• Materials
  • What Glue To Use?
  • What Color Foam?
• Procedures
  • Internal Frame
  • Peeling Foam Skin
  • Trim To Size
  • Rounded Edges
  • Filling With Joint Compound
  • Sanding
  • Cutting Cracks
  • Faux Granite Finish
  • Painting Dirt
  • Painting Moss
• Aesthetics
  • How Big Are They?
  • What Shape To Make Them?
  • Spooking Up
• Maintenance
  • Repainting

• Related Pages

3M "Super 77"

For one tombstone, Dennis laid the adhesive on thick. After trying that, we used a lot less on subsequent stones.

We like this adhesive mostly because you get nearly instant satisfaction, with no lengthy wait for the glue to dry. It also cuts well with the hot knife - especially if you use just a little.

We have settled on the following application technique:

• Make sure both surfaces to glue together are clean and dry.
• Spray one side, fanning the spray side to side.
  • You can see the spray going out of the nozzle, but it disapperas as it hits the surface.
  • If you cen see a film of glue on the surface, you are using too much!
• Spray again, fanning the spray up and down.
• Spray other surface, side to side.
• Spray again, up and down.
• Wait at least 1 minute for the solvent to evaporate.
• Put the two parts together.
  • The bond is instant and very strong. You can't afford to put the pieces together wrong!
  • If necessary, get a helper to position everything correctly.
• Press the pieces together firmly.

My first experiment used a visible film of glue on each side, creating bubbles in places. Using so much glue did make a stronger bond. But a thin layer is plenty strong enough, and more economical.

Warning: If you spray Super 77 directly on unprotected foam, from very close, the solvents in the glue can melt the foam. Spraying from a distance of about 6" does not seem to eat into the foam.

Glue Comparison

• "Great Stuff" expanding foam

  Take care to spread a thin layer over one surface to be glued. You don't want lumps and gobs of the stuff. Perhaps a "rake" made from a piece of cardboard with notches in it would work well as a spreader.

  If you have big lumps, the spray foam will expand more there, and may push the pieces apart.

  The foam is somewhat slippery for a while, so you can nudge the foam around a little until it is exactly like you want it.

  Then weigh it down, so things don't move around!

  Benefits:

  • Expanding foam makes a strong bond between foam layers.
  • One very nice feature is that the expanding foam reacts to the hot-wire cutters the same way as the sheet material being glued together.

  Drawbacks:

  • Once you start dispensing from a can, the can of foam doesn't store well. Use it all now, or plan to throw it away. If you are planning to do a lot of stuff with foam, its use as an adhesive can be a bonus.
  • This stuff is famously messy. If you get any on your clothes or body, it won't come off.

• Liquid Nails (For Projects and Foamboard)

  There are several different flavors of Liquid Nails. We used the tube on the top "For Projects and Foamboard".
  

  First, make sure that you get the kind that is safe to use on foam. If you use a formulation made with solvents, it will melt the foam.

  Take care to spread a thin layer over one surface to be glued. You don't want lumps and gobs of the stuff. Perhaps a "rake" made from a piece of cardboard with notches in it would work well as a spreader.

  This material slightly resists cutting with the hot wire. Places that are thick with this form of glue will cut unevenly.

  Benefits:

  • Washes up with water.
  • Inexpensive.

  Drawbacks:

  • Takes a long time to dry.
  • Foam joined with this glue cuts unevenly when you hit a thick spot of glue.

• 3M "Super 77"

  
  

  Benefits:

  • Instant gratification.

  Drawbacks:

  • Very expensive, over $8 per can (October 2004), but a little goes a long way.
  • Can be messy if you use too much, or get it on yourself.

So, the question is: Do you leave the film on there, or peel it off?

To answer this question, we explored:

• Did the film, or absence of, it hamper construction?

  The film reacts to the hot wire cutter similar to the way that the foam does. So leaving the film on interior surfaces and exterior surfaces is no problem when cutting. Foam with and without film cuts equally well with a razor.

  The film is a bit of a problem when sanding the edges. The foam sanded rapidly, like a very soft wood, but the film took on a feathery edge (which is annoying, but mostly covered by the paint).

• Did the film or absence of it affect quality of the product?

  Tombstones made with and without film on interior and exterior surfaces looked equally good. Paint adhered slightly better without film, but this is only noticed when the tombstones are bashed around. Bonds between foam layers were equally strong with and without film. The results were virtually identical.

• Did the film or absence of it affect aging of the tombstones?

  All of the stones aged fairly well. There was some flaking of paint from sharp exterior edges, which was a little more obvious on stones with film.

  Film on 6-year-old tombstones peeled up as easily as film on new foam sheets (but you lose the layer of paint over the foam).

  For Halloween 2002, we sprayed hot glue webs around the graveyard. In most places, they came off with no problems, but in some places, they pulled a bit of paint off tombstones. I suspect that the stones most damaged this way had paint over film.

