21x25 3D Pro 3.5" Deep K3 Stretcher Frame Kit

True 25:21 Custom Proportion - 21x25 Size

Check-out one of these other sizes in the same 25:21 aspect ratio:

42x50 • 63x75 • 84x100

• Super strong 3D™ Pro K3™ Stretcher Bar is a very popular among contemporary artists whose painting will be displayed without a frame.
• For this 21x25 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.

What is Sustainable Forestry?

To a forester, the term "sustainable" could mean exercising industry adopted forestry practices to maintain a forest indefinitely. To a logger, the process of proper care for the trees remaining after a harvest. To a landowner, their interest may lie in keeping their forest in the family. And to those of involved in the process of making and using wood-based art supplies, it can mean promoting and supporting an industry dedicated to the preservation of our precious natural resource. We can all do our part to care for our national forests.

Specially Dried and Heat Treated Lumber

Our wood is handpicked from a curated group of environmentally responsible lumber mills in the Pacific Northwest. By adhering to our precise drying and heat-treatment standards, these mills produce lumber with nearly half the moisture you'd find in common home improvement outlets or lumber yards. This meticulous process not only enhances the wood's strengthÑminimizing risks of cracks, splits, or bendsÑbut also elevates its dimensional stability. Such quality, despite its premium, is paramount in creating professional canvases designed to uphold the sanctity of your cherished art throughout the years.

31x35 is the Canvas Size Needed for this 21x25 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.

With deep family ties and a legacy spanning since 1965 in California, Masterpiece® has been the epitome of unmatched quality in Stretcher Bars across North America. Our commitment to pioneering excellence has crowned us as the forerunners in the world of professional fine-art canvases. Bolstered by our patented innovations, our products exude a caliber that's in a league of its own. One touch, and the unparalleled quality becomes palpable, leaving an indelible impression on your clients and all future admirers of your art.