Styrofoam Gravestones

We decided to welcome our Halloween guests with a nice, quiet graveyard. Would you like to stay for a while?

Materials
Construction
Engraving
Painting
Installation
Inscriptions
More Details
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Materials

Foam

Our tombstones are made from expanded polystyrene (styrofoam) sheeting. This is available at builders' supply stores and lumber yards. It is used to insulate buildings.

There are several different kinds using white, blue, or pink foam (the latter two said to have a finer structure). Some have plastic or foil film on one side.

Colder regions of the country have a wider assortment of this material, because they need more insulation.

We got ours at Home Depot. In Southern California, I have only seen the white material, in 4'x8' sheets, in thicknesses of 1 and 2 inches.

You can get styrofoam in craft stores like Michaels, but I wouldn't recommend it. Tombstones take a lot of foam, and it is cheaper in bulk at the home stores.

Glue

We experimented with the use of expanding insulating foam in a can ("Great Stuff") as an adhesive. It worked well, and set rapidly, but had a tendency to push the pieces apart as it expanded.

We settled on Liquid Nails brand construction adhesive. They have numerous flavors. We picked the one designed for foam. This adhesive cures by drying out. Since most of the glue is trapped between plastic sheets, this take a long time. Allow at least a week for the glue to dry.

Joint Compound

Joint compound is also known as spackling compound or wallboard mud. It is available as a powder (to be mixed with water), or a pre-mixed mud-like paste.

Construction

Each tombstone is constructed of three layers of styrofoam sheeting. The yellow line in this "stone" is not actually a layer of styrofoam sheeting. It is expanding insulating foam used to glue this particular set together.

The base contains a piece of 2x4 wood. This gives it some bottom-heaviness. Sandwiched between the outer layers of plastic foam is an inner frame, constructed of PVC pipe.

[internal braces] The internal PVC frame is a standard part of our construction. They are glued into the 2x4s that form the bottom base. The 2x4 varies in length, since it runs the entire width of the tombstone.

Here are a number of frames, waiting to be embedded in tombstones. Note that two of them have tees in the top. From there, risers give structural stability to the more elaborate constructions, like the Celtic Cross.

The internal frame provides structural rigidity. It also provides a socket for the 18"rebar stakes that hold the tombstone up and straight.

[cutting the outline] We start by cutting the big sheets of foam board into more manageable pieces, roughly the size of the stones.

We did all the cutting with home-made foam-cutting tools.

Here, David works on our most elaborate piece: a Celtic Cross. This is the only instance where detailed cutting was done before assembly.

[pressing] The various layers are glued together and stacked up to dry. A weight on the stack keeps everything together until the glue dries.

After the sandwich is solidly glued together, it is time to trim the outside edge of the tombstone. Most of our stones had the traditional dome shape, although they were done in several sizes.

Engraving

The previous steps resulted in a solid, well-shaped tombstone. A blank tombstone. Now, it is time to personalize it.

We actually carve the inscription into the surface of the foam board. This provides a three-dimensional appearance and response to light that is clearly not just painted on.

[painting] Here's a closeup of the chiseled inscription after painting.

[engraving] The inscriptions were printed by computer on ordinary paper and then projected onto the blank stones. The projected image was traced with a marker for subsequent carving.

We used an inexpensive "Projecta Scope" opaque projector from Michael's. It worked well, but is limited to projecting images from only small material, roughly the size of an index card.

[engraving] A hot-wire cutter was used to follow the markings.

The V-shaped tip of the hot wire made a nice track, appearing both deep and chiseled.

Here, Dennis engraves the inscription for "Yule B. Next", an honored guest in our graveyard.

If you make a mistake and cut too far, or cut the wrong thing, don't panic and throw away the stone. You can use joint compound to fill in the mistake. It works pretty well, as this little story relates:

Our original carving of the "Yetta Nother" tombstone featured a small star of David, because "Yetta" sounded vaguely Jewish.
We debated whether anyone might consider this anti-Semitic. "Look - They're killing Jews!"
The argument for keeping the star was that we already had plenty of obvious Christian symbols: an elaborate Celtic Cross and a cross made from a crossed wrench and screwdriver. With no signs of Judaism present, it might look like we were discriminating against Jews by their absence. "Look - They left out the Jews!"
We eventually filled in the star, and you can't tell it was ever there.

This is a good time to remove any marks left on the foam from the opaque projector tracing that have not already been carved away. We didn't, and we regret it!

Most of the tracing was done with a red Sharpie marker. We figured that the paint would cover it. And it did ... at first. Then the red started to bleed through the latex paint, and come up to the surface. Rather than repaint all the stones, I dabbed the surface with some chlorine bleach. This got rid of the red stain, but while in storage for the next year, it bled through again.

Painting

Painting takes three passes.

[painting] The first pass, shown on the right of this photo, uses black latex house paint to get into the crevices of all the engraving. There is no need to be neat, because excess paint surrounding the inscription will soon be covered.

The second pass, shown on the left of this photo, is a quick roller job. It paints the bulk of the tombstone; covers excess black from the inscription, and "exposes" the artwork. It is important to use latex house paint for this step, too.

[painting] The final step uses black and white spray paint to speckle the stones, giving them a granite-like appearance. The latex undercoat prevents the spray enamel from eating away the styrofoam.

[painting] Here's a closeup of the faux granite finish.

Installation

The tombstones install by slipping them down over rebar stakes hammered into the ground. The stakes are made from rebar, cut to 18" lengths and painted with an orange safety blaze at one end.

[installation] We are midway through an installation, with all of the necessary tools evident: placement jig, hammer, stakes, and cola!