Wednesday, July 22, 2015

Episode 6: Homebuilt Foundry

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Charcoal Foundry by David J. Gingery

Ornamental Metal Casting by R. E. Whitmore

Photos of the build process:

Here's the metal bucket I used.


Measuring for the tuyere hole, that's in inches not CM.


The bucket after the tuyere hole was drilled.

The pattern for the tube to form the inside of the foundry.  I used a pot lid that happened to be the right size as my template for drawing the circle.


The circle, with the design for the handle to make it easy to remove.  The holes were drilled so I could get the saw blade into the board, which was a 1x12.


The holes finished.


The hole for the one side of the handle cut out.


The other hole cut out.


The handle cut out completely.


The pattern for the bottom tube form.


The form cut out, with a screw drilled into to make it easy to remove the bottom when it came time to remove it from the foundry.


Making the tube form.  I screwed up and cut it wrong, so I wound up 'mummifying' it with duct tape to correct this, since I didn't have any spare flashing metal to make up a new one.


The finished tube form, wrapped with duct tape and with screws to hold it in place.


Top view of the tube form.


Seating it in the bucket.


This is the outer ring of the lid.


Side view of the lid, showing the holes for the handle.


Form for the inside of the lid, to be the vent hole for the foundry.


Holes punched in to allow the re-enforcement wires to pass through.


The finished lid, showing the wires and rebar handle in place, before the concrete is poured in.


Another view of the lid.  As you can see, the wires pass through the hole, this is fine, and you don't have to worry about removing them.


Air pipe or tuyere pipe.


The pipe installed in the foundry.


Looking down inside the foundry with the pipe in place.  I put some cardboard between the pipe and the wall of the bucket to keep the concrete from leaking out when I put it in.


Readying the bucket to have the rest of the concrete poured into it.  I've already poured in the bottom layer of concrete.  The boards sticking up are the spacer boards.


The lid after it was filled with concrete.


Hair dryer modified to use with the foundry as an air source.  It works, but its less than ideal.  It also has a heat switch inside the barrel, and you should disconnect that, as it will cause the hairdryer to cut off at inopportune moments.


The tube after I removed it from the foundry a week after I poured in the concrete.  I didn't put enough oil on it, so it was hard to get out.



Burning some wood in the foundry to help dry out the concrete.



This is the crucible filled with aluminum cans before the first heat.


The foundry put together and ready for use.


Side view showing how the lid fits on the foundry.


Charcoal being put into the foundry.


The end result.



The 'Grabber' used to pull the crucible/pot out of the foundry.


Dump hook.


Side view of the crucible, showing the 'J' holes, and the dump loop.  Use a smaller loop if at all possible.  Mine's a bit larger than it should be.  The piece of metal you see above it is the end of the dump hook that's used to pour the metal out.


Inside the foundry after I poured, showing the leftover charcoal.


The hand vacuum I now use to provide air for the foundry.  This works beautifully.


A foot switch that the vacuum cleaner is plugged into so I can easily turn it off and on.


The 'Grabber' with tape on one end of it to use as a handle.  I found out the hard way that this is good idea.



Video of the foundry in operation:




That's a plaster mold I placed on top of it to warm it up before I poured metal into it.

The foundry running, using coal instead of charcoal.


Here's the magnesium that caught fire on me, after I'd fished it out of the crucible and covered it with sand.


The box of coal I bought for $20 on eBay, I only needed about 2 scoops to get it hot enough.



Note that in some of the pictures I didn't have any sand down.  This turned out to be a problem when I ran the lawnmower, as it found all the little pieces of metal I missed and flung them against the house.  I quit playing with the foundry until I could get enough sand to have several centimeters on the ground.  That way I wouldn't have to worry about the mower hitting anything, and as I mentioned in the podcast, it came in handy when I accidentally tried to melt some magnesium.

An alternative design for a foundry.

I'm not a huge fan of that design, since it seems like it would be wasteful of charcoal, but I think the design for the crucible is interesting, though I wouldn't use an old propane bottle as my source for the metal.

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DIY water filtration kit.

Clean cooking catalog.

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