Making Bracelets From Recycled HDPE
NOTE: This tutorial is in need of revision. Any comments and suggestions are greatly appreciated.
High Density PolyEthylene (HDPE) is one of the most commonly used plastics today, being used in a wide variety of items from tiny pill bottles to large barrels and water storage tanks. Chances are that in the last 24 to 48 hours you have carried groceries home in plastic shopping bags made of HDPE, drunk juice or milk from an HDPE jug, or pop from a bottle with an HDPE cap, thrown dirty clothes into a plastic clothes hamper made of HDPE, washed your hair with shampoo from an HDPE bottle, and thrown several HDPE jugs and bottles into a recycling box, also made of HDPE.
I first got interested in recycling HDPE about a year and a half ago, after stumbling across a few videos on the subject. The idea of remelting HDPE intrigued me, doubly so, because the resulting blocks and sheets can be cut and worked with ordinary woodworking tools as easily as wood. (i.e. My bandsaw chews through HDPE as easily as the softest pine.)
I have spent most of the last year doing only occasional melting experiments, without any clear projects to make from the resulting blocks. However, with Christmas coming up in a couple of months, three nieces to get presents for, and not a lot of money in my pocket to buy said presents, I have finally thought of a use for my HDPE. This year, I am going to make bangle bracelets for my nieces to wear.
- High Density PolyEthylene from various bottles and plastic bags
- Dish washing detergeant for cleaning HDPE containers
- A solvent such as Goo Gone or Goof Off to remove label adhesive from containers. WD40 also appears to work for this purpose.
- An expendable pair of scissors or heavy duty shears to cut jugs, bottles, and other HDPE items into smaller pieces
- Containers for storing the HDPE pieces
- A 4 inch (10cm) diameter soup can to use as a mold
- A can opener for opening the can
- An oven with temperature controls
- A saw for cutting a wooden disk
- 5 inch C-clamps for compressing the HDPE. A jack, such as a scissor jack or a bottle jack may work as well.
- A wooden disk for compressing the HDPE
- Scrap wood
- Aviation snips for cutting the 4 inch can
- A pair of pliers for tearing open the can
- A hammer and 2 chisels to separate the wooden disk from the HDPE blank
- A centre finder (home made) to find the centre of the HDPE blank
- A drill press (optional) or hand drill.
- A heat gun for remelting small areas of the HDPE. A wind proof lighter *might* also work for this purpose (I have not tested this).
- A lathe
- Lathe tools (parting tool, gouge, and skew chissel)
- A caliper or ruler
- Several grades of sandpaper
- A spindle sander or drum sander (optional)
- The patience of Job (required)
Step 1: Obtain Some HDPE
HDPE is one of the most common plastics today. It is most commonly found in the form of blow molded containers used for food and cleaning products.
If you look on the bottom of most containers, you will find a triangle or recycling symbol with a number in it. The number for HDPE is "2". Other numbers are for different plastics, and should not be used. Under the triangle/recyling symbol, you will usually find "HDPE" written in raised letters.
Note: In some countries, you may find it written as "PEHD" instead.
Another source of HDPE is plastic shopping bags. Most shopping bags used in stores are HDPE.
Step 2: Rinse Your Jugs and Bottles
Next you need to rinse out rinse out your jugs and your bottles.
This is pretty much as one would expect, and so I am not going to bother with photos for this step.
Simply remove the cap from your container, partially fill the container with water, then replace the cap and shake vigorously for a few seconds. Then dump the water out of your container, and repeat.
For containers used for food or chemicals, you will want to add a few drops of dish detergent to help remove any residue on the inside, then rinse at least twice to make sure the container is clean.
For soap, shampoo, or detergent bottles, you will need to rinse the container several times, until the water runs clear.
Remove any caps, spouts, or other accessories from the container, and discard them back into your recycling box.
Set the containers to dry.
Step 3: Remove Any Labels From Your Containers
This step is complicated by the fact there is more than one type of label.
- Paper labels are the ones most of us are familiar with.
Lift one corner of the label using a fingernail, and carefully peel off the label.
Paper labels have a tendancy to tear. Filling the container with hot water will heat the label's adhesive, softening it, and making the label easier to remove.
After removing the label, you need to use a solvent, such as "Goo Gone" or "Goof off" to remove any torn bits of label from the container, and any remaining adhesive. "WD40" may also help.
The solvent will then have to be washed off the container with soap or detergent, and water.
- Another type of label made of a thin sheet of plastic is very common on shampoo and other beauty products' bottles. These tend to be much easier to remove than paper labels. They are also attached to the bottles with adhesive, which will also need to be removed the same way as the paper labels.
Many laundry detergent bottles have a strange sort of plastic label. The label has a paper like feel to it, but is actually a plastic, and is very difficult to remove, usually requiring a lot of scraping. It is often easier to just cut out around this sort of label.
