Flowerpot furnace for melting aluminium.

The following pictures show a flowerpot furnace I made from instructions I found on the internet:

http://www.backyardmetalcasting.com/

The instructions are gone now and have been replaced by a booklet that can be bought. I was fortunate enough to see the site before that happened.

This furnace has melted aluminium quite easily and didn't take too long to do it, either.

The basic part for the furnace. A 3.5 gallon drum and a big flowerpot. Note the black ring on the drum, that's where the blower hole will go. It goes on right through the lower edge of the flowerpot.

Ordinary cement (no sand) was mixed with water until quite slushy then put in the drum. The hole in the side was sealed with Duck tape. The hole in the bottom of the flowerpot was bunged to stop the cement squidging up through it. The pot was pressed in and the whole thing weighted down, otherwise the pot rises up. Let it go off a little and then dig out the hole in the side.

The finished article. A hole has now been gently tapped through the flowerpot.

I made a thick metal plate with lots of holes in it that sat on that rim at the bottom and above the air hole.

Let the whole thing dry for a week and fire it up without a blower to dry it out.

I use a leather apron, welders gloves and full face headgear when using it. Good to be safe.

I did a modification to a hair drier and it worked reasonably well but wasn't shoving enough air through really. I was running the motor on a variable power supply so I turned the voltage up a little. The motor was happy but the plastic blades weren't and showed it by separating themselves from the fan hub.
I made a new brass fan and while it worked ok it was quite noisy and just didn't shove enough air through. Because the adaptor at the end of the drier was flat faced the backwash of air was coming back through the edge of the fan. As much coming out back as out the front, almost.

So what did I do? I built a cetrifugal blower that really slings air out for its small size. Click the link from the home page to see it.

The furnace running. It took 10 minutes from this point to melt the aluminium. It took longer to get the charcoal going thanks to the poor volume of air going through it. Can't wait to try the new blower.

Note that there is no lid and a fair amount of charcoal is used. Once finished with it stays burning for hours. Get a grill and do some burgers and sausages with whats left burning.

The flowerpot sort of demised itself (ok, it eventually fell out in tiny little bits). What I did was to get some aviary wire mesh and made it into a tube that I inserted into the furnace. I then mixed some thickish pure Portland cement and pressed it through the wire to build a new wall. The top of the wire bends over to reinforce the top of the furnace.

If you look carefully you can see the wire.

Also, becuase the sides are now straight, it takes less charcoal to fuel it.

 

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