# Making concrete tombstone molds?



## Stench (Aug 30, 2005)

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!


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## Runfromron (Aug 29, 2005)

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


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## Wolfman (Apr 15, 2004)

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.


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## Stench (Aug 30, 2005)

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.


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## Doug B (Oct 12, 2004)

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.


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## Scooty (Sep 1, 2005)

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.


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## Wolfman (Apr 15, 2004)

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.


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## FontGeek (May 7, 2005)

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!


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## NecroBones (Oct 1, 2005)

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.


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## mrklaw (Nov 2, 2005)

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


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## Stench (Aug 30, 2005)

Thanks for all the ideas!! I love the idea of using clay for epitaphs and cracks! I figured if I put 1/2 pvc for 80% of the stone, it would cut down on the amount of wire I'd need for reinforcement. I'm noodling about a seperate mold for a base or just leaving it as is. I figure it will take me several "recipes" of cement mixtures to get one that works well. I'll put up pictures as things progress. Any more ideas? Keep em coming!!

If the stones look authentic..I may well leave them up year round. My neighbors already think I'm nuts...give em something else to talk about!


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## Redneck220 (Dec 13, 2005)

*acvice from a concrete finisher*

I just joined the forum and saw the post on concrete tombstones and had to comment. Having been a concrete finisher for the past 18 years I can offer some insight.

#1. Head down to your local masonry supply house or concrete plant and inquire about "fiber mesh". Fiber mesh is short strands of a sort fiberglass that acts as a reinforcement like wire does. The manufacturer claims using it is as strong as using wire. I can tell you jack hammering fully cured concrete with fiber mesh in it is not an easy task sometimes. Wire and rebar always rust inside the concrete and eventually helps with its decay, since concrete is porous and allows moisture in it. Ever go by a highway project and see green rebar? The rebar has been coated with a special epoxy paint to thwart rusting. With fiber mesh you can get enough to do 10 cubic yards in a large ziplok bag, so storage isn't an issue, and it won't cut you like wire will. It also is mixed right into the concrete mix so there isn't any wire to poke through a spot where it got to close to the edge. 

#2 The vermiculite is an excellent idea to make the tombstones lighter!

#3 If you wish to use some of the epoxy coated wire or rebar you can usually get some short peices from a conrete contractor rather easily. One foot pieces and such are rather common laying around. Just go to a concrete supplier for a can of the epoxy spray paint to touch up the ends and any scratches that would allow rusting.


#4. Many places now have foam form materials to achieve the older style concrete forming withouth having to go through messing with wood as well. A good wood to use if doing a lot of concrete forming is a type of plywood called around here "ply-form" It's a special plywood for concrete forming that is impregnated with oil to prevent swelling of the wood and leaving large wood marks., It isn't cheap stuff, but I thought you might be interested to know.

#5. (enviormental people look away) In a pinch you can use old motor oil as a release agent as well sprayed or brushed on. It tends to stain so it may be advantageous to you. (no we don't use that anymore, we use special form release oils) and those special form relase oils----the same results can be acheieved with deisel.

#6 I like the using clay for a way to put "hand carved letters" into concrete. Will have to try that on one of my jobs.

#7 Hinge forms- iI am not sure what shapes you are going for but you can make "hinge forms" that could greatly make it easier to make your headstones. I'll use this for an example- IF you wanted to make a rectangle cut your pieces of wood and instead of nailing or screwing them together, fasten them with hinges that have removable pins. When you are ready to remove the forms, just pull the pin from one hinge,, and the rest can be folded out , and then re folded and pin attached for the next one. You will probably need to screw a piece of wood at an angle across the form to help hold it square until it sets enough. 

#8 Different dyes and powders can make for some interesting colors as others have suggested. Try some of the dye powders and sprinkle a thin line of it on the area that will be the face to obtain to possible "veins" as was suggested before. Not sure how this would turn out, as I have not tried it , but the idea sounds like it could work.

#9 I can't think of anything more at the moment except a word of caution. Remember that concrete contains caustic materials. While they are not extremely dangerous, the dust for one is very bad to inhale, so if in mixing you are creating a lot of dust use a dust mask. Concrete burn is also something to avoid. So remember to wash it off your skin promptly. 


Hope i didnt overload! 

Mike


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## Annea (Aug 14, 2004)

We used ply wood forms to give curved edges to concrete, it worked quite well.


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## FontGeek (May 7, 2005)

Come up with a formula as far as spacing for the PVC pipe so that you can use a constant spacing settup for the rebar or supports that go into the ground. As for having the base and the stone as all one piece, I would pprobably go with seperate pieces, that is how most of the actual monument style stones that I have seen were done, from your end of it, having seperate pieces keeps them lighter in weight, easier to move, and if you break a stone or base, you haven't lost the whole thing, you can replace or repair the part that is broken.
I would also put an eye-bolt sticking out of the back of the stones, this would give you a way to lock them down, whether you have a problem with vandals or thieves or not, I don't know, but the bolts help give you a way to tie the stones down against the tipping, theft, etc.

A question for those who have used the vermiculite in cement before, does this stand up over time or moving the stones in and out of storage, settup, etc.?
I know that a lot of gardeners add it into the soil to help keep the soil workable, but it breaks down in the soil. If it started breaking down while in the concrete, wouldn't that be a problem for structural integrety in the stones them selves?
Just curious.


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## Annea (Aug 14, 2004)

Have yu ever tried a lime mortar, it gives a good colour and texture, although can be difficult to handle.


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## FontGeek (May 7, 2005)

Annea, how is the lime mortar for curing when it is in larger or thicker pieces, like a tombstone?
Is it brittle or fragile on it's own, or does it need reinforcement (wire, rebar, etc.)?
Could it be used with concrete, maybe a thin layer layed into the molds first, then filling the balance with concrete, pvc, etc.?


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## Wolfman (Apr 15, 2004)

You can get an exposed aggregate effect by mixing brown sugar in water. Use a lot of sugar. After your form is filled, brush the mixture onto the surface. The next day you can wash off the slurry to reveal sand and stones just below the surface. It will look weather-worn.


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## Redneck220 (Dec 13, 2005)

*sugar and concrete don't mix!*

just to make you aware,,, don't mix the sugar mixture INTO the mix. Using it on the outside to create the worn finish is ok. Sugar chemically reacts in masonry and slows down the curing process and weakens it. Thats why using it on the outside is good for creating an exposed aggregate look.

Some concrete crews I've heard will dump a 2 litre bottle of coke into the drum of a concrete truck before pouring to "slow down" the curing process. If you were to pour sugar on wet cement on a corner of a sidewalk, the spot where the sugar layed would stay wet long after the rest of the concrete is hard. Sugar chemically retards the concrete and greatly weakens it by not allowing the curing process to take place as it should. So back to our crew up top and thier bottle of soda. In essence they are making the concrete weaker by upsetting the curing process. The soda isn't a huge amount and the concrete will harden in time, but it will be much weaker. 


something fun to try---Take a cup of coffee (black coffee will show best, no cream and sugar) and pour some onto wet concrete. the concrete on top will turn green. I have no knowledge if it adversly affects the strength, but try pouring it on the wet concrete to stain the surface some.


Mike G


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