Introduction: Tree Silhouette Bracelet

By Ossum
About: Electrical Engineer by trade, tinkerer by heart.

Introduction

In this project I wanted to challenge myself to make a piece of jewelry that someone who wasn't a 3D printing nerd might actually want to wear. This was a double challenge for me because

  1. 3D printed things usually end up looking cheap an plastic
  2. I don't have a stylish bone in my body

Weirdly it seems that I achieved both goals, because my wife actually wears it, of her own free will!

What you need

  1. STL files from Myminifactory
  2. ABS filament (I used Rigid.ink silver ABS)
  3. Acetone
  4. Big Jar
  5. Paper Towel
  6. Sharp Tweezers (for removing support material)
  7. A carrot and toothpicks, or equivalent tool ;-)
  8. Sand paper (100 and/or 200 grit should be fine)

If you make it

Please consider sharing photos of your prints and following me at myminifactory if you like what I do, or tipping me there if you REALLY like what I do.

Check out my Facebook page and Facebook group or my Instagram if that's your jam.

Step 1: Printing

Material

I believe that this is a rare project where ABS will be unmatched, I chose rigid.ink silver ABS since it prints beautifully and has a nice sparkle.

Advantages of ABS

  1. Supports come off easily
  2. Can be smoothed with acetone vapor
    1. Makes it prettier
    2. Makes it stronger by creating a contiguous skin (important on the branches)

Regarding PETG

  1. Could be very pretty
  2. Would be strong enough but...
  3. Would be hard to avoid strings and blobs around branches

Regarding PLA

  1. Too brittle, don't do it...
  2. or do do it and prove me wrong!

Detail Level

I printed at 0.1mm layers, but it really isn't necessary, 0.2 would probably be just fine.

Support

This model definitely needs support in between some of the branches of the tree. These will be a nuisance to remove but there is no getting around it. Remove them slowly with tweezers, the piece may still be delicate at this point (much stronger after smoothing).

Brim

This is up to you, but I chose to use a brim because the surface that contacts the bed is very small (and a brim like this is a moment's work to remove)

Step 2: Finishing

This is the step that really makes the project shine (chuckle).

Sanding

I started by doing a (very) quick sanding at with 100 grit paper, I should have followed it with 200, but alas. The smoother you get in this step the better, and it is an easy shape to sand, so don't be impatient like me.

Acetone Smoothing

Theory

There is a good article on this process here, but here is all you really need to know.

Acetone is a solvent of ABS, which means that if you leave ABS it it it will eventually dissolve completely.

Fortunately, acetone also has an extremely low vapor and boiling point, which means that if you put some in the bottom of a jar, close it up and leave it in the sun it will fill up with acetone vapor.

This acetone vapor will very slowly dissolve the surface of any ABS part you place in the jar, which results, eventually, in a smooth surface (it will also eat away at very fine details, so be cautious). An added benefit is that when the surface hardens again you will have an extra strong bond between layers, since it forms one solid skin.

Procedure

  1. Place some paper towel in the bottom of the jar
  2. Pour in some acetone (I made it about 5mm deep at the bottom of the jar)
  3. Suspend the item in the jar (see photos, I used a carrot and tooth picks) remembering that anything that is touching the item will be likely to get stuck into its surface.
  4. Set a timer. Very important or you will forget and come back to a blob of goo. I start with 30 minutes and go from there. Since it was a cold night when I did this it took about 2-3 hours, but I have had much faster reactions in the sun.
  5. Make sure you have a way to get the item out of the jar without touching it, since the surface will be tacky and be spoiled if you (or anything else) touch it is solidifying
  6. Give at least 30 minutes before you touch it. Always test on the inside where it won't be visible if you mess up the surface.

Warning

Acetone vapor is also extremely flammable, never use it around an open flame. It should go without saying, but never try and warm it over a gas cooker or similar!

Acetone is not the nastiest of chemicals, but it is still worth reading the warning labels, take responsibility for yourself!

Homemade Gifts Contest 2017

Runner Up in the
Homemade Gifts Contest 2017

Epilog Challenge 9

Participated in the
Epilog Challenge 9