How to Use PVC for Sculpture Armatures

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Today we have a guest post from Clayton Trehal, who mentioned his PVC armatures in a recent Daily Sculptors post. When I asked him about his process, he agreed to write a tutorial for us. Thanks, Clayton!

© Clayton Trehal

Making Sculpture Armatures with PVC

Hi All,
I sent this information to Jonni because her clay recipe and video tutorials has been immensely helpful to me. I shared some information about using PVC for armature material for paper mache sculptures and she suggested I write this up. What follows is a tutorial on how to use PVC irrigation pipes as armature for your sculpture because this material is strong, gives you some choices cardboard and wire doesn’t, and actually quite easy to work with.

Above are two of ‘The Boys’. My son and I are building a few sculptures for fun. Rancor is a creature from the film ‘Return of the Jedi’. The ‘Boys’ you see here are getting close to the place where I’ll finally apply Jonni’s paper mache clay, but I like to use a base of normal mache.

Rancor is made of packing paper, newspaper, cardboard, 2-liter bottles, some wire for hands and tail, all sitting on a PVC skeleton. His dimensions: From foot to top of head/back, Rancor stands nearly 18” tall and about as wide/long.

To understand how PVC is being used here, let’s go backwards a bit:

 Rancor sculpture in progress, with PVC pipe as the base of the armature.

Here is Rancor 3 before his base coat of mache. You can clearly see here his skeletal materials. I knew getting a two-legged creation to stand on his base would be an issue, so I immediately thought of PVC.

I’ve been doing mache for a long time and the longer I do it, the more I realize that what goes under is just as important…maybe more important, than what goes on the top. So that he’ll stand, Rancor is anchored to his wooden base by bolts and nuts that go through his PVC ‘feet’.

Once I have the pose the way I like, everything is glued and he’s really solid. Those bases (particle board and hardboard) are heavy, but you can lift the entire unit by grabbing Rancor. Let me go back a bit further though to show you how to do this:

Sketch for PVC armature for Rancor sculpture.

Please forgive my artwork and writing here. You can see that Rancor’s torso is basically a PVC ‘I’ made of 1 pipe ‘spine’ and 2 T fixtures. His arms and legs are simply links of pipe that are bent at shoulders/hips and elbows/knees (and ankles so that the sculpture fits squarely on his base once I attach the 2 PVC caps I use as feet. I use 2 2-liter bottles here for the basic torso shape. I knew I wanted to use PVC and experimented with many things, but in the end, 2 liters gave me the best form.

Note: I take for granted that you have the tool to cut PVC because I’ve had mine for a million years for sprinkler repairs. In order to cut PVC, you can use a hacksaw (the fine blade one that cuts metal), and that works just fine, you can even use a miter saw (like the electric kind), but the tool that they make for it is called a PVC Cutter. This is basically a specialized clipper designed to cut plastic pipe. They sell these on Amazon or at any Lowe’s/Home Depot.

How to bend the PVC:

How to Use PVC for Sculpture Armatures

Here are the only tools I used to make my PVC skeleton. The Heat Gun here is the cheapest one they sell at Harbor Freight (I think I paid about $20 and I’ve had this guy for years), a pair of gardening gloves (optional…you have to hold the PVC for about 2 minutes while it cools and it’s fairly hot), and PVC glue (this 2 pack is about $15 at Lowe’s). I never made a video of what I did, but this pic kind of shows you:

Using glue with PVC pipe for sculpture armature

If you look at Rancor’s right arm, you’ll see a line where I needed to make the shoulder bend and another line at the elbow. Before you do any bending, you’ll have to determine how long the limbs are and where you plan to joint them.

I used Jonni’s method of making a grid pic of Rancor to determine my dimensions. I also experimented a lot with hands and in the end, aluminum wire taped to cardboard seemed to work best. Anyway, once you have the dimensions, you are ready to bend. BTW: ½” PVC probably would’ve given me the strength I needed, but I like using ¾” and for this sculpture, it works fine.

When ready to bend, put on your gloves and heat the PVC on the joint line for about 2-3
minutes. Make sure to go around the entire pipe (you do this by spinning it in your hand as you heat it.

You’ll know you’re done heating in 2 ways:

  • You’ll start to see the pipe sag (it gets the consistency of a rubber garden hose)
  • and/or you’ll start to notice a browned-marshmallow (like when you’re making Smores) look.

