The Shop > Metal Stuff
Foundry Furnace for the Tiny Shop
Will_D:
Steve,
Thanks for all the info!
I will certainlt start a thread when I start to build!
vtsteam:
You're welcome Will!
Oops, forgot one thing, there is an online source of casting info that I keep going back to, because it is pure gold. Anything filmed or written by Ironman you can take to the bank! :bow:
Eugene:
Will,
In other threads Steve has shown some of the castings he's made using the lost foam method; they look very smart.
You don't need anything fancy for the mould medium, just dry sand. That's certainly the way I'll go to start with, as initially my requirements will be for relatively simple parts, and one off, so making really super duper wooden patterns isn't on. I've hammered a foam cutter together and had a play with it ... doddle.
Gas tank (Polish!) that's been full of water all winter, a fire extinguisher body for a crucible, box section steel for a trolley, and some ally wheels and pistons are all to hand. I won't be starting for a couple of months yet, I've got other stuff to do, and it might have stopped raining by then.
Eugene
vtsteam:
Having done some lost foam casting, and shown it here, I have to admit, I don't like it, though, and I'd strongly recommend that anyone starting out just go with the basics -- greensand casting from whatever source you can make it. The bottom line is it is sand and clay. Practically any type locally available will do. There are high tech and low tech versions of it, but I think for beginning aluminum casting at relatively low temperatures what you have most easily available will be fine. As I said above, bentonite is nice, but not required, and I've done all of my aluminum casting with fire clay and sand.
What I don't like about lost foam:
You need a new pattern for every part you make
It takes at least a day of prep -- coating, drying time
if you've gated wrong you can't just repour in twenty minutes as you can with greensand.
the fumes are bad -- flaming polystyrene
it's very iffy -- tough to achieve consistency
you need very hot metal -- borderline oxidizing
it requires a greater head pressure, sprue extensions
sprue extensions pick up the loose un-bonded sand so re-melting sprues means sand in the melt.
the good:
Relatively thin sections are possible
surface finish can be great
no need for pattern draft
I don't think I'll be doing much more lost foam casting -- there may be an occasional reason to, but I'd say my success ratio with it is 25-30%. I do tend to use it for very thin sections, which is a challenge, but why bother with lost foam for a heavy sectioned part? My success rate for greensand aluminum is probably 90%. And it's quick to re-group, re-pour with different gating, and the results of a bad pour can be re-melted without sand contamination.
Anyway, that's just my own experience. Others may find otherwise... :beer:
Will_D:
And yet another question:
Why does no-one melt and cast low carbon steel?
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