bending plywood, woodworker

Bending Plywood

Whether you’re building a chair, constructing a skateboard ramp, or working on a model, bending plywood might be part of the process. There are several different ways to bend plywood. The best method to use depends partly on the size of your project, partly on the type and thickness of the plywood being used, and partly on the resources you have available.

How to Bend Plywood

When bending plywood sheets, it’s a good idea to use multiple thin sheets and bond them together, rather than using one thicker sheet. This process takes a bit longer but it provides visually pleasing results – perfect for furniture and other projects where appearance is a primary concern. Baltic birch is an excellent choice.

Whichever of the following plywood bending methods you choose, ensure that you work slowly. This allows the wood’s fibers to stretch gradually, reducing the risk of cracking or breaking.

bending plywood, woodworker
Bending plywood, Theron Burger

Bending Plywood in Molds

Build molds to your desired specification. MDF is a good product to use for this purpose as it is strong enough to keep the plywood contained. Cut pieces of thin plywood to fit inside the molds. It’s a good idea to make your plywood pieces longer than needed and trim off excess later. Working quickly, place your plywood strips into the molds one at a time. Cover the top of each strip with a generous layer of wood glue before adding the next strip of wood. Clamp the mold together tightly and allow the to set for 8 to 24 hours depending on size and shape.

Kerf Bending Plywood

This is one exception to the bending plywood thickness “rule” about choosing the thinnest sheets possible. You can kerf bend plywood over ½” thick with ease. Choose plywood for kerf bending carefully: Birch or Baltic birch is an excellent choice. Use a kerf spacing calculator to determine how many cuts you’ll need to make and how far apart to space the cuts for kerf bending. It’s also a very good idea to make at least one test bend on a scrap piece of wood if you have one available.

Once you’re confident that your calculations are correct, use a radial arm saw or table saw to cut the slots in the plywood. If the cuts are too shallow, your plywood won’t bend successfully; if they’re too deep, the piece will break rather than bend.

After the initial cuts have been made lengthwise, use a circular saw to cut into the kerfs. This adds more flexibility and makes room for hidden splines. When you’re ready to bend, fill the cuts with wood glue and carefully bend your piece into the desired shape. Push the splines into place and allow ample time for curing – a week is ideal for items like tables and chairs. When finished, sand the glue and use wood filler to conceal it before finishing your project as desired.

Bending Plywood with Steam

You might think that steam bending plywood is the way to go for all kinds of projects, but this method is best for small pieces such as model parts. The reason for this is that unless you have a huge vessel that you can maintain at a steaming hot temperature, it’s impossible to maintain moisture and heat long enough to adequately steam plywood for bending.

Start by deciding how to mold your wood once it comes out of the steamer. Set up 2x4s, clamps, molds, and other materials beforehand so you can go straight from the steamer to the shaping form you’ve chosen.

Next, set up your steamer pot. Wear a pair of heat-resistant gloves, and insert your plywood into the steamer basket. Cover the pot with a lid and allow the wood to steam for an hour per inch of thickness. If your wood is 1/8 inch thick, it should steam for about 7 ½ minutes.

When the plywood is ready to come out of the steamer, don your gloves again. Carefully remove the wood and manipulate it onto your molds as desired. Clamp it into place and leave it to dry completely.

Heat Bending Plywood

You can use a combination of water and heat to bend some types of plywood. While fir and pine don’t respond well to this method, birch, poplar, and mahogany often turn out very well.

Start by building a mold with MDF, or simply create a frame with 2x4s. The method for building your mold or frame will vary depending on the type of project you’re working on, as well as the size of the plywood you’re planning to bend.

Lay your plywood flat and mark a crease line where you’ll be applying pressure to bend the wood. Soak towels in steaming hot water (wear heat resistant gloves for this) and place them on the crease line. Leave the towels in place for several hours or days, depending on the size of the plywood sheet. You can speed the process significantly by applying heat and moisture to both sides of the wood. Continue to re-wet with hot water as needed, until the wood is flexible enough to bend easily.

Use clamps or a ratchet strap to hold the plywood in place as you bend it. Work gradually, particularly if you’re bending thick plywood. Depending on the size of your project, it could take hours or days to get the bend fully into place. Keep the crease line wet while you work on the bend.

Once you have achieved the desired bend in your plywood, remove the towels and leave the clamps and/or straps in place. Allow the wood to dry slowly – don’t try to speed things up by adding a fan or heater. Leave the wood in place for several days, for best results.

Once the plywood has dried, check for cracks. You can fill these with wood filler and sand it out to create a smooth, desirable appearance, then finish as desired.

How to Bend Plywood for a Ramp

It’s surprisingly easy to bend plywood for a skate ramp. Start by using an online ramp tool to calculate dimensions and determine which supplies to purchase. Note that the best plywood for skate ramps is 3/8” or thinner. Once you have built your frame according to specs, lay your plywood onto the frame. Start from the bottom. Get friends to stand on the plywood and bend it gradually as you carefully screw it onto the frame. If you like, you can get the plywood wet before you start – but this means that you’ll have to wait for it to dry completely before applying a weather-resistant finish.

Bending Plywood in Two Directions

You can use any of the methods outlined above to bend plywood in two or more directions. Work slowly, set up your molds and/or braces ahead of time, and make your calculations carefully. If possible, try your bending process with a piece of scrap wood before moving on to your main project. It’s worth noting that bendable plywood might be best for projects that call for multiple bends in different directions, as this product is designed specifically for the purpose of bending.

Choosing Bendable Plywood

While it’s possible to put a mild curve in most types of plywood, not all plywood is truly bendable. Spend a little time looking into the different products available for your specific project to determine which one will be best. If you’re working on a model, an art installation, or a piece of furniture, it’s a good idea to look into products labeled as “flexible board” or “bending plywood.” These types of bendable plywood are designed to flex in different directions without cracking, and they can take on the shape of nearly any contour.

Look for bendable plywood products such as Radius bending plywood, which can bend in cross-grain directions as well as long-grain directions. These products are the most versatile of all. They come in a variety of thicknesses, and will provide you with the appearance you desire.

Uses for Bendable Plywood

Bendable plywood is amazing stuff, and once you start using it, you might find yourself looking for more excuses to add projects to your list. Here are some great ways to use bendable plywood in your next project:

  • Create curved columns
  • Make decorative arches
  • Build furniture
  • Build unique cabinetry faces

It’s worth noting that thin, decorative bendable plywood isn’t typically suitable for exterior use. Reserve this specialty product for interior projects.

Bonus Shortcut: Try Pre-curved plywood

If you’re in a hurry or you lack the appropriate tools for bending plywood, don’t despair. Pre-curved plywood comes in a vast variety of configurations large and small alike, so you can complete your project with far less effort. If you aren’t able to find pre-curved plywood locally, a quick search will yield several online sources to choose from.

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