Cretaceous Concrete

Life will find a way!

I have fact checked it...Triceratops did indeed roam during the Cretaceous period.

Now that that's out of the way, The Cretaceous Concrete project creates a garden folly, in the form of a Triceratops skull.

A talking point for children and grown ups alike, all banding together to say "where the heck did you get that?"

And the answer is...

It wasn't got...

It wasn't found...

It was made...

...and here's how!

Materials

Chicken Wire

Canned Spray Foam x 5

Cardboard

Spray Mount Adhesive

Thin Set Concrete - I used Evostik rapid set external grade tile adhesive - 20kg

Clear Waterproof Sealent - I used "Thompsons WeatherSeal"

Tools

Hot Glue Gun

Pliers / Snips

Craft Knife / Scissors

Sandpaper - Generally Rough ~80 Grit

Optional File / Rasp

Tupperware / Similar Mixing Receptical

Whisk

In order to make the template, there were a few things i needed to figure out.

1) Why am I doing this? - don't know, don't care, & having fun with my kids - a glorious reason!

2) What size will it be? - as I'd planned to make it in concrete, it was important that the skull would not be too heavy, or too unwieldy. I made this in my small workshop (glorified garden shed), so I knew i had to be able to carry it out the door. I also wanted it to be sizable - something akin to full scale. In the great balancing act, I decided that it would be around A1 in size (841x594) - that is to say, that the template would fit on an A1 sheet.

To make the template, you will need two large print-outs. I simply, googled "triceratops skull" and printed one of the first side view skull images that I found.

Note: you will need two print outs, as there are two main faces to the template - a left hand side, and a right hand side, to do this, I mirrored the print in adobe acrobat. There are numerous ways of doing this (and google is your friend)

See Photo 1:

After an embarrassing attempt to draw the skull (no you will not be seeing that!) - I knew that the best bet was to print out a drawing.

I simply, googled "triceratops skull" and printed one of the first side view skull images that I found.

I printed at A1, as such it is terribly pixelated, but that doesn't matter, remember this is just a rough guide to keep your skull looking like a triceratops and not a giraffe.

See Photo 2&3:

After printing, the left and right template get cut out & mounted to cardboard.

I use spray-mount spray glue to mount the print, and I use simple brown corrugated cardboard (free from the local supermarket).

1. See Image 1 - I used a Hot glue gun to glue the tip of the triceratops beak! After that I forced its frills together in a curve. I spaced the 2 sides of the template away using scraps of wood and carboard, to rough out a three dimensional form. At this point, all I wanted was a rough guide, remember this is all going to be covered up.
2. After the cardboard is formed into the rough shape, I wrapped chicken wire around the entire assembly, cutting myself numerous times before realising I should have worn gloves. I found an old scissors to be the best method of quickly cutting chicken wire. There were no heroics at this stage, the chicken wire is applied in a messy patchwork!
3. I added some spray-foam into the Triceratops snout, just to roughly hold the three dimensional form. Plenty more spray foam in the next step!

Spray Foam - It is so unbelievably messy. See the first few photos, It is sticky. It is sloppy. It has a life of its own, like a symbiotic organism. (At one point I felt like Eddie Brock!) .

The steps are as follows:

1. Gingerly apply spray foam, trying to fill the holes in the chicken wire - and attempt to roughly cover everything - erring on the side of applying too much, as this is easy to cut off.
2. Cut off high points. At this stage I used a hack saw blade, for all of the foam sculpting.
3. Repeat step 1.
4. Repeat step 2.
5. I repeated until I had used around 5 cans of foam, sculpting after each one had set, using the hacksaw blade.

Again, this doesn't have to be perfect, the main issue is high-points. Troughs can always be filled on the next step!.

This is the fun part, as such it's a good point to have an intrepid helper. I was ably assisted by my seven year old son.

MIXING THE THINSET

We used an old lunch box, and mums good whisk, placed in a drill. We added water by eye, to get a smooth consistency, not too gloopy, and not too sloppy, just thick enough to stay in place. The concrete that is used is basically tile adhesive - so it works well in thin layers.

ADDITIONAL REINFORCEMENT

I added a plaster-scrim-tape (for tape & jointing) at the triceratops frill - to ensure no cracks in this important area.

LATHERING IT ON

We used a spatula / filling knife to lather the concrete all over the skull, starting in one quick layer.

LATHERING IT ON AGAIN.... AND AGAIN

Over the course of a week, we did three layers, in between layers, I would knock off any "high-points" - the layers became increasingly delicate and sculptural, as the skull started to reveal itself.

At a certain point, It was time to stop layering concrete, as the poor Triceratops skull had started to become fat.

LOCAL REPAIRS

There were a few points where it was clear that the concrete cover was thin, these areas got local touch ups (see photo 1).

SANDING & CARVING

The final touches were achieved with rough 80grit sandpaper and a scraper / filling knife. This was essentially to smooth out the skull, with some local details added to retain some weathered character. (eg. the joints)

As this Triceratops was going to live in the garden, i decided to apply some clear concrete sealer. I used 2 coats of "Thompsons Weather Seal" . It looked terrible when applied, but thankfully dries completely clear, creating a waterproof(ish) surface, that causes water to bead, and not soak in. In Ireland, it seems to be raining more often that it is not raining. - I needed to give this Triceratops a fighting chance of surviving the elements.

After a precarious journey from the shed, the triceratops skull was placed in the garden and christened Terrence.

No-one knows about Terrence's secrete card-board core... so shhh..!