21x40 3D Pro 3.5" Deep K3 Stretcher Frame Kit

True 40:21 Custom Proportion - 21x40 Size

Here are a couple of other sizes in the exact same 40:21 proportion:

42x80 • 63x120

• Super strong 3D™ Pro K3™ Stretcher Bar is a very popular among contemporary artists whose painting will be displayed without a frame.
• For this 21x40 large size frame, the frame provides the ultimate foundation for your art with increased strength and stability
• Provides a 3.5" deep stretched canvas which makes a bold and commanding display
• 1-1/4" wide Stretcher Bars
• All Bars have an exclusive groove on the inside perimeter of the frame to which cross braces and Diamond Corner Braces attach
• Solid Ponderosa Pine or Fir from the Pacific Northwest

3D™ Pro 3.5 Stretcher Bar • 1/2" Canvas Clearance

1/2" Canvas Clearance is the space between the Bar and the canvas. Generally speaking, more clearance reduces the risk of the canvas touching the wood and creating unsightly lines during painting. Our design provides the optimal clearance so as not to impact your painting, but still leaving enough wood to the maximize strength of the Stretcher Bar.

• Produces a 3.5" deep stretched canvas (Actual depth is slightly thinner)
• 1.25" wide Stretcher Bar
• All Bars have an exclusive groove on the inside perimeter of the frame to which cross braces and Diamond Corner Braces attach
• Solid Ponderosa Pine or Fir from the Pacific Northwest

Finger Jointed Wood is not meant for Stretcher Bars

Solid wood makes the most dependable Stretcher Bar, because one homogeneous wood member is going to behave similarly across the entire length of the Bar. Whereas, with finger-jointed wood is made-up of multiple pieces of wood, sometimes on the actual joint itself, presenting multiple points of failure which no one can control.

We only use Solid Wood to build our Stretcher Bars because a solid piece of wood will last indefinitely. When we speak of archival value, it's not just the paint you use and the quality of your canvas and ground, even the wood choices manufacturers add or reduce value to your final painting. The fact is, you don't want problems, and finger joints only increase that risk of the wood falling apart in the future.

The glue used to bind finger joints is a water based adhesive and when that wood is exposed to high humidity environments, particularly with exterior walls, the glue joints can give-up. As a manufacturer, Masterpiece® does its part to conserve as much wood as possible, and still provide a quality product that will out-perform any other in the marketplace.

Tree Replanting - Essential to Sustainably Managed Forests

Harvesting timber provides humans with an essential natural resource, but replanting trees at a rate higher than a harvest is a key component in humanity's effort to guarantee a healthy forest for the future. Increasing our number of trees is just as essential to our economy, as the harvest itself, which is why we select only timber harvested from responsibly managed forests.

Specially Dried and Heat Treated Lumber

We source our wood from a select group of top-tier environmentally conscious lumber mills in the Pacific Northwest. These mills specially dry and heat-treat the lumber to our specifications, resulting in about half the moisture content compared to wood from typical home improvement centers or lumber yards. This process makes the wood stronger, reducing the likelihood of cracking, splitting, or warping. While the wood we use comes at a higher cost, it ensures a more dimensionally stable end product. This stability is crucial for crafting fine professional canvases that support your invaluable art over time.

31x50 is the Canvas Size Needed for this 21x40 Frame

Please note that you will need a canvas that is at least 10 Inches larger than the actual frame size to ensure proper stretching. This will provide ample material to stretch the canvas and attach it to the back of the frame. If you prefer to attach the canvas from the edge of the stretcher frame, you can reduce the size of your canvas by approximately 3/4" all the way around the frame. This will allow you to paint on the edge of the canvas and hang your artwork without needing a separate picture frame. And, if you ever need to remove the canvas from the frame and re-attach it, you'll have enough material to do that too.

Tight'n'Up™ Liquid Canvas Retensioner

One of our most appreciated products helps make your canvas tighter! Stretching a canvas tightly can be a challenge. Our Frame Kits include the Corner and Brace Keys that you will need to add tension, but Tight'n'Up™ Liquid Canvas Re-Tensioner is a way that you can use to add tension to the canvas without needed to use the keys. It canvas be sprayed on the back of a canvas to repair most canvas tension issues.

With Tight'n'Up™, you can add tension to just a small area, or a large area. Simply spray it lightly on the back and brush it into the canvas, and within seconds, your canvas becomes tighter and stays tighter. The more you use, the tighter it gets. Recommended for acrylic primed cotton or linen canvas. We do not recommend it for oil primed canvas because there are simply too many different types of oil primed canvas, but used conservatively at your own risk, it will tension any canvas.

Rooted in California and flourishing since 1965, Masterpiece® takes pride in its family-led legacy of crafting North America's premier Stretcher Bars. Our quest for excellence isn't just a goal but a commitment, positioning us as the trailblazers in the domain of fine-art canvas. Our innovative patents have set new benchmarks, ensuring our offerings stand unmatched. Dive into the tactile experience of our products, and you'll instantly recognize the distinct Masterpiece® quality, a signature appreciated by both your clientele and future art connoisseurs.