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A very simple furnace for breaking down wheels

Posted: Mon Aug 08, 2011 11:41 pm
by barryjyoung
After building our crucible furnaces which will just barely admit a #20 silicon carbide crucible, we realized that a car wheel was never going to fit. No problem, we have a sawzall. One unfinished cut convinced us that was way too much work. The only answer was another furnace. We had already spent way more money than we wanted to in making the crucible furnaces. If we were to make a break down furnace, it was going to have to be cheap. We found some fire brick that was a little less than perfect for a couple bucks each. We made a big box out of the bricks that would hold a 22 inch car rim. The bottom was lined with two pieces of broken kiln shelf that we got way cheap from the local pottery and clay vendor. The lid was cast from 3200 degree refractory inside a welded angle iron frame cut out of bed rails from the thrift store. We lined the frame with plastic packaging material from the garbage and laid on a piece of used plywood. After the lid had set, I welded a frame of 1/2 inch angle iron around the box of bricks to make a frame that I could weld some supports to underneath to support the floor bricks. This frame kind of holds the whole thing together. I welded some wheels from a $5 yard sale hand truck on the back and put a folding handle made of Electrical EMT conduit (Real Cheap) from Home Depot on the front. I used a nasty old concrete block to counterweight the lid and welded some used hinges in place. I drilled through the firebrick on the back and welded in a burner holder to accept the Ron Riel burner from my crucible furnace. It melted 14 car wheels in 4 hours into five pound ingots. I am going to use five gallons of high temp refractory I got for free to coat it inside and out though it works just fine without it. Hope this build might help some of those of you who are still breaking down wheels in the BBQ. Let me know if I forgot anything.

Barry

Re: A very simple furnace for breaking down wheels

Posted: Tue Aug 09, 2011 7:48 am
by blindpig
Good job!
Love fabricating(repurposing as it's called now)stuff from low cost or better no cost materials.Inexpensive way to "git er done"and looks like it's working as intended.

Re: A very simple furnace for breaking down wheels

Posted: Tue Aug 09, 2011 10:07 am
by Harry
Barry how does it drain off the melted metal? Is there some sort of pool that forms and you can tilt it when you want to pour or is it just a drip when it is ready?

That is a respectable rate on the melting, I figure 18 lbs per wheel so just over 250 lbs in 4 hours isnt bad at all. As I mentioned in the other thread I love working with A356, the alloy is a very good fit with most everything I cast. That is quite a nice stash of ingots too, do you have a particular project in mind, current casting needs or just stocking up? If you are doing 250 lbs on any sort of regular basis you are likely also producing a lot of castings.

Re: A very simple furnace for breaking down wheels

Posted: Tue Aug 09, 2011 5:10 pm
by Jammer
I was trying to think how much metal he may have ended up with. Kind of looks like it just runs out the bottom as it melts.
Good job on the build.

Re: A very simple furnace for breaking down wheels

Posted: Wed Aug 10, 2011 1:36 am
by barryjyoung
Thanks guys.

Blindpig: Me too. I am a scrounge.

Harry: The molten metal drips down through a slot in the bottom left between the kiln shelves. Sometimes you have to poke the slag blanket that develops. The resultant ingots are not terribly pure or clean, but they will be after skimming in the crucible furnace. As to projects, I have it in mind to make very big cameras. That was the whole reason for building a machine shop and foundry. I have not yet produced any castings. Hopefully soon. I only get an average of 14 pounds per wheel. I also melted 20 photo enlargers that day. Would that be enlargium?

Jammer: 254 pounds including the enlargers.

Here is the stack of ingots from the last melt.

Barry

Re: A very simple furnace for breaking down wheels

Posted: Wed Aug 10, 2011 1:47 am
by mite5255
Nice stack of ingots, but I must ask, what do you do with all those g clamps, looks like you've cornered the market :)

Mike

Re: A very simple furnace for breaking down wheels

Posted: Wed Aug 10, 2011 1:53 am
by barryjyoung
mite5255 wrote:Nice stack of ingots, but I must ask, what do you do with all those g clamps, looks like you've cornered the market :)

Mike
Hi Mike:

Thanks.

Well, the guy at the woodworking store said over the loudspeaker that he needed to get rid of all those clamps on that table in the center of the store and he would sell them four for a dollar. So I bought them all. What you see is less than a quarter of them. I use them to build wooden cameras.

Barry

Re: A very simple furnace for breaking down wheels

Posted: Wed Aug 10, 2011 2:02 am
by mite5255
Wow love to see one,ummmm I'm assuming they're not digital camera's :roll:

Mike

Re: A very simple furnace for breaking down wheels

Posted: Wed Aug 10, 2011 6:21 am
by Jammer
Image

This is a camera used to take pictures of an X-ray I'm trying to turn it into a small CNC machine, that project has stalled for the moment. :( It' upside down in the first pic.
Are you building large format cameras like Speed Graphics, or bigger than that?

Image

Re: A very simple furnace for breaking down wheels

Posted: Wed Aug 10, 2011 10:58 am
by barryjyoung
Mike: There are no pictures yet, because nobody has ever made a folding field camera from aluminum before, but they will look a lot like the wooden camera made by Ron Wisner in this picture. They can take a digital back, but the object is the finest image possible so there would be very little point in putting a digital back on them, that would be like putting a 64 VW bug engine in a Rolls Royce. Film has far far greater resolution than digital CCD or CMOS sensors. So imagine the camera shown except in aluminum and larger. That is the best I can do right now.

Jammer: Nice start on a CNC machine. When I built my CNC router I took the very easiest route I could, I bought a kit from Xylotex. This was pretty much turnkey and I had the motors operating on my kitchen table the first day. That was a kit purchased to convert my Grizzly minimill. Once I got that running I needed more travel so I designed a weldment with 6 feet of X travel, 12 inches of Y and 10 inches of Z. After building the monster and a nice bench on which it lives, I took the head from the minimill and mounted it to a plate which bolts onto the Z axis. I have another plate that holds a 2 HP Porter Cable router. These plates can be fastened in different heights in case 10 inches is not enough Z. Good luck on your CNC project, it is SO worth the effort.

Barry