Make a Fossilized Dinosaur Egg




About: Eldest of five, son of two doctors, 10 years in Graphic Design and marketing, then retrained as a Biomedical Materials Engineer, don't ask me why, I think it was because I had always wanted to design artific...
Using one bottle cap and some oven bake modeling clay you can make a really realistic looking Fossil model. Maybe it's a dinosaur fossil or maybe it's a dragon fossil, who knows. All I know that until you start making them these things were amongst the rarest things in the world.

if you do it right you also get to do a little bit of fossil hunting as you chip away at the various layers.

A really quick fun little project to do just before the end of the holidays.

What you will need:

  • one round ended personal care bottle or aerosol cap
  • some oven bake modeling clay (Sculpy or Fimo) in any colour
  • Some tile grout or plaster or other mix-up paste filler that sets
  • scissors, marker, different coloured paints (spray)
  • glue gun (not essential but helps it go along nice and quickly)

Step 1: Mark and Then Cut Up the Bottle Cap Lid

Loads of personal care products have soft plastic (usually poly-propylene) caps with rounded ends. For this project you need at least one. Although if you want to make a whole fossilised nest, then you will need more.

First mark the cap by drawing a line that divides it in half vertically over the top, then mark two smaller divisions, one for each half. Try and make sure that these are the same size as each other, although you will be able to trim to match later.

If you have a nice soft reasonably thin walled cap, then you should be able to cut it out using strong scissors. If it is thicker and tougher you may need to use a fret saw. Don't use a craft knife, the cap is very hard to hold (slippery and squashy and a knife is not the right thing to use to cut it).

Step 2: Cut Out Some Cardboard

Position the pieces on a piece of thick cardboard and mark out an irregular shape round them.

Cut out this shape.

Straight away you can see the fossil egg shape.

If you want you can almost stop here, glue the bits down, spray them up and you're done. Nearly all fossilized dinosaur nests had eggs in that looked a bit like this with no embryos. but there are one or two very rare examples of fossil eggs with dinosaur embryos still in them, so continue to see how to make one of them.

Step 3: Make the Embryo

This is not as heard as you might think. If you need extra help then the correct size template for rolling out the modeling clay is available on dadcando, here.

Stretch out a bit of modeling clay to be about 100mm or 4 inches long and make a bulge in the biddle for the body, thin it right down for the neck and then make a large pointy beak. At the other end smooth out the shape into a long pointy tail.

Make two legs and roll a small ball up for an eye.

Then assemble the parts. Put the eye in place on the head and make sure it is securely attached. Then make a horizontal vee shaped slit in it. Attach the two legs (you only need two because the embryo is going to be half buried in the fossil. Attach the legs so that they are blended in at the top of each leg but defined at the sides, as shown in the second picture.

To get that authentic embryo look now bend round the tail and the head into that foetal position. Tuck the tail and the head under the limbs slightly. If the head won't bend round properly, straighten it out and make the neck a tiny bit thinner and longer and try again.

Following the instructions bake the clay (Fimo or Sculpy) until hard.

Actually we made a load (one for each cousin) and these looked really cute coming out of the oven, I'm sure that they could inspire many other projects for things like a computer mouse or a freaky USB memory stick, but that's a different story...

HOWEVER, add a tiny little wing at this stage and you could be making a dragon fossil...mmm

Step 4: Glue Egg and Embryo to Cardboard

position the embryo and the parts of the cap as show and make sure that they all fit together. It doens't matter if the embryo is a bit on the small size, but if it is too big you will have to rework it slightly to make it fit. Don't worry about gaps inside the egg, you are going to be filling those in.

Use the other bits of the cap to be the tip of a second egg, looking like it has only just been exposed but not fully excavated. This way you get two fossil eggs out of one lid.

If you have more than one lid, then cut the others in half and arrange in a circle on a larger bit of card. You could put one in the freezer for a few minutes and then break it with a hammer so that you have lots of pieces which you can then arrange to make it look like there were some broken eggs lying about in the nest too.

