Part of the welding module was a design-make project, the brief was to work in pairs to design and fabricate an animal from the scrap metal in the bins in the welding area & forge, the downside being – we only had two lessons to do it in! I was teamed up with my pal Ali, she’s the same age as me & we’re both very passionate about our work so it was a great fit.
We were told that cutting must be minimal as there is only 1 plasma cutter and 1 acetylene torch so not enough for everyone at the same time, which meant we had to be able to construct our creature mainly with the forms that are in the bin.
I took some of the photos below for inspiration, hmmm, what can you make with that?
Most of the scrap pieces are rectangular bright drawn or hot rolled steel section which has been welded (badly) into T sections with fillet welds, or butt or lap joins. Looking at the scrap in the bins we deduced we will need to make some kind of plated or armoured creature.
My thought was armadillo, woodlouse, or dinosaur?
In a moment of clarity I remembered a weird prehistoric creature from one of the BBC’s walking with dinosaurs series that my son was obsessed with. If Only I could remember what it was called! I knew it looked like a massive woodlouse and was around over 400 million years ago, it was something like trigladite or troglodyte, so I searched the internet. Turns out a troglodyte was a prehistoric cave dweller and a trigladite doesn’t exist. I’m sure I’m not making this up, think harder!!
I searched ‘massive prehistoric woodlouse’, that brought up some strange creatures! And in with them was a trilobite! We searched the internet for images of trilobites to aid our artistic vision.
A trilobite is a prehistoric creature that lived 400million years ago, there are over 20,000 known species, with more being found all the time which makes the trilobite one of the most diversely evolved species earth has ever known. Some trilobites are just 1mm in length, others have been found at over 700mm! (That’s your lesson for today folks!)
Our first stop when we got into college on build day was to check the scrap in the forge & I’m glad we did!
There were lengths, shapes and even ‘antenae’ in the scrap. We pulled a few long bits that could be our trilobites tendrils, then as luck would have it I spied two curled flat irons & thought they would be perfect for our trilobites front tendrils. We checked with Ricky (head blacksmith) before making off with them, they looked so good!
We spent quite a while moving pieces around & working out what should go where while we kept looking at the images we had brought & adjusting the shape to suit.
Laying the pieces out all we were certain of is that we wanted the curled antennae coming from his head & another curved bit with a straight flat already welded to it was going to be the front of his head.
We got to a stage where we were happy with the shape our creature was taking & had a plan, but we decided we were probably best off building a frame to support all the flat plates of ‘armour’ before trying to go too far as it kept falling apart. As we were outside we could only use the stick (ARC) welder as the gas wouldn’t be able to shield the weld if we used TIG or MIG, plus there was a small mobile stick welding machine which made life easier. All we had to do was shield the area so no one could see the flash of the welding. We wanted to plump out his back to make it 3D rather than flat, so we needed to create a mound shaped framework for his back to attach the armour to later. We tried using a triangular piece of angle iron and a length of flat steel in various arrangements.
We took our scrap welded angles and placed them on our frame to work out how they sit best to create the most realistic shape for our trilobite. They kept falling off obviously so we found we couldn’t go too far with the design at any one stage. The design was evolving on it’s own, as it so often does when fabricating with scrap.
We came up with an idea to put the welds on the inside of the plates by turning the trilobite upside down and working on the inside of the bottom plates first. This meant you wouldn’t be able to see any build up of slag that was present & we wouldn’t have to worry too much about chipping it off. (The downside of stick welding is the residue it leaves behind which is called ‘slag’.)
Next the plan was to fill his flanks with more steel sheet. I think in hindsight it might have been better to use smaller sheets for his sides?
Above – He looks quite boxy & square at the moment, we needed to think up a way of making him softer on the edges & more organic.
After a good nights sleep I had the idea of putting some of the sheet metal we had through the swaging machine which we’d asked about a few weeks earlier. I also wanted to use the acetylene torch to heat the edges of our creature and hammer them into a downward curve, we’d have to ask our lecturer if we are allowed to use these processes next week.
(Above) A swage machine is used to create a decorative ridge in metal, this was used a lot on 1950’s cars as it also ads strength to the material.
You can fit different wheels to it for different effects & the wheels can also be moved closer or further apart depending on the thickness of the metal and the depth of the groove needed.
We welded more scrap welded angles onto his back to create the ridges the trilobites have in our design pictures. Because he tapers in towards his rear there wasn’t really enough room to put a middle ridge on him at the back & it look right, so we had the idea of giving him a fin which was a triangular piece of scrap we had contemplated for his head previously. Time was now seriously running out, we hadn’t fixed or even cut the galvanised sheet yet, and we still had his face to do!
I found a tape measure and did some measuring up for a guide to cut our galvanised sheet to. We got a chalk pen and Ali drew out the lines to cut to. We were going to use tin snips to cut the sheet because we didn’t want to heat the sheet unnecessarily as it could be dangerous. Cutting the sheet this way took quite a while! Mainly because we had reinforced it’s strength by putting ridges in it with the swage machine! You live and learn!
If I used this technique again I’d spend more time finding the correct materials and cutting them to size before swaging them. With our lengths of swaged sheet cut down we had to weld them in place, this was not going to be a nice experience, (because it is galvanised) but very necessary!
Above – You can see the galvanised sheet with the swage machine decorative ridge down his sides. We wanted to add a more streamlined shape to him and detail & texture so I used the Procreate app on iPad pro to draw over our photo to see what we wanted to do & get an idea of how it would work.
And that’s how we built our trilobite sculpture!