Introduction: PVC Bungee Joints
If you have seen my other Instructables you already know I have a soft spot for PVC. It is cheap, durable, and easy to find. This is the second in a series of Instructables giving you tips and tricks for using PVC in your projects. So without further delay, PVC Bungee Joints!
As with all my projects, I made it at Techshop! http://www.TechShop.ws
Step 1: Gather Materials
(1) Mini bungee cords
(2) 1 inch Binding Post
(2) 1-1/4 inch 8-32 screws (for 1-1/2 inch PVC)
Metal Filled Epoxy
Piece of coat hanger bent into a hook (length varies based on length of PVC)
Step 2: Determine the Stretch Length
My bungee was too long, so I slipped the hook to the other end, and tied a tight knot. Then I trimmed what I wasn't using.
Bend the bungee hook into a loop as shown. Repeat on the other end.
I like the joint to have a little tension when locked together, so I start by measuring the length of the bungee cord when taught.
I then add 3/4 inch to the measurement to make sure it will be nice and tight.
Step 3: Locate the Binding Post Holes
Take the measurement you obtained in the previous step (Taught plus 1/2 inch) and divide it by 2.
Measure from the center of the coupler to each pipe in the joint. Mark the pipe, use tape to protect the finish if it has been painted.
We need 2 holes directly across from each other, this is a quick method I use to line them up.
Cut the paper into a 2 inch strip to make it more manageable..
Wrap the strip around the pipe at the line you just drew. Mark the circumference
Now fold the paper in half aligning the edge to the line and crease the paper.
Mark the crease. This is exactly half the circumference of the pipe.
Wrap the paper around the pipe and mark the hole locations. One will be at crease and the other at the end.
Step 4: Drill the Holes
Drill the appropriate size hole for each side of the binding post.
I had a countersink, so I created a pocket for the screw heads.
Step 5: Install the Posts
Optional: (Lock the screw with epoxy)
Place a little epoxy in the binding post and perform the next step. This also works with Loctite, but I already had epoxy.
Feed the binding post half of the pin in, you can hold it temporarily with tape if you need to.
Pass the binding post through the bungee hook
Install the screw. Do not over tighten and compress the PVC.
Repeat on the other end.
I found I could stretch the bungee and hold it with my thumb while I set the second screw and binding post. If this doesn't work for you use the hooked coat hanger to stretch the bungee.
Step 6: Profit!
You now have a bungee version of a lock joint in PVC.
One thing I like about this is the bungee will hold the pipe in the unlocked position as well as the locked!