Some labels are printed directly on the container, and can not be removed.
Step 4: Cut Up the Containers
Using an expendable pair of scissors you don't mind ruining, or (better) a pair of heavy duty shears, cut your container up into (roughly) fingernail sized pieces.
Please note: Cutting up containers is difficult work. If you don't already have forearms like Popeye, you soon will. Your forearms will be sore arms, and your carpal tunnels will hate you.
If your container has printing on it, or has the paper like plastic labels mentioned earlier, you will want to cut it out and set it aside or discard it.
Store your HDPE pieces in clean, dry containers.
Step 5: Separate Your Colours!
As you break your containers down into smaller pieces, you will want to separate your different colours from each other. This will allow you to choose whether you want to use "pure" colours, or choose to mix different colours in combination.
Just how picky should you be about separating your colours?
It is all up to you.
You can choose not to separate your colours at all, or you can separate your colours into basic cetegories (red, green, blue, et cetera), or you can even go to the extreme of having different containers for shades and hues used by specific brand names!
For example, I originally started out by having a mix of all of my colours, because I had very little HDPE available. As I began to get more, I began separating out the pieces from white jugs and bottles to be used separately, then I began to have containers for blue, green, and yellow. I then decided there was too much variation between greens, and began dividing them into three categories, then the yellows, and finally other colours as well.
Step 6: Prepare to Make Your Blank
Now that you have our HDPE plastic ready to go, you can finally start working on your bracelet.
First, you will want to make a solid plastic blank.
An Empty Can For the Mold
To make the blank, you will need a cylindrical mold just slightly larger than you want the finished bracelet to be.
A 4 inch (10 cm) diameter steel soup can will be ideal.
Open your can with the type of can opener that does not cut the entire top off the can. You want the lid to be able to fit inside the can.
Empty the can. Fill your belly.
With your hunger satisfied, wash and dry the can, and the lid, and remove the label from the can.
Create A Round Wooden Disk
Using a bandsaw or scrollsaw or jigsaw or coping saw or other saw capable of cutting curves, cut out a circular wooden disk just small enough to fit inside the can.
This disk will be used for compressing the molten plastic later.
Step 7: Fill Your Mold With HDPE
Take some of your HDPE pieces and partially fill your can.
NOTE: If you separated your colours earlier, you can mix those colours to create an attractive combination of your choice.
I fill my can to a depth of a little more than three inches. The more HDPE, the larger the blank will be, and the wider the bracelet will be. 160 grams of HDPE is a bare minimum. More is better.
(The green and orange blank used in most of the photos of the lathing process used 220 grams of HDPE.)
Place the can's lid inside the can on top of the HDPE.
The lid will prevent the HDPE from scorching in the oven, and will provide way of separating the wooden disk from the plastic blank later.
Step 8: Place the HDPE Into the Oven to Melt
Place the can with the HDPE into the oven.
Set the temperature to 380°F (190°C), and set the oven timer for two hours.
Why Such A High Temperature For So Long?
The temperature that is usually recommended for melting HDPE is 350°F (180°C), but I am setting it a little higher. I am also leaving the HDPE in the oven for a longer period of time. This is based on a past experience with melting HDPE.
In one of my earlier experiments in melting HDPE, I put the HDPE in the oven at 350°F for an hour. I ran the resulting block through the bandsaw later, and was surprised to see pieces of HDPE spilling out of the block like candy from a piñata. Only about half an inch (12mm) of the HDPE had melted around the outside, while the rest of the block remained as loose HDPE pieces.
So I am using the higher temperature and longer time to ensure the HDPE melts completely through to the centre.
Step 9: Compress the HDPE
The HDPE used in bottles does not melt into a runny liquid like other materials when heated. Instead, it becomes more of a soft putty with a consistancy similar to chewing gum.
In order to form it into a usuable solid, the HDPE will need to be compressed with a considerable amount of pressure to drive out the air pockets and squeeze it into the shape of the mold.
Remove the can from the oven.
Insert the wooden disk into the can, on top of the lid.
Using a 5 inch (13cm) C-clamp, apply pressure to the HDPE. Use a piece of scrap woodbetween the clamp and the bottom of the can to prevent the can from being crushed.
NOTE: If you do not have a usable clamp to apply pressure with, you can also use a jack in combination with a suitable frame to push against to compress your HDPE.
The wooden disk has a tendency to tilt to one side or another as the pressure is applied. You may need to use a second clamp to reduce this tilt.
If you choose, you can place the HDPE back in the warm oven, and allow it to cool slowly.
Step 10: Remove the Blank From the Mold
Once the HDPE has cooled, you will need to remove it from the can.
In most cases, the blank will be stuck firmly in the can.
To extract the blank, first find the seam on the side of the can.
Use a pair of aviation snips to make a cut parallel to the seam on either side of it as far down as you can go.
