Stefanie’s Sacred Heart Display Case

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. The modified heart graphic was printed on glossy inkjet-printable clear vinyl and a protective overlaminate film was added with a cold laminator. The inside surfaces of the back and front of the display case were masked with a layer of releaseable painter’s tape and a layer of nonporous Tyvek tape in preparation for coating with two coats of clear two-part epoxy. Once the first coat of epoxy was cured, the vinyl heart graphic was cut out with a fresh No. 11 blade and applied to the front of the display case. A second coat of epoxy embedded the graphic, rendering the clear areas nearly invisible. Two coats of spar urethane on the inside surfaces of the display case were applied and allowed to dry thoroughly.

Cherry was selected to use in fabricating a desktop stand for the display case. A quick design in SketchUp and VCarve Desktop provided the data to build from. Two coats of spar urethane deepened the reddish hues of the cherry in a nice contrast to the light maple of the display case itself.

After magnets were epoxied in and the polycarbonate window was affixed with silicone, the last step was to flock the display case cavities and saddle of the display stand. Black Suede-Tex flocking was applied to the wet black adhesive with a very fancy (two cardboard tubes) Mini Flocker.

Based on sliding the magnets apart instead of pulling on them, opening and closing the display case is easy, but not obvious. I created this short YouTube video to provide a few tips:

This was a fun and challenging project that provided the opportunity to learn some new techniques and to buy a few new pieces of equipment. Thanks again, Stefanie, for allowing me to collaborate with you on this unique display case!

Here is a pictorial record of the project. Each picture is captioned with information about the step it represents.

: 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

: UCCNC control software sending the G code programming to the CNC router

: Cutting the large pocked in the back of the front blank

: 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

: Closeup of brass pin with bullet nose

: Bullet nose shaped on brass alignment pin with a mill file, while spinning in the lathe

: 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

: Mock up of magnet catches and alignment pin

: 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

: Ready for epoxy coating a maple sample, prior to applying the vinyl graphic

: Gram scale with 0.01 g resolution for mixing the two-part epoxy components by weight

: 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