Using closed-faced 80/20 extrusions is usually considered more aesthetically pleasing to the eye, but you can go one step further by pairing them with quarter round extrusions and special 3 way corner connectors.

In the photo below, we are using the extrusion 1517-LS which is a 1.5" quarter round t-slot with a 1.123" radius curved "closed" back. It has two slots on the unseen side. As you can see, it is paired with the standard rectangular 1504-LS for the bottom horizontals (as using quarter rounds on both vertical and horizontal will leave a weird corner). While we don't really know how they connected the vertical to the horizontal by looking at the picture alone, it is probably with an anchor fastener on the bottom plane.

Up on top of this same vertical, a fancier connector is used for the corner - it's the 4441 3 Way - Rounded Corner connector. If you have a top shelf on your table, cart or frame - you might not use this type of connector as it would get partially covered. But if your frame doesn't have a top - or the top is using the inside slot - then using this type of decorative connector is an option.

As this type of connector is substantially more expensive than a standard internal fastener, we usually only recommend it for trade shows, corporate lobbies, product samples or customer centers. They are available for 1", 1.5" and 40mm extrusions.

Using closed-faced extrusions and decorative corner connectors can help you create a frame that looks a little less industrial and a little more modern. Check them out on your next build or have us design one for you.