How To Shape Sintra Armor

One of the reasons Sintra (or PVC foam board) is popular is that it’s easily shaped with a heat gun. If you don’t have a heat gun you can use boiling water instead. Just place your armor plate in a large pot of hot water until it’s pliable enough to shape. I suggest you practice shaping on some scrap pieces to get comfortable.  (Note that hair dryers are not suitable since they don’t get hot enough.)  

To start shaping your armor pieces, get your work area and equipment ready. You’ll need gloves to protect your hands from the high heat. Try to use gloves that won’t leave marks on the Sintra. Keep in mind that your fingers can leave fingerprints or dents also.  

Have some curved objects ready to use as a form. A glass container, food jars, pvc pipe, a round tin can, a coffee cup for smaller areas, are all handy for getting smooth even curves. And of course, placing the Sintra on your own body will be essential to get the best fit. If you have an extra ceramic tile it makes a handy working surface. The edge of a countertop can also help curve the edges of armor pieces. To form subtle compound curves you can try the “dishing method” by using a dome-shaped or spherical object (like a banister top). I use a styrofoam ball to form female Mandalorian chest plates.  

How to shape sintra armor with heat gun.

Point your heat gun at the area you want to shape. Work in small sections, don’t try to do the whole piece at once. Move the heat gun around, don’t stay in one spot, and heat both the top and the bottom of the Sintra to get even heat distribution. If you leave the heat gun in one spot too long you risk scorching or warping the Sintra. This is why I recommend buying white Sintra since you’ll easily see the plastic start to brown. You can sand scorch marks, but warping is a bit more difficult to fix. You want to heat the plastic just enough that it’s pliable but not too floppy.

Remember “happy accidents”, if something goes wrong, you can usually call it weathering or “battle damage”. Watch the videos below for good tips on heat shaping Sintra or PVC sheets.

For backplate shaping watch this Facebook video,

Once you are satisfied with your shaping, some people like to spray cold water to the area to help the Sintra cool quicker to hold the shape.  You might also like to mark the inside of the armor piece with “left” or “right”. Our bodies aren’t always perfectly symmetrical.

Lastly, sand the edges with a fine-grit like 320 sandpaper to smooth out any rough areas.  Clean and remove the dust from your armor pieces, to prepare them for paint primer. Oils from your fingers can sometimes affect paint adhesion.

Keep in mind when making your Mandalorian costume that everything will take longer than you expected. And your kit might even look mediocre to you. But you will eventually see a transformation once it’s painted and all the different pieces are put together. Don’t give up. Shaping the armor pieces to fit your body can be time-consuming and really frustrating, especially if you don’t have someone to help you nearby. If you do get frustrated, remember the joy that you will be giving children and adult Star Wars fans. If you need to, take a break, have a snack, or pet your dog. 

Go here for tips on shaping female Mandalorian chest armor plates.

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