Turn off the heat gun, and pose the PVC to whatever positions you’d like and hold for about 3 minutes. The amazing thing is that when the PVC cools, the joints are actually stronger than the unjointed pipe. It’s as if heating the material tempers it. The T-joins act like joints too. You can move the arms/legs back and forth until you are happy with the angles.

I don’t glue until everything looks the way I like. BTW: I used short/hard bends here, but in other projects, I’ve also used gradual bends, like when I used PVC to make the huge abdomen of a paper mache spider. In those cases, the length of the pipe you heat is bigger…in the case of joints, you only need to heat a 1” part of the PVC. I’m sorry I never made a video, but hopefully the pics show you what to do. The bottom line about PVC…it’s really easy to work with, and it’s also really strong. My statues are 18” high, but you can make something much bigger.

How to Use PVC for Sculpture Armatures

The picture above is the stage before the base coat.

In order to give the Rancor fill, and to hide the PVC and 2-liter bottles, I wrapped him with newspaper. Since I did three of these at once, it enabled me to realize how important the newspaper wrap was. I gradually came to realize that much of the sculpture I was doing (it’s basic shape) was actually done in newspaper, and wrapping is an art unto itself.

So there’s my PVC tutorial.. I’m sure it’s not that great but hopefully the pictures give you the general idea. Hopefully someone like Jonni uses this and makes a good video tutorial.

Again, the advantage of PVC is that it’s strong and actually pretty easy to use. Each Rancor I make is about 4 ft of PVC. It costs $6 or so for a 10’ length of PVC, and each T fitting is about 72 cents. The foot caps are about 80 cents each, the glue is $15 but you can use for multiple projects. A heat gun is about $20 for the cheap models and can go up to $100, but my cheapie is literally decades old.

I hope this tutorial is helpful, and I’ll share some finished pics when I get there. I LOVE the effect of the clay and how it feels. It’s really hard for me to be patient and not go right to it. Jonni, thanks again for your helpful videos, mache recipes, and your overall creativity and cleverness. I’ve learned a lot and hope that this tutorial may be helpful to someone.

Clayton Trehal

8 thoughts on “How to Use PVC for Sculpture Armatures”

  1. Hello Clayton, thank a lot for your time and explanations in this tutorial, really interesting. I did use pvc but never realize I could bend it to position it right. That’s is new to me as I don’t have a heat gun. I was searching into welding but pvc look like match more easier! Thanks!

  2. This is wonderful! Thanks for sharing it! I’ve used pvc in my sculptures before for outdoors when I don’t want them to blow over in the wind. These are not paper mache sculptures. I usually slide the pvc embedded inside over a piece of rebar, but it’s wonderful to think of using them as a skeleton. Does the PVC give off toxic fumes when heated? Should this be done outdoors? I guess 45 degree couplings would be more restrictive than your pipe heating and bending accomplished. Thanks again for the info.

    • Sharon, as far as I know, the PVC doesn’t give off fumes, but I always open the garage door when I do it. The first time I did this, I used both 90 and 45 degree couplings, but as you say here, they were more restrictive. The benefit of heating these is that you can pose any way you want it. You literally only have to hold it (use gloves) for 3 minutes or so before you can let go. Also, let’s say you make a bend you don’t like. You can re-heat and do over. I know from experience! It doesn’t seem to hurt the material any.

    • Hi Carl,
      I don’t, that’s why I sent it to Jonni, whose many videos I have found SOOO helpful. Honestly, though, bending PVC is so easy that here’s my suggestion: just pull out a pipe for experimenting, make a few bends, and see how it turns out. You can re-heat and redo bends if you really have to, but I began first with just experimentation. BTW: Another way to make a PVC joint is to heat up the ends of two pipes, smash them flat in a vice, trim to rounds like a bone (they will actually be fanned out a little before you trim) then drill a hole through both and connect them using a bolt and nut. I didn’t do that for Rancor because it’s a lot of work and I didn’t need his arms and legs to move after the original pose.

  3. Wow – SO excited by this…thanks for a great tutorial!

    I had no idea a PVC pipe cutter existed, and I never wanted to deal with a saw, so I’d fuss building armatures with pipe insulation tubes with heavy guage wire inside. PVC will work SO much better – and be way easier. I have a heat gun already.

    This is so exciting…thanks for sharing your process!

  4. Clayton, thank you so much for this post! After reading your explanation, I can see that this would be a great way to make lightweight armatures for long-legged sculptures, like a stork or a giraffe. I have a lot of PVC pipe that I used for a garden experiment, and this would be a perfect way to use it. It was so kind of you to take the time to show us how to do it. 🙂


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