Gingery Lathe - Metal Sand Casting

[dlavery]

Sandrag -

If you really want to get into sand casting and making your own parts, systems, and even complete machines from scratch, go for it! It can be a lot of fun, and you will learn an incredible amount about everything from metallurgy to structural design to machining techniques. But let me offer a few words of advice (which is always worth what you pay for it):

- read EVERYTHING you can get your hands on about the topic. There is a lot of information out there - use it! Check out the "Forges and Foundries" section of the Metalworking Web Sites Index for lots of info. Gingery's designs are pretty slick, but his methods are not the only way to put together a home foundry - some of the other designs you will read about are higher efficiency, cheaper to build/run, easier to make, etc. Check them out as alternatives.

- Once you have read up on the info, find someone who has or works in a small foundry, and spend a day talking to them and looking over their shoulder. You can spend weeks reading about the proper consistency of green sand, and still not really understand what it should be like. Or you can spend ten minutes with someone that really knows, and they will shove your hand in a pile of properly tempered sand and you will get a real "feel" for what it should be like.

- Pick a design, or make up one of your own based on what you have learned, gather the parts, and build your foundry!

- Before you fire it up for the first time, stop, take a step back, and think very carefully about what you are about to do. Is it safe? Do you feel comfortable with the quality of the design, the construction, and how to operate the foundry? Is it safe? Is the area around the foundry clear of hazards? Is it safe? Are you properly prepared if something goes wrong? Is it safe? Do you KNOW what can go wrong, and how to handle it? Is it safe? Do you have the proper clothing, equipment, supplies, and set-up to handle molten metal? Is it safe? (do you catch a theme here?)

- Molten aluminum, or if you go beyond that to molten brass, is nothing to fool around with. If you make a big mistake here, you can kill yourself or someone around you. Please, please, be very careful.

OK, end of lecture. Making up molds and casting your own parts can be great. You can do it very cheaply as well - I built my foundry out of an old 20-gallon oil drum I found in the woods, some scrap pieces of plumbing pipe, a few brass fittings from Home Depot, and some ceramic wool kiln liner from the local ceramics shop. It burns propane (instead of charcoal as in the Gingery design), is naturally aspirated (instead of needing a blower), and whole thing cost less than $100 including the propane pressure regulator. It is big enough to handle a #10 crucible, and the biggest pour I have done was about 18 pounds of brass for a lathe faceplate casting. Here is a photo of the completed foundry, and the burner during the first test firing:



(note: these photos are of a test firing of the burner, not of an active molten pour. Never pour metal on a concrete floor - if the metal spills on the concrete, it can cause the minute amounts of trapped water in the concrete to flash to steam and cause the concrete to spall and explode.)

There are special side benefits to having your own foundry in your garage. First off, periodically having a 2-foot-long jet of blue flame squirting out of the garage door in the middle of the night tends to keep nosy neighbors away. Second, when you get hungry in the middle of the night 'cause you forgot to eat all day while you were working on your robot, roasting a hot dog takes about 14 seconds! But the best part is that you can make custom parts for your FIRST robot. We used the foundry two years ago to make cast motor mounts for the older 3/8" Bosch drill motors. The team learned a lot and we had something unique on our robot that year that we KNEW no other team would have - custom cast motor mounts. But the very best part was that we were able to REALLY recycle robots from prior years - by melting them down and pouring them into molds for the new parts!!!

-dave