Use a pair of pliers in a manner similar to a sardine can key to tear the metal of the can by turning. The width of the tear will quickly narrow down until it is very narrow, but it should continue along the seam until it reaches the bottom of the can.
Flex and pull the sides of the can to loosen the blank.
The blank should now be able to come out of the mold.
NOTE: It is not always this easy to remove a blank from a can. While most cans I used did release their blanks as easily as shown here, some cans stuck tight to their blanks and had to cut and peeled away with considerable effort. Nearly all of my blanks made using pea soup cans (Habitant pea soup. Yum!) or tomato cans came out easily, using the method described and depicted above. Two blanks made using pineapple cans would not seperate from the cans, however, and required all of the metal around the sides of the cans to be peeled away with pliers, like flower petals.
Step 11: Separate the Wooden Disk From the Blank
You have probably noticed by now that the pressure you applied had caused some of the molten HDPE to flow up past the can lid and around the wooden disk, gluing it in place. Now you will need to separate them.
The lid of the can is the secret to removing the wooden disk. The HDPE does not stick to the metal lid as well as it sticks to the wood, making it a natural parting line. If you can insert a chisel between the lid and the blank, the two can be pried apart.
HDPE shrinks slightly as it cools. For me, this frequently causes the edge of the lid to be exposed on one side of the blank. (but not always!)
By hammering a chisel between the can lid and the blank, a gap can be opened up. (This will dull the chisel, so use a chisel you don't mind blunting.)
Once the gap has been opened, a second chisel can be inserted into it.
(A little brute force is required for this next step.)
*Carefully* push one of the two chisels away from yourself, while pulling the other towards yourself to pry the lid away from the blank. The thin line of HDPE holding the lid and blank together should tear, and the two pieces should separate.
Step 12: Mark the Centre of Your Blank
If you have a lathe with a jawed chuck, you can simply put the blank into the chuck, and away you go.
Whoopie for you. :-|
If, on the other hand, you are like me and have a lathe with a spur centre (a.k.a. drive spur, a.k.a. drive centre), you will need to find the centre of the blank in order to get it properly centred on the lathe.
In another instructable, I gave simple instructions on how to create a simple tool for finding the centre of a circle (or mostly circular object). This consists of a scrap piece of card stock with a 90 degree corner. The card stock is folded at the 90 corner, bisecting the 90 degree angle and creating a crease at 45 degrees. You then cut a slit in the crease to create your tool.
To use the centre finding tool, place it down on top of the blank, and line up the edges of card stock with the edges of the blank. Place a marking instrument (pen, pencil, awl, et cetera,) into the slit in the paper and draw a line using the slit as a guide. Then turn the tool to another angle and repeat the process. This will create at least two lines (in my case three) that cross at the centre of the blank.
Mark the centre with a straight sharp object, such as an awl, a nail, or a screw.
Step 13: Drill a Centre Hole in the Blank
Normally when I use wood on my lathe, I can just use the pressure of the tailstock against against the wood to make the centres sink in to the grain of the wood and hold the wood firmly.
HDPE is a little tougher than pine though, and so this doesn't work on HDPE.
We will have to drill a hole through the blank, and give the centres something to fit into.
A drill press is the best tool to use, of course, but a hand drill will also work if you are careful.
Simply line up the drill bit with the mark you made earlier, and drill a hole right through. :-)
Step 14: Heat the Bottom of the Blank for the Spur Centre
The spur centre needs to have its spurs embeded in the surface of the plastic in order for the lathe to spin the blank. As noted earlier, the spur centre can not sink into the plastic on its own. The spur centre would just spin against the surface of the blank, and not turn it.
Using a heat gun, heat the plastic in the area around the hole you just drilled to soften it.
When the plastic is soft, insert the point of you spur sentre into the hole, then tap the spur centre a few times with a rubber mallet. This will leave an impression of the spurs in the HDPE that the spur centre can grip into when the blank is mounted on the lathe.
NOTE: you may have to repeat the process more than once to make sure the impression is deep enough for the spur centre to hold onto.
Step 15: Mount the Blank on the Lathe
When you mount the blank on to the lathe, make sure the spur centre fits into the impression you created in the last step, and make sure the point of the centre on the tailstock is inserted into the hole in the centre of the blank.
Step 16: Facing Off the Blank
The blank is not perfect. It is likely the top of the blank was compressed at a slight angle. This is almost impossible to avoid. The bottom of the blank is not perfect either. Most cans have reinforcing ridges, and the shrinkage that occured as the HDPE cooled likely caused some distortion as well. This means the blank will be lopsided with an uneven weight distribution, which will will cause a lot of vibration when the the lathe is spining it.
Before you can start shaping your blank into a bracelet, you need to face off the ends of the blank. This will get rid of the vibration, and leave you with a pair of nice smooth ends to work with when you start shaping.
