Thread: Making concrete tombstone molds?

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Does anyone have tips or ideas in making concrete tombstone molds? I've seen the nice molds on ebay and such for plaster or concrete, but I'm going for realism..not so much cartoonish. I'm trying to figure out a way to have two or three basic molds (probably out of wood) about an inch and half thick and small enough to be manageable, but large enough to be impressive. If I could change the names and dates buy putting in a foam insert it would be great!! I'm planning on casting about 50 stones this winter if possible!

Well, Stench, you don't seem to be getting many hits, so I'll toss in my two cents worth...

I'd use a sheet of plywood for the BASE of the form, but I'd use 1-1/2" X 1/8" strap metal for the actual forms on top of the plywood. Bend the strap to the shape you want (draw it out on the plywood so you can test it as you go), and use 1" X 2" wood blocks on the outside of the form to hold the metal in place. I'd use either chicken wire or old 1" X 2" fencing for reinforcement to keep the 'stones from cracking. If you want a 'texture' in the stones themselves, just put whatever you choose on the bottom of the form, and the concrete will make a 'negative' of the texture.

Concrete is a really good idea--cheap, long-lasting, easy to work (once you have the forms), and authentic looking. The drawback would be weight (of course), but just don't store them in the rafters of the garage and you should be O.K.

Good luck! Let us know how you fare....

Ron

Stench:
Full marks for authenticity BUT - Concrete weighs 150 lbs./cubic foot. Do you really want to "go there"? Mass concrete (unreinforced) is brittle, believe it or not, you'll need to use mesh reinforcing. With reinforcing it can crack, but it won't break. On the plus side - you can color concrete using pigments. I have benches and tables outside right now cast from colored concrete. People mistake them for polished granite. Green is especially attractive, it resembles jade.

I use styrofoam tombstones with a cement wash finish. I augment the appearance using a bit of black sand and some pigment. You'd swear they were the real thing...until you go to lift them.

Thanks for the replies...I've got a two acre field below my house that I'd like to make into a haunted trail, complete with "old forgotten cemetary".... I've made about 20 styrofoam stones, but really want the tots to walk thru the cemetary and be able to touch and feel the stones. I would not store these inside...probably leave them in a corner of the field. I'm seriously planning on 50+ stones. Styrofoam stones would work as "filler"...maybe have only 10 concrete stones. Epitaphs are not as important, but would like to make it as authentic as possible. Thought about using plywood as a base as you suggested, Ron..but placing foam or wood letters in the bottom to make a negative impression as the epitaph. Strap metal would be handy to make the bends. I've though about using cove or other wood moldings in the form to make a more fanciful design.

I used clay rolled into snakes to form letters for my “small” concrete tombstones.
After the concrete is set I used a hose nozzle to wash the clay out.
The result is a more hand worked letter as opposed to a machine made letter.
You can also make surface cracks and defects with the clay.
I used the hose (by accident) on a partially set stone and it makes a neat weathered look, rounding off the hard edges.
Also is tried some of the concrete dyes, red and black.
I liked the look and you can alter the amount of dye to get a different shade for each stone.
Keep the dye off your hands!

For the wood molds you will need to fill the wood grain to keep it from transferring to the concrete.
Real cheap Pam makes a great mold release that doesn’t need to be cleaned off.

Hope that helps.

What would a person use for a mold release? Could you just use some Crisco or something and then powerwash it clean a week or so after you removed it from the mold? Have you thought about putting some PVC "sleeves" inside of the concrete so you could slide the tombstone down over rebar that was hammered into the ground?

Leaving the stoned outside to weather would enhance them. If I were to tackle this project, I would get some hog panels from the farm store and clip concrete reinforcement from the steel mash panels in a shape slightly smaller than the mold pattern. A pair of boltcutters will snip right through 3/16" steel rod. As long as the concrete held together for safety reasons, I would welcome cracks and chips in the concrete to make the stones look older than they really are.

A side note...my son and I recently helped repair some vandalized tombstones for an Eagle scout project. The stones were a minimum of 100 years old. Most had a rectangular base and the taller vertical stone with the epitaph was attached with metal pins that slid into holes that were drilled into each stone surface (2 pins).

Keep us posted with your progress.

The best releasing agent I have ever come across in over 30 years in construction is Thompson's Water Seal. The form will literally pop off of the concrete. And the form will be pefectly clean for re-use. Awesome stuff.

In addition to the information already given, I would add a few things to the thought process.
Masons and concrete people often use rock salt to give the pitted finish, for your stones, just toss some in the mold before you pour the concrete.
Look at the way cake and jello molds are designed, the walls of the molds are slightly slanted so that you can pop the cakes or jello out. The same line of logic applies here for the stones.
Besides adding rebar or wire mesh for strength, I would also add at least two pieces of PVC pipe into each stone, with one end plugged, and the other end temporarely plugged and flush with the bottom of the stone. These give you a way to stand your stone up. By using pipe large enough to slide rebar into, it gives you an easy and predictable way to guaranty that the stones are not going to casually tip over, and with the weight as Wolfman mentioned, having those tip when you have TOTs roaming around is an injury and lawsuit just looking for a place to happen.
If you are going to make a lot of stones the same shape and detail, then having a heavy duty mold will be worh the effort. There is a material called Dragon Skin that is a silicon based gel, it holds incredible detail, and can stretch so that having a skull with an open mouth, an angel with wings, etc. would not be very difficult to reproduce. However, it does mean that you would have to create one original to make the mold from. Once that is done, all you would need is the mold and a basic form that would keep the Dragon Skin mold from stretching out of shape when you pour the cement in. You could still do the same tricks with the clay or plasticine for the lettering or epitaphs if you wanted to change them from stone to stone. You can also use the brass or wooden lettering used for numbering houses or for signage.

I think the tinting of the cement is a great idea. If you can mix tinted and un-tinted in the mold at the time of pouring, you might be able to get some veins in the stones, as you would in granite, marble, etc.

Whatever you do, take pictures and notes, we want to see the whole process you go through, the good, bad and the ugly. I will be curious to hear/see what the final recipe is.
Good luck!

Actually, if you line up a whole bunch of PVC pipes inside the gravestone, you'll also reduce the amount of concrete, and thus make it a little lighter for transport . So the pipes will be functional for rebar, and also help reduce mass.

You might want to mix perlite or vermiculite into the cement instead of gravel. That would make the stone a lot lighter, but it would still have the feel of concrete. This is commonly done for roofing and places where better insulation is needed.

I've read that it takes a little longer to set than if you use gravel so you might want to leave it in the mold a little longer.

check out this link
http://www.schundler.com/vermcon.htm
http://www.strongseal.com/html/ltwt_concrete.php