My Furnace Project

[rc62burke]

Hi All
I thought I would show you the progression of the "Furnace" build that I am working on ATM.

I am using a 9kg gas cylinder for the vessel, so all there was to do to this point is to, remove the valve, cut off the top ring/ shroud, cut the top section for the lid, cut out 2 holes one in the lid & one in the side down low, then I needed to make up the pivot point & lid support.
That is about as far as it goes for now.
I need to order the refractory cement & make up the mould to pour the internal of the furnace, here are some pics, I will post the next stage when I have the stuff, I will put up the plans for this when I have finished that way I can add any helpful comments to help any one who wants to build one.







cheers
Lee

 

[MJB]

looks the goods Lee

 

[Sa_bogan]

looking good mate, would like to put one together for myself for all the metal were finding on the beach

 

[Oldfella]

Very interested in seeing the completed Item. Great work

 

[GWT]

Gday Lee,

Awesome build. What will you be using for a heat source?

Cheers

Gerard

 

[rc62burke]

Hi Guy's
Thanks.
The heat source this furnace is designed for is a Gas burner!
However I very rarely run true with design parameters, my wife says I am always "re-inventing the wheel".
So in saying that & knowing that Gas will be costly I will try a few different methods, charcoal, wood fired with blower, waste oil with blower? one should not limit ones self should he???????
cheers
Lee

 

[thedigger]

Hi Lee
This youtube video will help you in building your furnace,go to 27 minute mark,has some imfo
http://www.youtube.com/watch?v=WWVVSZP3Au4
In your post you stated " some methods recommend adding a few bits of quartz or glass to the flux to get right fluid mixture"

What they did in the old days was to used glass and borax,the glass was to get the soda ash,which helped clean the gold.If you look around some off the old mines you will come across what looks like melted glass,some will different colours,this the remains of the flux used in the gold melting .
I use a salamanderclay/graphite crucible,will take high temp and will not crumble as graphite will.
In regards to refining,this can be tricky,need a vacum pump to filter the silver,and also all the chemicals need to be analytical grade,along with killing all the nitric acid before you add the sodium bisulfite.
The oven I use is electric and I have to get to 1300c to make sure that I can pour the pure gold
I hope this helps,so any questions feel free.

Regards
The Digger

 

[AtomRat]

Hi mate, I have made several burners now in the past, mostly running on waste oil, we did make an electric one for alloy using a PID controller and a coil element.

You do not need to buy a fancy refractory clay if you dont want to. Something as simple as Perlite and Sodium Silicate can work, or if you can get your hands on some, look out for Kaowool ( made from Kaolin clay ) I recommend doing some small tests on paint tins before making your final decision as you will find that many of them crack.

I use mine for smelting alloy, brass, copper and also some forging for blacksmithing. One day I will make two waste oil blowers to fire into a blast furnace so I can test out smelting some iron as well, I just dont want to burn out my alloy ones to do that as they cannot handle the heat.

The electric one we have goes to 1500C, the waste oil gets to 1300C.

The reason we chose the electric and waste oil was just what you said too, unless you have a constant supply of LPG gas from somewhere, it is just too costly. Using LPG to start the waste oil unit can be done though.

The next one I make, the whole burner and crucible will be joined, and the unit will tip on a hinge with a handle. Im expecting it to smelt and pour 10 kilo of molten alloy.

 

[rc62burke]

Hey Digger
Thanks!!

Hey Atomrat
Thanks for that info.
Do you have any details or advice on the waste oil burner as I have not looked into this yet, I will consume as much info as you can put on the plate mate!!!
cheers
Lee

 

[TenOunce Tone]

Some great work hoing on here guys. Looking forward with intrest to see the end product and results. I may be looking at making a forge in the near future for some wrought iron work or maybe cast iron.. Good luck with it Lee

Cheers Tone

 

[ChrisM]

Hi Guy's
Thanks.
The heat source this furnace is designed for is a Gas burner!
However I very rarely run true with design parameters, my wife says I am always "re-inventing the wheel".
So in saying that & knowing that Gas will be costly I will try a few different methods, charcoal, wood fired with blower, waste oil with blower? one should not limit ones self should he???????
cheers
Lee

Thats a good looking piece of gear your building there Lee
Looking forward to seeing the continual build on this baby.
Just the other day I was looking at an alternative to needing to pay out for oxy/acetylene rental at work. I predominantly use it for bending and heating and not much more.
I came across this product that seems to tick all the boxes including portability and cost. I'm not sure if you can adapt a pressure system like this to your furnace build [if it can reach the required temperatures you need]. All considering that there is a robust backflash unit in-line fitted, it could be something to consider.
http://youtu.be/hjp9kNWgrl4
Cheers
ChrisM

 

[AtomRat]

I use mostly waste oil from fish n chip shops or used oil from vehicles. Usually you will need to have a decent flame going first before you can catch the oil on fire. You can use propane or even a small fire from sticks will be enough.

It seems so far, the best nozzle I have had going is a gravity drip line about 6mm diameter welded into a piece of old exhaust 2" with a fan or hair dryer on the back. What exactly do you want to use the furnace for as there are several different ways to get the unit working right. Some have used pre-burners or oil warmers to heat the oil before it gets to the flame, but it is not necessary.

Keep your eyes open for cheap fire bricks as well though. Kiln and pizza oven makers will sell the bricks for $2 - $5 each.

Waste oil burners are very simple, instead of explaining what I have, I will upload some photo's for you instead within the next couple of days.At the moment we have a waste oil forge for blacksmithing.

If you are only smelting alloy, copper and brass, a steel welded crucible will last for playing around with. If you want a crucible to last, go for the graphite clay crucibles.

Using oil, the flame goes from orange to a white at its hottest burn. If a furnace has been made correctly using refractory cement, wool or clay, the heat will stay within the unit and reach the temperatures you will need. Try to keep the shape 'circle' to always have a spiral flame surrounding what you are burning.

If you have not smelted yet and you want to know the main dangers ( yes there are some important ones you should really know ) of smelting at home, then please ask, and I will explain what can ( and has ) go wrong when pouring or dealing with hot metals.

 

[Goldtarget]

Hey Chris M, I converted to Oxy lpg mix all I wanted was cut and heat proved to be around 40% cheaper after I configured the gear. Used a 90 pound bottle filled at the servo (note this requires a little more background checking is not quite that simple) and changed lines for under $400. Over the course of year I worked out I saved nearly 5K from doing this. Not an option for everyone but very doable.
From memory the lines and flashbacks cost $160, lpg guage $65, lpg bottle with servo nozzle custom fit $150 including stamp and certification. I've thought about selling the setup a few times but never actually done it I always find a reason to keep it. Put it up against Oxy acetylene same configuration, cuts are broader and far less straight and heat output and times are a little slower but huge difference in gas costs not to mention the rental.