I’ve been making some heart bowls for
a while and I thought I’d extend upon that concept and turn it into a jewelry box. I started a fresh new project
in Fusion 360 and designed a more organic shape with my signature
epoxy line going through the middle. I figured this would be easy to
make, but I had several problems I encountered and had to solve along the
way, including breaking an expensive bit! My normal process is to glue up several pieces
of cherry wood until it is precisely 2.5” thick for the box. I could then machine the epoxy mold
directly into the wood. I generally use a spiral downcutting bit to get a good finish on the
bottom of the workpiece and avoid chip out. The bumpy pattern in the wood is what leaves
the drippy-like look in the finished box.
I repeated the process using a
3/4” piece of wood for the lid. My shop is pretty cold, around 58F, so I
pre-warmed the epoxy in some 80F water and used a space heater on a temp switch to keep
the workpiece warm while the epoxy cured. Epoxy likes to cure at around 70 to 75F. The first epoxy step was to seal the wood
with a thin coat of quick setting epoxy. I mixed up and tinted the epoxy,
poured it into the wood area, and let most of it drain out.
I even used a
heat gun to help the epoxy flow a little faster. I did this in order to not have layers
show up in the finished workpiece. However, I don’t think it is always necessary to
seal the wood and I stopped doing it in some later pieces. Specifically, less porous hardwoods
that are fully dry don’t need to be sealed. The main epoxy pour was with a deep pour epoxy, and I tinted it Bora Bora Blue
from Black Diamond Pigments. I generally overpower the piece a bit, and
use some silicon sealant to keep it all in. Once the epoxy cured I could plane it
back down to the original 2.5” height. Then it was back to the CNC machine where I used
the blue tape and CA glue technique to hold down the workpiece.
This was required so I could access
the entire workpiece without hitting a clamp. I machined the outside of the
box, and popped it off the table. Notice that the glue is what separated
when I pulled the two pieces apart, instead of the tape ripping apart. I tested
this with the lid before I machined it, and the same thing happened. This is
foreshadowing an upcoming problem. I machined the lid in the same way as the box
bottom, but I decided to to the inside of the lid first. This also had some issues due to
my tool paths, which will come up in shortly. I realized that my general CA glueing process was
flawed. It would work sometimes, but not all the time. I’d put a bunch of glue on the workpiece,
use some accelerator on the other side, and squish them together by hand for a few seconds.
I’d also
toss on a heavy weight to help hold it together. My CA glue was probably a few years
old, and it really only has a shelf life of one year. But the problem is the glue
skinning up before it adheres to the part. I’ll show how I solved this in a
short bit…but first the big problem. I glued the workpiece to a scrap piece of plywood
in order to indicate in the origin of the box. This alignment is critical for getting the second operation to precisely match
up to the first operation. Once I started machining the
workpiece it started chattering a TON. I stopped the machine, grabbed the
piece, and it popped off in my hands! I decided to temporarily solve this
problem by using some 5 minute epoxy. I let it cure for a full hour and
then proceeded with the machining. The alignment was off a
bit, but it wasn’t too bad! My solution for the CA glue problem was to clamp
the pieces and let the CA glue cure for 5 minutes. Once I started this, the glue was no
longer the failure point, and the tape would rip away.
It was MUCH stronger, and
I think it entirely solved my problem. I used this new CA glue and tape method to attach the lid to a scrap piece of
wood, and indicated it in. On one box I put it on my table, and on another
I put it in a vice. Both techniques worked fine. Once I had finished all the machining I
test fit the lid. This was my next issue; the lid was way too tight, probably
because I didn’t design in any tolerance. The solution for my prototype piece was to just
grind away the lip on the lid. This worked, and I could sand out any alignment
issues on the entire piece. When I did a second box, I decided to
inset the lid by about 0.025 thou to get it to fit better, and this worked pretty well. I really like using Osmo Top Oil for my
bowls and boxes. It is super easy to apply, fairly durable, and leaves a nice satin finish. My prototype box turned out awesome! However, there is always room for improvement,
so I decided to lighten the lid a bit more, make the grip a bit bigger, and the walls of
the box a bit thinner to make it more petite.
The second one was made out of
cherry with purple tinted epoxy. If you want to learn how to make these,
then consider buying my complete guide on how to make the heart bowl – the link is in the
description. I include the Fusion 360 file with all my machining tool paths, along with some
STL exports for people who don’t use Fusion. I also have a step-by-step PDF on how to make it. Comment below if you want me to release the Heart
Box for you to make on your own CNC machine!