Step 17: Turn the Blank to Size
Using your gouge or your skew chisel, turn the edge of the blank until it is fully circular in cross section, and reduce the diameter to roughly the size you want the finished bracelet to be.
Step 18: Shaping the Bracelet
I decided to keep my bracelet shapes simple, and basically just rounded the edges over. For thinner bracelets, I chose to do a roughly semi circular cross section for the edge. For wider bracelets, like the one depicted here, I chose more of an oval cross section.
Step 19: Filling Bubble Holes
It is going to happen.
Just face it.
No matter how careful you are at trying to get rid of them, you are going to get holes from air bubbles showing in some of your workpieces.
The solution to this problem is simple.
There should be a fair amount of shavings around the lathe from your work so far. We will use some of these shavings to fill the hole(s).
Start by heating the area around the hole with the heat gun until the plastic around the hole begins to melt.
Using a pair of pliers or a pair of tweezers, place some shavings into the hole and melt them with the heat gun.
Use the pliers or tweezers to push the shavings into thole hole as they melt. Continue adding more shavings until the hole is filled.
Use a flat metal object, such as the side of a knife or a chisel, to press down on the melted shavings to ensure they are packed tightly into the hole.
Once the hole is filled, allow the HDPE to cool completely before resuming work on your bracelet.
Step 20: Sanding. Sanding. Sanding. Sanding. Sanding. Followed by Much More Sanding.
Oh dear lord! The sanding!
You might want to clear your schedule for this.
If you are looking for a glossy finish, expect to spend a lot of time on this part.
As tedious as it is, you will need to use several grades of sandpaper (and sanding meshes, if you can get them) to get the bracelet looking right.
Lower grits will make your bracelet look scratched and dirty, but will remove ridges and tool marks left by your lathe tools. As you move into somewhat higher grades, such as 600 or 800 grit, Your piece will appear smoother, and a fairly attractive matt finish will appear. At 3000 grit the bracelet should begin to look glossy. That should be enough for most people. However, if you are as insane as I am, you will go as high as 12000 grit for that perfect finish!
Use a slower speed when sanding.
At higher speeds, friction can melt the loose plastic dust between the sandpapaer and the bracelet. The melted plastic will then stick to the surface of the bracelet and create long unsightly streaks. The streaks can be scraped off easily with your fingernail, but you will need to stop your lathe in order to do it, and it can be long and tedious.
Using a slower speed will reduce or eliminate these streaks.
Step 21: Parting Off
Step 22: Trim and Clean Up the Inside
After parting off, there will be a thin ridge of material along the centre of the inside where the two cuts you made meet.
Using a sharp knife, carefully trim away any excess material. You can also use this opportunity to even out any missmatch between the two cuts.
To smooth out the inside, I used a sanding drum chucked into my drill press. This could also be done using a hand drill or a spindle sander, or even via hand sanding, if you are patient enough.
Using the sanding drum to remove material also allowed me to adjust the inside diameter of the bracelets slightly for more consistancy between bracelets, and a better fit.
Step 23: Give It to Your Favourite Gal
It's time to be a hero.
Colourful bangle bracelets made from recycled HDPE make excellent presents the ladies in your life will love. The smiles and appreciation you will receive from these unique gifts will make all of your hard work more than worthwhile.
Step 24: Save Those Scraps!
Don't throw away all those scraps and shavings! They can be melted down and used again.
All those fluffy shavings are a bit difficult to store, but all you need to do is place them on a baking sheet and heat them to 350°F (180°C) for 10-15 minutes, then flatten them with the underside of a pot or baking pan, to turn them into easy to store sheets you can place on a shelf, or cut into pieces to keep in a container.
Cores left over from the centres of bracelets, and failed bracelets can be cut into smaller pieces and remelted to make new blanks.
Step 25: Gallery
Some examples of bracelets I have done so far.
Step 26: Conclusion
The recycled HDPE bangle bracelets were a huge success.
My nieces loved them, and were thrilled to discover I had made them myself. It gives me a smile every time I see one of them wearing one of the bracelets I made.
When my ex-girlfriend discovered what I was doing, she insisted I make some for her birthday, and more for Christmas, and I frequently see her wearing them.
In addition, I ended up giving bracelets to my ex-girlfriend's sister in law, and one of my niece's friends, so I ended up making bracelets for six people, instead of just the three I intended.
Between the end of September and Christmas eve, I produced more than 30 bracelets, averaging at least one every three days.
That may sound like I was working very slowly, but one must keep in mind that I needed to open a new can of pea soup every time I wanted to make a new blank, and in spite of the fact I enjoy pea soup, I can only eat so much of it at a time!
But that leaves me in a bit of a quandry. My recycled HDPE bracelets were such a success that it leaves me wondering what I am going to make for next Christmas.