making london zoo's goat arch

		Last year, I made an elaborate clock for London Zoo, and I had been hoping it might lead to more work. So I was delighted when they rang to ask I would like to make an entrance for the zoo’s children’s area. The brief was some graphics, the visual look for the area, and a list of the animals they hoped it would contain. I was tempted by some of the exotic animals but goats were the obvious choice. My 5 year old grandson shows no interest in zoo animals except goats. They are usually the one animal you can still touch and feed. Also goats have attitude. My local zoo (Africa Alive, in Suffolk) has a 50p coin operated food dispenser, like the old nut vending machines in pubs. You turn a handle and the food falls out into your hand. The goats have this machine completely sussed. With precision timing, they barge you out of the way and get the nuts straight from the machine into their mouths. If this fails, there’s another goat that jumps onto a brick plinth nearby so its at your eye level. It then begs by putting its head on the side and looking ridiculously cute.

I was considering different ways to get the sign to move when I thought of hanging the letters from a rope. It then didn’t take long to get to a goat tug of war. At first I assumed the goats would need jointed legs and necks to look as if they were pulling. At the same time I was also considering standing them on a pile of car wheels because the zoo were keen to use recycled materials. The closest I got to a ‘Eureka’ moment with this project was when I realised that if each goat stood on a vertical car wheel which rotated a small amount, it gave a good impression of goats pulling without any complicated leg or neck joints. The budget was very tight, but this simplification made the idea seem practical.		Goat pulls rope with hinged legs and neck whole goat rotates on wheel below

		The proposal then went to a board meeting. I was nervous about this. I always prefer to take on projects that are below the radar, but I knew this would get full scrutiny. I was right to be nervous. The feedback I got from the meeting was that the directors wanted everything to be made of natural materials, and wanted frogs pulling a worm instead of goats having a tug of war. In the past, I have sometimes just accepted changes like this, but the final objects never turned out well. The only alternative is to act like a prima donna artist which I hate doing, but reluctantly I asked to meet the directors to discuss the design. It took over a month to find a date, but this turned out to be to my advantage. By then it was too late to start from scratch and even better, they had forgotten most of what they had discussed in the original meeting. My idea of making the columns out of car wheels didn’t survive. Having suggested they could be rusty, in a futile gesture to make them ‘natural’, the columns then couldn’t provide the structure, because their strength couldn’t be guaranteed. The ramifications of an internal structure with rusty car wheel cladding would have broken the budget, and started to seem pointless anyway. Recycling and reuse often seem incompatible with our health and safety culture.

		In retrospect, I guess the technique of presenting designs as simple cartoons, so they are quick to grasp, has its drawbacks. Cartoons don’t show the numerous unglamorous doodles and calculations I go through to decide whether an idea is practical. The final cartoon takes less than an hour, even though the thinking behind it has gone on for weeks. In a cartoon drawing, its easy to swap a frog for a goat. It’s not obvious why its not so simple with the final object.

Technically, the main problem was to stretch the rope enough when only one goat pulled to be satisfying, but not to overstretch it when both goats pulled at the same time. It was surprisingly difficult to get a feel of the different factors involved – the geometry of the pivot points, the weight of the rope and letters, and the optimum positions for springs, rubber cushions and counterweights. It looked brilliant when the rope got really taught so the letters crashed down violently, banging into each other with a great clatter, but I feared the whole contraption couldn’t last long working with such force. Gradually I fixed one element after another, each time making it simpler to see how the remaining ones interacted. Although the process was a bit haphazard, it wouldn’t have been possible to do with CAD. Trial and error still has its place!


		The other part of the job was making the goats. They will be the focus of attention, and in a zoo, it seemed particularly important to get them right. Last summer, I had made a robot walking dog for a friend. I made this out of 1.2mm soft aluminium, which I’d never used before. It was great because unlike copper, it didn’t constantly need re-heating to keep it soft. I could just keep hitting the metal until it was the shape I wanted. The dog looked like an oversize tin toy, and I liked it, so I thought it would also be a good technique for the goats.


However, while making the dog, I really didn’t know what I was doing, so I decided to find out more about panel beating. I bought two great DVDs by Ron Covell. Each one was 90 minutes of him hammering aluminium. It mostly looked obvious when I was watching, I only appreciated the subtlety once I’d started hammering myself. My other research was a trip to Frost’s, an old established metalworking company that has survived by selling tools to rich people restoring old cars. They kindly arranged for me and my friend Andy to try air planishing hammers, wheeling machines and shrinkers. Neither of us liked the planishing hammer – violent, noisy and not very effective. Their own expensive wheeling machine was a joy to use, making perfectly smooth gentle curves, but not tight enough for my goats. The shrinker crimped the edges of a sheet inward. This looked useful so I bought one, but I’ve never actually used it. Instead, I’ve just got a bit better at hammering the aluminium.		The parts were quick to make, but often came out wrong


		It still seems amazing to me that using only a hammer its possible to ‘shrink’ metal as well as stretching it. The trick is to bend ‘crinkles’ in the metal and then virtually hammer them down, squashing the metal on to itself. The description never made sense to me until I’d started trying it, and even then it took a while before I made it happen. Each section of goat was a new challenge. The scale is smaller than a car panel but bigger than silversmithing so I had to mix techniques from both crafts, with quite a lot of bodging as well. I found the temporary rivets used in the aircraft industry brilliant for setting up panels before finally riveting them, and I don’t think I could have done it without an air powered pop riveter – amazingly quick, accurate, and trouble free.


After the parts had returned from being powder coated (painted), Graham had the brilliant idea of assembling the whole thing in the yard by guying the columns. After a few days it stopped working. This not only revealed a serious design flew, but also that the mechanisms were far too slow to remove. I now can’t imagine how I ever convinced myself it could be OK to take it to the zoo without a full test. After this invaluable test, the installation was very quick and efficient, thanks particularly to the friendly contractors (Comcoy), who quickly found us everything we needed!

Several months later......

Soon after installation there were some really strong winds and the letters blew over the top of the rope making the sign almost illegible. I couldn't think of an easy fix so I was despairing. However, the zoo didn't ring me to complain, so I left it to see what happened. When I next visited, the letters were fine, completely untangled. I think someone had flipped them back with a long stick. Its a very good omen that they are happy to do things like that!

I've been back several times now and although its not that spectacular, it does seem to engage kids exactly as the zoo interpretation team were hoping. I'm delighted how enthusiastic they get - I've seen several kids desperately trying to turn the handle while simultaneously peering round the back to see the chain mechanism working. If I had anticipated this, I could have spent a bit more time putting the glass door on the kids' side. The idea of having it work automatically when no one has touched the wheels for a while is also a great success at attracting attention, particularly from a distance.