Chair suspension seat design

[Mark Singer]

I installed Pirelli rubber webbing in the chairs I just finished. This repaced the solid wood bottom. The reason I made the change was that the down ,feather and foam combination was allowing the seat to "bottom out". This adds comfort as you sink in te geometry changes. I made a molding that has an angled kerf of 70 degrees that accepts the special clips . It is just a tad wider that a saw cut. The strapping and clips are available from an upholstery supply store. You cut the straps to exactly the correct length because there is not much stretch in the webbing. It really gives a great feel as you sink in. It was popular on many Danish chairs.

[Mike Henderson]

Looks like it would make a comfortable chair. Did you get that webbing locally or did you order it through the Internet?

Mike

[Jamie Buxton]

I've never understood what those straps buy you. It's not that I think they're bad, I just don't understand.

You could design a chair with a plywood bottom with a cushion, or with a strap bottom with a cushion. In the plywood-bottom design, all the compliance is in the cushion. In the strap-bottom design, some of the compliance is in the cushion, and some is in the straps. You can make cushions with a wide variety of stiffness by choosing the materials carefully -- foam can range from stiff-as-a-board to extremely-squishy. You can even make cushions with a softer material (foam or dacron batting) on the top, for that initial softness, and stiffer foam in the middle to prevent bottoming out. If this is a new design, you're going to be messing around with cushion-material selection anyhow. So why add one more element -- the straps?

[Mark Singer]

Looks like it would make a comfortable chair. Did you get that webbing locally or did you order it through the Internet?

Mike
A-1 Foam and fabrics in Santa Ana on Main Street, cheaper by the roll

[Mark Singer]

I've never understood what those straps buy you. It's not that I think they're bad, I just don't understand.

You could design a chair with a plywood bottom with a cushion, or with a strap bottom with a cushion. In the plywood-bottom design, all the compliance is in the cushion. In the strap-bottom design, some of the compliance is in the cushion, and some is in the straps. You can make cushions with a wide variety of stiffness by choosing the materials carefully -- foam can range from stiff-as-a-board to extremely-squishy. You can even make cushions with a softer material (foam or dacron batting) on the top, for that initial softness, and stiffer foam in the middle to prevent bottoming out. If this is a new design, you're going to be messing around with cushion-material selection anyhow. So why add one more element -- the straps?

Jamie,
It makes a huge difference. It changes the entire geometry and you sink in more and the back of the chair starts really working!

[Ed Labadie]

Mark,
I've really enjoyed your posts on the making of these chairs. They turned out beautiful!
Thanks for taking the time to share it.

Ed