HDPE Dowel Nuts for Break Down Furniture
I use an induction stovetop to heat up a steel pipe and cast HDPE plastic to make threaded inserts (the Threaded Beavers). I enjoy making furniture out of pallet wood and dowel nuts are helpful to help create knock down joints. They don't make them larger than 1/2" in diameter. —
Step 1 - Obtain tools and materials
Amazon induction plate: https://www.amazon.com/AmazonBasics-1800W-Portabl...
Cast Iron Pan: https://www.amazon.com/Lodge-Griddle-Pre-seasoned...
or stainless steel plate adapter: https://www.amazon.com/9-45inch-Diffuser-Stainles...
Propane torch: https://www.homedepot.com/p/Bernzomatic-WK2301-Pr...
Scrap conduit (1" Inner diameter)
construction hard hats
Silicon Gloves: https://www.amazon.com/Gorilla-Grip-Silicone-Prof...
Wood for bench:
Laminated pallet wood for the legs
half lapped pallet wood for the backrest
3/4" pallet plywood
Step 2 - Cut up or shred the HDPE
Step 3 - Melt HDPE
I had a scrap cylinder of steel which I was also able to heat up on the induction plate and it helped with rolling out the plastic into a sheet.
See the video link here at ~3:00 mark where I start melting plastic.
Step 4 - CAST HDPE
After filling the pipe, I use a clamp and some 1" diameter plywood in the conduit to really get high compression in the conduit. I'm trying to keep the density of this HDPE as high as possible.
After clamping, the HDPE will tend to shrink so I'll tighten the clamps as the plastic & pipe cools.
Adding smaller pieces and compressing down frequently seem to get the best results but I haven't mastered this process yet.
Step 5 - Cut, Drill, & Tap the HDPE
I drilled a hole into the center, and tapped the hole using a 3/8" x 16 N.C. tap and followed the tap with the actual bolt I used.
To make the bolt easier to enter the hole, I also used a countersink at the bolt entrance holes.
One of the surprising discoveries to me was how strong the thread held. Even using my impact driver, I didn't seem to strip the thread. I also installed some bolts adding a nut on the flat side of the Threaded Beaver and I'll check the differences as the temperature changes.
Step 6 - Use the Threaded Beavers
For 2x wood getting connected to the stretcher piece of wood, I countersunk a hole for the hex head bolt and washer to sit nicely in. This is not necessary but I thought it make this bench look a little bit higher end.
This bench structure I made was really just the bones of my bench, I cut some plywood for the seat and back rest which covers the structure.
Step 7 - Help me!
Thank you for reading and I hope that you can learn something from my current process.
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