• Did the film or absence of it affect maintaining and repairing the stones?

  When we went back to some old stones and smoothed the edges, we ran into the feathered edge from sanding. This is a minor annoyance.

• If a tombstone was built with film on an exterior surface, and it was causing no problems, leave it. It's not worth the effort to peel off the film and repaint the whole tombstone.
• When building new tombstones:
  • For interior surfaces, peel off the film after cutting the rough shapes and before gluing them together.
  • For exterior surfaces, peel off the film after you are done carving the inscriptions.
• If you start peeling up foam, and find loose foam beads underneath, the foam sheet is bad quality. You can salvage the foam by leaving the film in place.

This poorly-made sheet of foam had a patch where the styrofoam beads were loose, and not tightly bonded together.

When trimming with our hot-wire cutter, a small bowl can be used as a guide for rounded corners.

Rounded Edges

This picture looks down on two tombstones from the top.

• The tombstone on the right shows a sharp edge.
• The stone on the left shows a more desirable rounded edge.

A rounded edge can be accomplished by sanding.

We chose instead to do most of the work with a hot-wire cutter that imparts a rounded edge. You just slide it over the edge, and it rounds it off.

You might want to do a little sanding to clean it up.

We now suggest that you:

• use as little joint compound as possible
• use joint compound as seldom as possible
• use the joint compound after all carving and shaping is complete

Joint compound seldom goes on smooth. You smear it on, wait for it to dry, and sand away the excess. The more that you put on, the more that you will have to sand off.

The biggest problem with joint compound is that it doesn't react to the hot wire cutter the same way the foam does. You can be zipping along, making a cut with the hot wire, hit a patch of joint compound, and stop dead - or worse yet, get pushed out of the way and make a crooked cut.

Tip: After putting joint compound on with a putty knife, wet your hands with water and smooth over the surface. The better the surface you put on, the less you have to take off.

We did all our sanding by hand, using a sanding block. We suspect that a power sander would be overkill.

As to the type of sandpaper to use:

• 100-grit works well
• 60-grit was tearing up the foam a little
• it might be nice to try 80-grit

David holds the hot-wire cutter that was used to engrave a crack in the front of a tombstone.

We started by dabbing dark latex paint underneath cuts and top surfaces - the places where dirt might collect.

We did some with a very dark green (almost black). Others we did with dark brown.

When sprayed with water, the paint runs and drips.

Spray until the obvious dabs look more like natural drips.

If you spray away too much paint, dab it on again. If the paint is too obvious, spray some more.

If you really mess up, wash the whole thing off with a hose and start again.

Dennis works on the 2004 gravestone for Nikola Tesla.

Note that dirt may collect on the top of the gravestone.

Here is a completed stone, made to look old, dirty, and weathered.

Sea sponge has a nice texture that is somewhat random and organic.

This one came from the paint department of Wal-Mart.

We prepared a flat pan with gray-green latex paint. Dip the sponge in the paint. Stamp the texture on the stone.

We decided that most of the moss should go on the right side of the tombstone, perhaps with a little more towards the bottom.

You can also stamp a little moss on other areas of the stone to hide imprefections!

One thing that we learned is that the sharp edges where two surfaces come together is a bad thing. That's where most of the old stones have paint chipping off. I suspect that's because the corners are (a) more exposed to being hit and (b) are less able to spread the force of an impact to adjacent material (sharp corners concentrate the force when you accidently bump something). We actually went back and rounded the edges of some of our old stones, even though that meant we would have to repaint.

This photo shows part of the front of two tombstones.

• The gentle curve of the stone on the left is preferred.
• The sharper angle of the stone on the right is less desirable.

This picture looks down on two tombstones from the top.

• The tombstone on the right shows a sharp edge.
• The stone on the left shows a more desirable rounded edge.

Note that a rounded edge can be accomplished by sanding. We chose instead to do most of the work with a hot-wire cutter that imparts a rounded edge.

• A few spots on the front had paint pulled off.
• A few spots on the sharp edges had paint chipped off.
• We used a new hot-wire tool to reshape the edges of some stones, and carve borders around the front.
• On a couple of tombstones, we peeled up the old film, losing the original pain in the process.

So, what approach to take? Do we repaint the whole tombstone, or just the necessary areas? Do we try to reprodice the old speckled granite finish?

We decided that the original specked finish is nice, and probably helps give a real stone appearance to stones viewed up close, during the daytime. But nobody gets closer than about 6 feet to our tombstones. At this time, there is no need to expend time and effort to do speckle broad new surfaces. Besides, if you can see the speckles, having some stones with and some without adds variety.

We also decided that small blemishes should not be repaired too well, as they help give a spooky look. We decided that small places that exposed white foam should be dabbed with gray paint to get them close to the surrounding color, and them dabbed with moss or dirt colors.

• Gravestone overview
• Gravestone details [this page]
• Gravestones update
• Additional Styrofoam Gravestones for 2004
• Inscriptions

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