Non-Chemical Building a gold melting furnace.

[Nervin]

I have decided to build a propane furnace for melting gold as well as other PMs and wanted to share the each step as I go.

Ok, I took the easy step first and built my burner tonight. After looking through all the designs, I chose an easy one to start. I don't have the ability to weld yet so I went with one that I just need to drill one big hole and one small hole.. http://forums.swordforum.com/showthread.php?t=68488

Now this is my first time putting an image so lets see if it works.

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6 by Naymond, on Flickr

Finished burner with out the regulator.

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3 by Naymond, on Flickr

Hand Drilling #57 hole

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7 by Naymond, on Flickr

Hole for 1/8th inch pipe

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9 by Naymond, on Flickr

Holds the gas line just nice.

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12 by Naymond, on Flickr

All together..

Now I can put a choke on the back without having to do anything more than drill a hole for the screw. I just found one of my dogs old tags and it is big enough to fit over the 1 inch hole so that will save from having to cut it out. I think the only thing that is a pain in the butt is centering the hole from teh gas pipe. It started to get to be a pain in the rear trying to eyeball it down the dark pipe so I pulled out a bristle from my broom (I know not perfectly straigt but it's better than when I tried to eye ball it) and taped the small drill bit to it and put it inside the hole. Once the bristle was centered (taking into account it was offset a little from being taped onto the drillbit) then I tightened down the flare. Hopefully tomorrow I will have a chnce ti fire this thing up and see if it is going to be an epic fail. Also my shell will be here soon too.. When I decided on this design I not only concidered that it was easy to make but also it has the potential to have forced air added to the back-end of the flare, and even possibly O2? Either way I am hoping the get this thing hot enough to melt Platinum. Any advice is always welcome..

 

[rbramsey]

Either way I am hoping the get this thing hot enough to melt Platinum.

You will not be able to get enough heat to melt platinum. The burner you propose will be good enough to melt aluminum, copper, and brass. It will be enough to work iron like what a blacksmith would need, but will not get hot enough to melt iron. I would think you can expect something in the range of 1500-2000 F for this type of design. To increase the temperature you will need to add forced air or oxygen.

I am looking to build a similar furnace to do some aluminum casting.

Richard

 

[lazersteve]

I put my nozzle in the wide part of the bell, not in the threaded pipe using the same burner design:

Burner Design

Steve

 

[Nervin]

Like I said this is my first furnace and I picked this design so that I can add forced air or O2 without too much modification. Doesn't hurt to try I guess. Unfortunately weather and the little one (teething is fun) prevented me from getting out and buying a regulator for it, so no test burn today. I am also going to add a pressur gauge at the tank, and a safety shut off valve at the burner.

I have been researching some bore designs and although the standard straight design is normal and works just fine, I found one called the flam trainer that I am going to try out. It looks like it focuses as much of the heat onto the crucible as possible. I can forsee efficient heating but hopefully some nice temps too.

Lazer, I definitely like that design, wished I had seen it before I started. If this one fails then I will definitely check into trying that one out.

Can anyone tell me what a good crucible would be. Silicon Carbide? or Clay Graphite. I have to get pick out and order my crucible before I calculate the bore size of my furnace. Any advice? I know there are pluses and minuses to each, but I am just wondering what is the most common one used for PMs...

 

[Barren Realms 007]

Look at Steve's web site he has some that do a good job.

 

[Harold_V]

It looks like it focuses as much of the heat onto the crucible as possible.

Flame should NOT impinge directly on the crucible. It should be directed around the crucible, where it heats the opposing walls, which, in turn,reflect heat back to the crucible. That way you avoid superheating the specific portions of the crucible.

Harold