Bronze Casting 3. Equipment.

by John

I have been unwell for 1-2 weeks with a respiratory disease.  I twice requested Covid-19 testing, but was declined because I fell outside the guidelines.  At the same time my wife fell ill with similar symptoms, but her situation rapidly worsened with severe asthma, and she required a hospital admission.  She was given the Covid test, but it was negative, and it turned out that she has a different virus named RSV (respiratory syncytial virus) which causes croup in infants.  So it seems likely that I have the same virus.

The  problem is that we are coughing constantly, and sleep is very interrupted.  And we need to continue self isolation just to avoid coughing near other people.  I feel some empathy for infants with croup.

So not much happening in the workshop.

But I have been accumulating various bits and pieces  that will be used for bronze casting pieces for the Armstrong cannon project.

First, the metal melting furnace.  10amps, 240v, 2600w, 1200ºc.  Graphite crucible.


This should melt alu, copper, bronze, but not steel.  Is there a town named “Italy” in China?AUD$405


And some quite reasonable gloves.


A second furnace is needed to prepare the mould.  This was a quite old pottery furnace, used by a lady for ceramic painting.  Purchased by me second hand, (AUD$700) and knowing that some repair work would be required.


It is a good size, and heating coils are intact and well seated.  I do not know if the thermocouple works so I have ordered a spare.


The firebricks are in excellent, almost unused, condition.


It is using the rated 2600w.


The electrics work, but most of the joins and fittings are rusty.  I will clean up the joins, and replace the fasteners.  I also intend to replace the power switch with a digital control.


To make the mould I have chosen (on advice) a jewellers investment powder, normally used to mould rings and brooches with very fine detail.  It is not cheap (AUD$130), and must be handled carefully and not inhaled.


The steel mould cylinder, and rubber end piece.


Wax cylinders to be used as supports, sprues and vents.


And finally, the vacuum unit, for removing air bubbles from the investment powder mix, (AUD$200)

A significant financial investment, and not finished yet.  And no guarantee of acceptable results.   I did obtain a quote from a professional caster, but it was even more expensive.  So, I will be giving bronze casting a trial soon.