Recycled HDPE Plastic Logo (Without a 3D Printer)

In the pursuit to build up my personal [garage] shop, I have amassed a respectable amount of tools without breaking the bank. I wanted to create a personal 3D [Kozi] logo without using a 3D printer. I realize that a 3D printer would negate a lot of the "work," however, I wanted this to be done using recycled HDPE and act as a general skill building exercise using different tools to produce a product.

My intention for this Instructable is to show makers, creators, etc., that there are a lot of usable materials out there such as HDPE that could be formed into make logos, trinkets, signs, cutting boards, and whatever else your mind thinks of.

Another thing is that even though I use power tools for this, the same could be accomplished with various hand tools.

HDPE plastic to reuse / re-melt

Paper / printer, to transfer the logo or picture

Liquid sticky, I used adhesive spray

Cutting tool(s), I used my restored bandsaw and scroll saw (but you could use a hacksaw / coping saw)

Drill, to get into the inside portions

Files & blades, I used a modified sewing machine and a knife

Sanding tool(s), I used a disk sander (but hand sanding is cool, too)

Paint (optional, especially since adhesion to HDPE is rough...)

I collected a ton of HDPE bottle caps during COVID. When folks were able return to work after quarantine, we were not allowed to use the communal water fountains and there were a lot of water bottles. The #1 PET plastic bottles generally get recycled everywhere in my area but HDPE recycling depends and is dicey depending on where you live. So with that in mind, I saved my caps and the rings, too (pic 1).

In order to flatten my melted plastic blob into a blank (pic 2), I made a plastic press using a hydraulic jack and scrap materials. I have another Instructable on that build as well as other dealing with melting and reusing HDPE. I would appreciate it if you gave those other Instructables a look!

Now that I had a flat piece of stock to work with, I used adhesive spray to glue on my logo (pic 3).

I used my Delta bandsaw to remove all of the outside excess (pic 1). I saved all the scrap for future melts to reuse again in the future. That is the beauty of reusing HDPE, as long as you don't burn it, you can reuse (re-melt) it again for later use, including those that have already been melted.

I used a 1/4-inch blade on the bandsaw to get into the nooks and crannies. I also used the "back of the blade" trick for finer work on the edges. This is especially handy when working fine points like the trailing bottom edge of the K (pic 2 and 3).

In order to get into the inside portions, I drilled a few holes to allow my scroll saw blade to fit into (pic 1). Moving this around and taking my time gets rid of all the excess on the inside portions of the logo (pics 2 - 4).

I couldn't get into the O inside part with the scroll saw blade since it was so small. In order to do that I had to go back with a smaller drill bit and make a couple of holes. Afterwards, I cleaned it up with some small hand files.

With the bulk of the material removed, my logo is starting to look like … a logo.

I took the long outside edges to the disk sander to clean them up & for the inside portions, that is a different story.

I bought an old sewing machine at auction for ~$4 USD but the problem was that all the moving shafts for the bobbin (the parts underneath the machine) were removed. Then I realized the person before me made it into a make-shift scroll saw. Having already restored one (as seen in the previous step) I thought about how to repurpose this already repurposed machine. It hit me that I could potentially fit in some small files similar to the scroll saw blade. I bought the smallest hand files I could find at Harbor Freight and took them to the angle grinder for modification.

These fit where the needle normally goes (see pic 3) and makes quick work of filing the finer details, inside and outside of the logo letters!

Obviously, you could simply hand file it yourself unless you know of someone getting rid of a old sewing machine :)

I removed all the paper thinking that it would wear off eventually anyway. I threw a couple coats of acrylic paint on it and called it a day.

NOTE on HDPE painting: this paint does not stick very well to HDPE. In fact, a lot of different paint mediums may not adhere. I tried using the trick from The Crafsman on YT where they anneal the plastic before applying the paint and didn't really notice a difference in adhesion. I could easily scratch off the paint like a lotto ticket even after heat treating.

If you know of a better method of painting HDPE, please leave a comment because I would like to add a pop of color to colorless HDPE such as these bottle caps or milk jugs.

Here is a video of my process which includes a voiceover.

Thanks for checking out my Instructable and I hope this inspires you to create your own logo or sign or something similar!