

    Reply
    • How big is the piece that you’re making, and how thick is it? If it’s thicker than mine, it would take a lot longer to dry. That’s the only thing I can think of – that maybe it just didn’t have a chance to get dry and cure all the way through. I hope someone else has a better explanation for us. You might try asking on the Daily Sculptors page, too – maybe more people would see your comment, and someone might know what went wrong.

      Reply
    • A note of caution regarding Portland Cements..Here, in Australia…the description for the right stuff is Portland Cement GP (‘General Purpose’) a similar cement is described as “Builders Cement” this has fly ash Pozzolan substituted for part of the Portland. The result is a far slower cure, so is useless in this particular application. Check twice that you are buying Portland Cement GP! Of further note, I’ve found that “Ivory White” Portland cement, (apart from being preferred for pigment tinting), also exhibits a faster set than grey (American gray) Portland Cement.
      There are products specifically created for Portland Cement work…Since the 50’s Australia has Bondcrete (A Modified PVA for external work) and from the same people Silasec (A water proofing accelerant for Portland Cement). Portland Cement is caustic when originally mixed. So’ If trialing fibres to produce composites, note that standard glass roving staples for fibreglass will weaken in a PortCement Mix (Saint-Gobain stock a short glass fibre staple that lives happily with PortCement, another fibre that works with PortCementComposite is Hemp Fibre.

      Reply

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