Sintra® is available in thicknesses from 1mm to 19mm (but 3mm and 6mm are the most common), and a dozen colors (white is available in all thicknesses, the other colors just in 3mm and 6mm; more about colors later). As a result of its structure, Sintra® has a number of useful properties .

• High stiffness
  
• Light weight -- half the weight of solid PVC in gauges of 1 - 6mm, slightly over one third the weight of solid PVC in 10mm and thicker gauges
  
• Resistance to moisture and many chemicals
  
• Smooth solid faces -- just the ticket for ease of finishing, as well as resistance to grime buildup
  
• Easy to work with (but more on this below)

Cutting, machining, and forming
Sintra® can be shaped much like wood. Pieces up to 3mm thick can be cut with a good shop knife; 6mm sheet can be scored with a knife and snapped on the score line. For speed and a very smooth edge, you can also cut Sintra® with a circular saw, table saw, band saw, or router. After you're done cutting, you can smooth any rough edges with a file, or with medium grit sandpaper.

 

Thanks to a few Star Wars fan sites (Sintra® seems to be a big hit with the home-built costume crowd), I ran across another interesting item -- Sintra® is a thermoplastic, and starts to soften at about 150° F. This means that you can easily heat up thin (3mm or thinner) pieces of Sintra® and mold them as needed. To bend a piece of Sintra®, you just boil it in water for 10 - 15 seconds (the length of boil determining how soft the material gets). After boiling, remove the piece with tongs (gently, so as not to leave an imprint of the tong in the piece), quickly bend it to your desired shape, and freeze it in shape with cold water. If you mess up, it's no problem -- keep your water boiling, and you can just repeat the process. For what it's worth, you can bend thicker pieces of Sintra® as well, although boiling water probably isn't hot enough to do the trick.

Hello, Dali!   Sintra® brings a whole new flexibility to BEAM bot design

As a note of warning, be careful not to crush Sintra® while you're manhandling it -- crushing destroys the material's internal cell structure, leaving you with a very flexible and essentially useless mess.

Sticking pieces together
When the time comes to put pieces of Sintra® together in a durable way, you have two paths you can follow -- namely, the use of adhesives and / or fasteners. I'll discuss fasteners in a bit; as for adhesives, well that's the subject of the next page.

1. Other vendors produce products comparable to Sintra®; these are sold under the brand names of Kömatex® (by Kömmerling), and Celtec® (by Vycom). Thanks to Sintra®'s market dominance, though, it's the brand name you'll most often run across, and is often (if inaccurately) used as a generic term for PVC foam board.

2. For those who may need such information, I've hosted a zipped copy of the SINTRA material safety data sheet (MSDS) here.

Sintra: Sintra material is closed-cell, expanded plastic, high-density polyvinylchloride sheet. Sintra is a homogeneous material that allows the ease of cutting without regard for grain. At half the weight of solid PVC, Sintra may be stapled, nailed, riveted, glued, and thermoformed. Forming may be done on conventional forming machines. Because this material is not hydroscopic, it needs no drying pre-forming. Sintra is available in 9 thickness' 1mm-13mm all thickness' are available in white, some thickness' are also available in black & colors. (white, black, light gray, dark gray, beige, dark red, green, yellow, blue and dark blue)

Ever Think of making a suit of Armor?

It is recomended that you look for 1/8inch sheets of Sintra to make your costume, although you should decide what thickness is best for you.
The great thing about Sintra is you can make just about anything with it. It's durable, easy to mold (providing you buy the 1/8" thickness), and holds paint very well. It can be molded without expensive presses or vacuum tables. All you need it a big pot of boiling water and cold tap water nearby!

First you should make cardboard test pieces of your armor to use as templates. These will allow you to "fit" your armor to your body shape first and not waste the Sintra. After you have the right size, trace your templates onto the Sintra sheet using a permanent marker.

Now it's time to cut out your pieces.
Use a Dremel or similar tool with cutoff sanding wheels for cutting through Sintra

Try to avoid using the cordless versions of the rotary tool, battery power will run out too fast. Possibly leaving you in the middle of a cut. The Dremel or similar rotary tool, with it's variety of tips available is one of the most essential tools for cutting and constructing your costume. This one tool will eliminate the need for jigsaws, grinders and beltsanders.
When cutting the pieces out, be sure and leave a 1/16" or more outside the line. The dremel will also leave some burs on the plastic, but don't worry about that at this point.

Now it's time to mold your armor.
Most suggest to boil the Sintra Pieces on an electric range or gas stove. To do this,you mus tfirst bring a BIG pot of water to a low boil. Try to use the largest pot possible for the larger pieces. (The bigger the pot the better.) If you're working with small pieces, a smaller pot will be fine.
Turn the faucet on cold water and have it running and ready. When the water starts to boil place your pieces One At A Time in the pot for 10-15 sec. The longer it stays in, the softer the piece will become. Use tongs to remove the piece and bend/mold it to the desired shape with your hands. The Sintra will be hot, but it's usually not so hot you can't touch it. If it is too hot, wear some gloves.
MOST IMPORTANT- while you're holding the armor to the shape you want, run COLD tap water over the piece. This freezes the molecules in the plastic and the Sintra will hold it's shape. One of the best aspects of Sintra is, that if the shape you just formed is not exatly the way you want it, just repeat the process until you get it right. Once the pieces are formed correctly, you're ready to proceed.