Make sure that the two halves of the open egg match up and trim them if necessary.

Once you are happy with the fit and the position, glue the pieces down.

Step 5: Fill With Filler

Using tile grout, plaster or builders' filler fill the inside of the egg using the wrong end of a spoon or artists paint brush or lolly stick.

This is the most fun. I felt like I was making the fossil and revealing it at the same time. I can see what fascinates paleontologists, all the picking away is very... moreish.

Fill the eg only up to a certain height so that the embryo is poking out of the layer of filler. Don't worry too much about getting it all over the embryo, in the next step you are going to pick away at it and brush it off.

Once you have filled the egg, put filler / grout over the card and around the bits of egg to about the same level as the filler inside the egg.

Step 6: Clean Up the Fossil

When the filler is mostly dry, but before it is hard, pick away at it with a cocktail stick or a small screw driver. The oven bake clay is very tough and will not damage, so you can really go to town on the filler. it's great fun and then every so often while you are doing this, brush over the fossil with a scrubbing brush or toothbrush until you have the look you want, with just about the right amount of fossil embryo revealed.

Step 7: Paint and Distress the Fossil

Spray paint your fossil. Some fossils are a bronze colour, and some are grey and others a a reddish colour, I guess it all depends on the earth present at the time the thing was fossilised. the main thing is to get a base coat down of whatever colour you want and then distress the fossil a bit.

Distressing is easy, all you have to do is paint on a darker contrasting colour and wipe it off as you go. The paint goes into all the cracks and when you wipe it off the raised areas look lighter and the fossil immediately starts to look old. The best bet is to use permanent paint for the base coat, ie either spray or household decorating paint (Emulsion (UK), Latext paint (US)) and let that dry, and then use acrylic watered down very slightly for the distressing so that when you wipe it off you don't end up wiping the base coat off.

A nice project download with the templates is available at dadcandodadcando, so do go along there and while you're there you'll see that there's quite a few other projects like this one to do.

have fun and post any pictures of the fossils you make, the world could do with MORE fossils!



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    39 Discussions


    9 years ago on Introduction

    Exscuse the blurry picture, but here is what I made.
    I decided upon a dinosaur baby in a jar...

    1 reply

    9 years ago on Step 7

    This is really cool. My sons will love giving this a go. Thank you so much for posting this and for taking great pictures.


    10 years ago on Introduction

    these are so kool!!!!!!!! i wonder i could make edible ones out of gelatin????


    10 years ago on Introduction

    this is awesome. i made three of them (although one was a variation) and gave them to my sis. she loves them

    5 replies

    when you write a comment look at the top edge of the box, one of the TABS says ADD IMAGES, click on that one and then browse for your images on your computer and that's all there is to it.


    thanks here you go. i decided not to make the eggshell so they're not technically fossils but whatever. if you want more detailed pics just ask.


    Oh I like, very much. If you go to dadcando and look in the dragonry you'll see my aurified dragon embryo... they look very much like those. Looks like you had fun. thanks for posting the images.


    Reply 10 years ago on Introduction

    thx, glad you like it, I've hit on a bit of a sort of embryo and egg making theme this week, I am currently just finishing a dragon, with a really nice filigree egg. I might post that soon.


    Reply 10 years ago on Introduction

    Here's a couple of sneak preview images to get you thinking. The baby dragon is similar to the fossilised dino, but the egg case is completely different and really cool. I am just drawing and writing up the instructable for that now


    yes, looks cool doesn't it, the dragon is a version of the dinosaur embryo sprayed red and gold and then distressed a bit. I'm half way writing the instructable but I have been very busy for the last two weeks.


    cool. To make the baby dragon just make a longer dino body add some vestigial wings and roll up in the same way, bake, spray red, then lightly spray gold, then distress with black acrylic wiped off as you apply it... and bingo... Sorry, were you talking about the fossil? I have that one on the wall and it looks like something out of a museum