Sunday, May 10, 2015

Smelting - from offcuts to metal ingots

©2015 Fiona Dempster - Silver-plated copper begins to melt at 1085C
On Friday I did my first metal melt with my small electric furnace. In Friday's post I shared some of the outcomes of that experience - not perfect but a good first effort and a lot of lessons learnt.

The whole process really started because I wanted to use the small and odd shaped silver plated offcuts (silver over copper and silver over brass or EPNS). Since I purchased the furnace a couple of weeks ago I have been cutting some offcuts into small fragments that would melt more quickly in the furnace. I have kept the pieces in separate buckets - silver over copper; and silver over brass.

©2015 Fiona Dempster - Small pieces of silver-plated copper
The furnace is quite compact - the biggest crucible I have is supposed to hold 3kg of molten gold when full. The crucibles are solid graphite - which I had cured during the week - takes a couple of hours.

©2015 Fiona Dempster - Small electric metal melting furnace
©2015 Fiona Dempster - Cured graphite crucible full of silver-plate offcuts
My first smelt was with the silver over copper. These were place in the crucible; and were topped up when the metal started to melt at about 1100C. Pouring was a new experience - white hot crucible held with tongs and leather glove. But lovely to see the metal running into the graphite moulds which had been heated but not fully cured.

©2015 Fiona Dempster - White hot crucible - metal and borax flux fumes being given off - all the more reason to do this outside on a solid tiled and well ventilated work area
©2015 Fiona Dempster - Molten metal 
As you can see from the heart shot - the mould was basically on fire with the heat of the metal - it did not burn second time around as it had cured.

©2015 Fiona Dempster - Heart on fire - graphite mould curing itself!!!
The hot metal needed to be quenched in water - still very very hot even after setting.

©2015 Fiona Dempster - The silver-brass heart quenched
And the outcomes look pretty grubby initially; but as you know from Friday's post they polish up well.

©2015 Fiona Dempster - Front of the silver-copper heart in the rough on rust
©2015 Fiona Dempster - Back of the silver-brass heart on wood after quenching
Some of the lessons learnt include: good to have two pairs of hands; good to direct gas flame onto the mould and the pouring metal so it stays nice and liquid; good to have a full face mask to deflect the heat; and good to have moulds with wide apertures when one is a rank novice. Still I'm sure the second round in a few weeks time will be interesting.

Thanks to Fiona for the photos (and there are many more) - but next time I think she will be the second pair of hands.

The metal is an amalgam of silver-copper and silver-brass - both have there own rich beauty.


  1. the process is fascinating and i thank you for sharing it... what i love is how the metals separate with the temps - the beautifully reticulated silver sitting atop its base... body and soul... individual and yet joined... they hold hands so wonderfully.

  2. I've always wanted to do this but I think I can now be satisfied to know that you're doing it Barry. What a wonderful process to see through Fiona's photos!

  3. Hi MJ and C - thanks for your support and encouragement - I loved doing this - and am excited about the serendipitous nature of the whole process - separate but joined - I like that. C - maybe one day when you visit can have a play with metal. Go well. B

  4. so interesting to see how serious working with hot metal is...and looking at your photos i kept thinking i might see the hands of another underground-dwelling person come to visit and help you out. once on a camping trip with hooligans and adults (all male) one guy carved a little wooden mold and heated up some found metal, poured it in, and made a little beadlike thing. i was fascinated. on that same trip one of the fire-pit rocks split in half with a big sound. we all returned safely.

  5. ooo ... it's interesting how the surface of the heart turned out. Like reticulated metal. Super cool (or hot) and so very fascinating!


Comments are welcomed - it is good to connect with fellow travellers.