A first project to break in a new furnace

Before you laugh at the Halloween themed furnace, I could not help it, the container was the perfect size and had for free. I thought the paint would burn off after the the third time the furnace has been fired, but it seems my refractory is that good, despite the sloppy novice looking concrete work


So recently, I built the furnace I was talking about that would be much better than the one in a previous post, and here it is, In the above picture. Unfortunately, I didn't get any pics of the building process. This new toy of mine has a lining of 3000 deg F rated castable refractory, 7 3/4 diameter burn chamber, and is souped up with a Ron Reil propane burner. The first firing consisted of charcoal and a bit of forced air to burn out the center form- a core on which paper would be wound onto at the mill. The second firing was a test of the propane burner I built during which I melted a couple handfuls of brass keys. It was a roaring success.

This post details the third firing, for a more meaningful project. I have a good friend who has been battling throat cancer for a while now, so I decided to make him a little something because he is interested in what I do when I melt metal.

Last night, I carved the pattern for the piece to be cast from lost foam. I have not yet built a hot wire foam cutter, so a big bread knife was used to cut the shape. After that, a small screwdriver heated with my propane torch made an engraving tool, followed by sanding with some emery cloth. As you can see in this pic, I covered part of it in drywall compound. Why not the whole thing? Because this project is also a learning experiment for me.

The next day, the drywall compound was reasonably dry, so I fired up the furnace loaded with aluminum drink can ingots I made in the past.

Once the metal melted, I skimmed off the dross. There wasn't a lot of it either. The pour went well. Here is the raw casting:

And cleaned up a little:

It is just a little decoration with my friend's initials and a cancer ribbon. Despite the casting coming out perfectly as it should, My head slumped in disappointment, And I learned I have a great deal to learn about workmanship. This is my third lost foam casting, but the first on something I want to do, rather than screwing around, and It is back to the drawing board.

First (Controlled) Aluminum melt

This hole saw tool is bullocks

After spending at least a year reading web pages and watching videos on the internet to learn how to properly build a foundry, I had finally decided to stop screwing around and finally just melt something. I had been studying and overthinking every little aspect of home foundry work up to this point. I was so determined to do everything perfect from the start, that a year had passed before I actually melted some scrap. Needless to say, my mind had become so overwhelmed with information, that the planned perfection was thrown straight out the window by this time. 

Here is my first setup:

Lets start with the furnace cobbled together vessel that generates heat. For this, I used an empty freon can. My father is a HVAC serviceman, and happens to have an endless supply of these in his junk pile. Since it was free, it was a donor specimen by default. I began to turn this into a furnace the same way any other would, puncture it and cut it open. This was all the farther I had gotten a year ago. 

Skip ahead to November, 2015 when I performed the first melt. After a long 12 hour shift at the paper mill, I came home on a Sunday morning, and got straight to work. 

Here are my modifications to turn a Freon tank into a furnace:

1. The lid was re attached with a hinge, and a 3 inch hole was made in the center

2. A hole was made to accommodate a 2" pipe nipple about 2 inches from the bottom. Said pipe nipple was held in place with sheet metal clippings and hose clamps
3. Three holes were drilled around the perimeter and bolts were fastened into them with washers and nuts to accommodate the shelf my crucible sits on. this was made out of a drip tray from a stove. all I did was cut some excess metal off the diameter of the drip tray. Three flat spots were hammered into the tray that corresponded with the location of the bolts I also drilled holes all over it to allow air to the charcoal briquettes that fueled it.

As a crucible, I cut the top off of a 1lb Coleman propane bottle. Before cutting, I removed the relief valve with two small screwdrivers. Its the same principle as a valve inside the stem on a tire, just larger. You could also find a circular metal bar of a diameter that fits the hole where the valve resides and grind a slit in it, but that is a lot of screwing around. I would advise against doing this anyway, as this crucible was only good for one melt.

Here is a shot with the furnace, if you want to call it that, fired up, and I am pushing pop cans into the crucible. To start, I packed some Kingsford charcoal briquettes around the crucible and lit them as you would a grill. Once they were burning, I connected the vacuum cleaner, set to blow air, up to the pipe nipple on the bottom with a rubber coupling. I had a roaring inferno going in it and the outside of the freon can was glowing red at one point. I found that I had too much air going in. To combat this problem, I disconnected it and set it about 3 or 4 inches from the pipe, as you can see in the picture, and this worked much better. 

 Once the crucible was glowing red, I started putting pop cans in, and once I started to get a pool of aluminum, I began pushing them under the surface of the pool with a steel rod. Safety sissies will tell you that you can't melt pop cans with moisture in them. Safety sissies tell that if you do, boiling hot water or aluminum or what ever other liquid name they can pull out of their ass will splatter all over your hands and face and eyes. It's all bullocks. And I defiantly didn't lose my eye sight, as I can clearly see to type this post. I can already hear some one whining, "But wait, you set them in the pool open end up so the liquid could boil out before being submerged! :'0" Well, no, I took the liberty of plunging some straight to the bottom of the melt open end first, and still, not blind of burned. All that happened was the aluminum bubbled a little in the crucible. No metal left the crucible, no violent explosions, none of that. Just a fart in the bath tub. It just goes to show, that when you work with things like this, all you have to do is use common sense, and of course, you can not be scared when your doing things like this. If you are, I suggest you take up, Popsicle stick art, ant farming, video games, or some other dangerless hobby that you can find on Pinterest, and leave this kind of thing to better qualified people. (To hear more rants about this kind of thing, check out this guy. If you are interested in home metal casting, his videos could be of some use to you.)

After I had melted the bag of cans, I poured the metal into this mini muffin tin. Once cooled and time to remove the ingots from the tin, I found myself scratching my head, and saying "Shit." when they wouldn't  fall out. Turns out the cheap ass muffin tin I bought from Family Dollar was Coated in tin or something, and it caused the ingots to solder themselves to it. I had to mutilate the hell out of the pan to free them, ultimately giving up and remelting them at a later date and fishing out the parts of the steel once the alum had melted. 

 Here is a shot of the crucible I built for my second melt. I did not have a choice, as I found a weak spot in my first one when wrapping on it with the corner of a chisel. This one is a 5 inch chunk of 4" diameter steel pipe with a piece of plate steel welded on, and it works great. Especially for melting metal that creates excessive dross, as you can really bang it on the concrete and not have to worry about breaking it.

 So there you have it, Simple and easy aluminum melting. This crude method is good if you are as indecisive as to how you want to build a furnace as I am. This pile was contracted up in about an hour one morning when I got sick of doing research and just wanting to melt some damn metal. Goes to show you can too.