…was required for the refurbishment of Big Heritage‘s Chester visitor attraction.
The general idea was some kind of mad scientist laboratory prop with flasks and coloured bubbling liquids.
Not being a thing we had done before some research was undertaken first to find out where the science stuff could be bought from. I ended up with a mix of Ebay for the glassware and a trade supplier, Rapid Online, for the laboratory hardware.
After a lengthy wait, due to the pandemic lockdown, in the hope the glassware would arrive intact it eventually did. The hardware was pretty much overnight in comparison and arrive first. A quick assembly in the workshop was needed to make sure it would all work out and in the end a third clamp was needed.
After the glassware arrived it was all set up to see how it would go together. A fish tank air pump would be used to blow bubbles through a clear silicone pipe.
To hide the air pump a plinth was made. It was made from four sides of softwood, painted satin black, and an oak top made from pre-finished oak floorboard off cuts. The oak boards have bevelled edge and the look is in keeping with other pieces made.
To fix the laboratory stand to the plinth without ‘visible fixings’ I decided to weld some nuts to the underside of the stand base. The heat damaged the blue paint so it was a good time to respray it in silver so it looked more like the stands I remember from school.
Underneath the plinth I hid the fish tank air pump. A hole was drilled through the plinth, and the stand base so that he air pipe would run up behind the upright of the laboratory stand.
The power cord from the air pump was fed out of the back of the plinth and an inline on/off switch was added.
The prop was tested using green and red food colouring. The air pipe goes into the top flask through a bung and into the green water where it bubbles. The air is trapped by the bung and is pushed through the condenser coil where it enters the bottom flask. There is a pipe on the end of the condenser that blows bubbles in the red water. This had to be done in the kitchen so spills of food colouring wouldn’t stain other projects in the workshop.
The prop needed ‘more’ though and as the condenser didn’t have coolant water running through it it looked unfinished. So some parts were designed and 3D printed.
The printed part is intended to give the impression of an electrical bolt terminal attached to the condenser. Some cloth wrapped flex, that would have been used for older electrical appliances like toasters and irons, was found in our stocks and used to provide power to a blue flickering LED inside the printed terminal bolt.
The 3D prints were then painted with gold and silver paint. They would be ‘weathered’ and ‘aged’ later to stop them looking so new.
Two more of the printed terminals were used in the oak plinth as a way to terminate the LED supply wiring.
This gives the impression that there is some sort of high voltage, high power electrical supply going to the condenser.
There is an LED driver built into the plinth, adapted from a phone charger, to provide power to the LEDs. It is switched on with the air pump by the same in line switch.
So with the LED wiring completed the condenser looks like this. The printed terminals were fixed in place with hot glue.
And with the blue LEDs powered the glass in the condenser glows a little giving a sort of neon arc effect.
The whole assembly looks like this. Once we were completely happy with the set up the plastic handled bolts were swapped for M8x40 bolts and the clamp for the condenser was thread locked to prevent tampering.
Only the two clamps for the flasks are operable now so the client can remove the flasks for cleaning and refilling when needed.
There were some interesting effects as the green water bubbled through the condenser.
And when we tried reversing the direction of air flow, from the red flask to the green flask, this happened! A very interesting effect but resulted in a very rapid transfer of liquid from one flask to the other.
Prior to delivery we decided to reduce the liquid volume to prevent transfer and returned to having the flow from top to bottom as it meant easier access for refilling.
We also decided to only use a single colour as it reduces the chance of the colours mixing as bubbles pass through the condenser. Our test run resulted in the water just looking brown after a while.
We think it looks lovely now it is on site.
A last minute addition was our makers mark. 3D printed in relief using a bronze coloured filament, satin black spray, and then the surface sanded back. It was recessed flush into a 2″ hole drilled in the plinth.
The Client is very happy with the prop. Topping up the flasks is easy, and it makes a soothing bubbling sound.