Based on a sacred heart pendant and unique display case she saw in Italy, my friend Stefanie asked me if I would consider making her a similar display case. After looking at a photograph of the display case she saw, I said, “Sure, that looks like a fun and interesting challenge!” Stefanie ordered a sacred heart pendant from a friend she made in Italy, and had it sent to me so I could size and design a display case around it.
As a practicing veterinarian, one of the special features that attracted Stefanie’s attention originally was a hand-drawn graphic of an anatomical human heart featured on the front of the display case. After an extensive search of stock photographs and illustrations, I acquired a full-color illustration very similar to the graphic on the original display case. The design challenge then became finding the best method of applying the illustration to our version of the wooden case. My friends Joanna and Vince at CG Vinyl Studio suggested inkjet printing the illustration on printable vinyl, overlaminating it for protection, attaching it to the display case with a special spray adhesive, and finally coating the entire piece with clear, two-part epoxy resin.
Next came the design challenge of tracing the outline of the display case and scaling it to Stefanie’s pendant. Once the tracings of both the display case and pendant were done in InkScape, I imported the vectors into SketchUp and designed a two-piece display case with a windowed display area and hidden recesses for storing the pendant’s chain. For ease of access, the two-piece case will be aligned with brass dowel pins and held together with four small magnetic catches.
From SketchUp, I exported the 2D vector outlines of all features on the front and back of the case into Vectric’s VCarve Desktop CNC design program and G code post processor. Since the front of the case had features that had to be machined on both surfaces, this project was my first use of VCarve’s two-sided machining capabilities. Once the CNC designs were complete and G code routines were generated for each machining step, I build an indexing jig for the CNC router’s table, so that blanks for the front and back of the case could be repeatably positioned. With all this preparation, and the CNC router’s working axes zeroed at the blanks’ lower left “0” corner, it was easy to complete all the machining steps with a quarter-inch solid carbide up cutting end mill.
After completing some sanding and other details of the wooden components, it’s time to turn attention to the vinyl graphic attachment and finishing techniques. A few test graphics have been printed and are awaiting the arrival of a cold laminator with which to apply the overlaminate. I will try some different materials and techniques for applying the graphic on some samples of maple before I tackle the real thing!
That’s the current state of this project. I will update with more explanation and photos as work progresses!
The original Sacred Heart Display Case
Stefanie’s pendant arrives from Italy
The sacred heart pendant is very detailed
SketchUp model of our display case design. (The colors are not yet finalized.)
Exploded view of our display case design. (The colors are not yet finalized.)
Hand flattening one of the maple blanks before planing to final thickness of just over one half inch each
Two maple blanks ready for some CNC work
Back of the front blank indexed to the jig
The CNC router zeroed at the lower left “0” corner
Cutting the large pocked in the back of the front blank
UCCNC control software sending the G code programming to the CNC router
The front of the front blank, with the window cut out. Three tabs keep the waste in place, to be cut out by hand
Milling the final outline of the front blank
Front of the back blank, with the large pocket milled
Cutting two circular pockets in the front of the back blank, for chain and other storage
Cutting the outline of the back
Back, complete, showing large and small pockets, and four magnetic catch locations
Back and front, with machining complete
Front and back, with a quick sand to remove fuzzies
Heart illustration, full color
Heart illustration, black and white
Heart illustration, muted colors
Heart illustration, sepia tone
Final sizing magnet catch washer pockets at the drill press
Flush fit with a Forstner bit
Magnet cup locations finalized
Cutting the polycarbonate window on the CNC router
Used the same profile as the large pocket in the maple front, offset slightly smaller
Polycarbonate window with protective film still in place, fit to pocket
Front view, with window temporarily in place
Back and front pieces, cut from the rectangular blanks
Making brass alignment pins from 1/8″ brass rod
Bullet nose shaped on brass alignment pin with a mill file, while spinning in the lathe
Closeup of brass pin with bullet nose
Mock up of magnet catches and alignment pin
Pad drilling alignment holes in back and front pieces
Sanding the edges of back and front pieces pinned together, on the oscillating drum sander
Laying out copies of the muted color heart illustration in InkScape
Inkjet printing heart illustrations on clear glossy vinyl
Vinyl heart illustrations for testing, printed on HP and Canon printers
Ready to apply 1.0 mil overlaminate with a Vevor cold laminator
The 1.0 mil overlaminate is super thin and difficult to handle
The cold laminator applied the overlaminate perfectly
Cutting out the finished vinyl graphics with a No. 11 blade and cutting mat
Painters tape and Tyvek on the bottom of maple samples for testing varnish and epoxy coatings
Using 3M Super 77 spray adhesive to affix a vinyl graphic sample with a pressure sensitive adhesive backing seems like overkill
Notes for various test pieces
The spray adhesive overspray leaves a textured surface around the applied graphic
Two maple samples to be coated with spar varnish prior to applying the vinyl graphics. The pencil marks are for practice aligning the graphic to the opening in the display case
Gram scale with 0.01 g resolution for mixing the two-part epoxy components by weight
Ready for epoxy coating a maple sample, prior to applying the vinyl graphic
Using enough epoxy to allow it to flow across the sample surface and self-level seems to be the key to a successful coating
The heat gun was ready to help eliminate any bubbles in the epoxy, but was not needed on this pour
Top portion of test graphic pealed back so the bottom edge can be used for alignment
Test graphic applied to maple sample with one coat of spar urethane and light sand at 320 grit. Pencil line is only for alignment practice
Test graphics applied to maple samples with one coat of spar urethane (L) and one coat of epoxy resin (R)
Ready to apply top coat of epoxy resin
Self-leveling dose of epoxy resin applied. Used foam brush to break surface tension at edges to allow epoxy resin to flow down the sides of the maple sample
Epoxy applied to graphic and maple sample with undercoat of spar urethane
Epoxy applied to graphic and maple sample with undercoat of epoxy resin. Note: Visible dark edges of test vinyl graphic are due to a bad trimming job on my part. I’ll do better on the final product!
Epoxy pouring setup, showing leveling board to allow even distribution of self-leveling epoxy resin
Locating the brass pin after having a custom silver jump ring fabricated by Jewelry Set In Stone
A plastic card with 1/8″ holes drilled in it used to protect the wood while cutting the brass pins with a small cutoff wheel in the Dremel tool
Dremel set up with the flexible extension
Brass pins flush on the back of the back
Sacred Heart pendant positioned in the display case
A layer of painter’s tape covered with a layer of Tyvek tape provides a releasable, impermeable barrier to the epoxy drips that cling to the bottom of the workpiece after the epoxy pour on the top surface
Trimming the mask with a No. 11 blade and cutting mat
Masking on the back of the front piece got a little involved
Front and back masked and ready for epoxy
First coat of epoxy on the back of the back shows a glass like surface
For the self-leveling epoxy to flow correctly, the workpiece has to be very level. A leveling board with adjustment screws in each corner works to fine tune the setup
Initial epoxy pour in the early stages of self-leveling
A foam brush is used to break the surface tension at the perimeters, so the epoxy will flow down the vertical sides