Next step is to remove any burs and smoothen the pieces.
Use a flexible sanding block with heavy (40) grit finish to remove the burs and straighten the edges. This will sand the shape quickly, Then, once it's close to the desired shape, move down to a 100-300 grit paper to bevel the edges to a smooth finish. Continue to lightly sand the entire surface area, creating a very slightly rough surface for the paint to stick to. Aditionaly if you choose to, the prep work can be finished by using the dremel with a grinding tip to "dent" your armor pieces. Be careful not to do too much or sand through the pieces.

A great technique for a acheving a smooth surface with epoxy putty ( especially the edges for better blending) is, instead of just wetting your fingers with water to smooth the stuff down, take VICKS VAPO-RUB and use it to smooth it out. It really helps lessen sanding later. There are solvents (mineral oil and turpentine) in Vapo-rub (or a cheaper generic
equivalent) that are believed to be the factors that allow this to work so well.

This same technique can be used with "squadron" type model putties or red
auto putties, by replacing the "Vapo-Rub" with fingernail polish remover.

 1. What is Sintra?
Sintra is a lightweight rigid board of moderately expanded closed-cell PVC, manufactured by Alcan Composites USA Inc. in Benton, Kentucky.

2. How is it used?
Typical applications include screen-printing, signage, exhibits, displays, and photomounting as well as some original equipment manufacturing.

3. What gauges of Sintra are available?
Sintra is produced in 9 gauges. 1-6mm, 10, 13, & 19mm.

4. Does it come in colors?
Sintra is available in 12 colors.

5. What does Sintra weigh in comparison to solid PVC?
Sintra is half the weight of solid PVC in gauges of 1-6mm. (0.700g/cm3) Sintra is slightly over 1/3 the weight of solid PVC in 10, 13, &19mm gauges. (0.500g/cm3)

6. How do I cut Sintra?
Up to 3mm thick can easily be cut with a knife. Thicker sheets should be cut with hand circular or saber saws. Sintra also can be shaped easily using a router.

7. Can it be die-cut?
Flat pieces of Sintra can be die cut with steel rule dies in the same way as other solid plastics. Best results are obtained using thin rules with long faceted bevels.

8. How do I bond Sintra to itself?
For bonding Sintra to itself, the same solvent type adhesives that are used for rigid PVC Pipe s give excellent results.

9. How do I bond Sintra to other materials?
For joining Sintra to other substrates, solvent-dispersed adhesives formulated for PVC bonding may be used, as can most neoprene-based adhesives.

10. What happens to Sintra when used outside?

• Sintra will change colors when used outdoors. The amount of color change depends on the original color, UV levels, and other exposure conditions. This is true of all materials that use organic pigments.

• Sintra expands and contracts with temperature changes. This must be taken into account when mounting large sheets of Sintra outdoors.

• Sintra, like most plastic materials, has less impact resistance in cold conditions. Thinner gauges have less impact resistance than thicker ones. For this reason 6mm should be the minimum gauge used for outdoor signage.

11. Why must I keep Sintra under 150F?
Foamed extruded plastics contain internal stresses. These stresses relieve themselves at elevated temperatures. If Sintra is allowed to reach 150F it will no longer remain flat and will warp and bow.

12. Can I paint Sintra?
Sintra can be easily painted using PVC compatible paints. Recommended paints include: vinyls, acrylic laquers, and two-component polyurethanes. The use of primers is not normally required. The surface should be cleaned with isopropyl alcohol.

13. How can I prepare the edges before painting?
When Sintra is cut to size during fabrication, edge cells are exposed. Smooth edges can be achieved with a file, plane, or sandpaper. The use of a PVC solvent will chemically collapse the cells or prior to painting, a filler such as spot putty will produce an edge similar to the surface texture of the sheet.

14. What photomounting methods can be used with Sintra?
Since Sintra will warp at temperatures about 150F it cannot be dry or hot mounted. Colds mounting in cold roller laminators, cold vacuum mounting, or hand lamination all give excellent results.

15. Can Sintra be screen-printed?
Screen-printing is easily accomplished with Sintra due to its excellent surface finish. Vinyl and vinyl/acrylic, solvent based inks are compatible with Sintra. Screen-printing inks should air dry rather than be heat dried. Temperatures above 150F may cause warping of the Sintra. UV inks can also be used but care should be taken to keep from overcooking the ink and possibly making the printed Sintra brittle.

16. What are the fire characteristics of Sintra?

• Sintra material will not support combustion by itself. It requires a flame source to burn. Sintra is a self-extinguishing material and will not continue to burn after the flame source is removed.

• All gauges of Sintra pass the criteria of UL 94V-0, and UL 94-5V. These are industry standard fire tests.

• Thinner gauges of Sintra, 1-4mm, also pass ASTM E-84 which is also known as the UL Steiner Tunner Test.

17. Can Sintra be heat bent and thermoformed?
Sintra is a thermoplastic that can be heated and bent or formed into various shapes. Once the material cools it retains the shape it was formed into.

18. What are the limitations when vacuum forming Sintra?
Sintra is most suitable for large-faced and smoothly contoured parts. The radius and depth of draw is generally limited to the extent that the surface of the material can stretch.

19. Is Sintra recognized by UnderwriterÕs Laboratories UL?
Through and ongoing certification program with UL, Sintra is recognized as a Component Ð Plastic and Component Ð Sign Accessories. Using UL recognized components can speed the UL listing process when manufacturing electrical signage.

attributes of Sintra  material include its being "Acid Free" and having minimal "Outgassing" qualities.

Outgassing Both .700 specific gravity and .500 specific gravity Sintra materials have exhibited <0.001% HCL