Here we go...(the long way) casting aluminium.

[artyone]

Be Warned... I go on for ages and hardly say anything, and there's no pictures. (but there is a video link though even that is almost as boring as I am, maybe even more so!)

 

I've been around the edges of this for years but recently a friend has gotten around, after I gave him a solid and dependable small cast iron pot, to melting Zinc in his fireplace then carrying it through the house and pouring it into still not dry plaster molds. The results are incredibly bad... but he's an artist so they're actually quite good because they're so bad.

 

Before I gave him the cast iron pot he was using a tin can and melting whatever he could find and really getting nowhere fast and making lots of quite lovely messy half melted ingots and huge piles of slag... hilarious and completely dangerous.

 

At one stage his computer was so broken I had to find him a good working laptop for 140 bucks then install the Ubuntu operating system and fiddle about just so I could show him a video or two of how simple aluminium casting can be and when these vids were finally rolling, after his weeks and weeks of experimenting with whatever was at hand, he turned into a five year old with a grin that almost split his head open!

 

But he's kept the same old practises up and even yesterday after telling his sister about his escapades she passed on the information that the fumes from Zinc were incredibly dangerous and full of Ammonia and Arsenic... what?

 

Anyways, it's time I actually got around to it myself. It's partly to show him how to do things the easy way without wrecking his whole do it like a caveman ideal which is actually creating some quite bizarre pieces but it's mostly because I've been skirting around the edges so long I should really get doing it myself.

 

My brother got into having a whole bunch of wax models he made cast in bronze and I've had stuff cast in aluminium, sand cast, and pewter, silicon molds and spin cast, when I was into electronics then did a year at school with clay and all that big fire stuff so with all this it's almost that I have to actually melt some metal myself.

 

Typically though, even while I have a couple of ceramic crucibles and a good collection of small cast iron pots, I'm going to make my own crucibles. While doing clay those coupla years ago a mate in Riverhead mentioned the clay there was white so I grabbed some and got it fired. The thing was that at even the highest clay temperatures it wasn't vitrifying which kinda told me it'd be a nice refractory clay.

 

So you've gotten this far and realised, my God, get to the point!!!, but sorry, I like writing and all navel gazing activities so either get frustrated and throw something across the room and curse me to all the old Gods you can think of... or take a deep breathe and dive back in....

 

Typically I don't want to just do what I'm told though I really do like this fellow's way of doing things.

https://www.youtube.com/watch?v=E3my6-nxFjM

 

I'm going to add a few things to the clay I've got from riverhead and one of those is Vermiculite (Vermiculite is the geological name given to a group of hydrated laminar minerals which are aluminium-iron-magnesium silicates, resembling mica in appearance) which I've used before mixed with sand and cement to build sculptures and noticed that written on it's packaging is that whilst also being fed to cows as a feed suppliment... is a refractory.

 

I'm also going to throw in a little silica sand and some alumina (aluminium oxide) as the addition of extra silica will require a flux to bring down the melting temperature or vitrification. Why, simply to see whether the stuff I learnt at clay school, a kind of intuitive sense about mud, might actually work.

[flyingbrick]

Very cool dude! I'll watch videos tonight when at home. Id love to give that a go sometime too.

Don't forget the ability to 3d complex parts in plastic to provide relief in your sand.. There's guys here that would help if needed I'm sure!

Have u seen the anthill casting?

[SOHC]

You can buy clay graphite crucibles for around $30 for an A8 size witch holds 8 kgs of bronze

[Guypie]

Good to see somone else on the metal melting bandwagon. I will post up pics of my budget as home made furnace when its finished, prob get it done this weekend.

As for zinc, it is safe as long as you dont get it too hot, the fumes if it does get too hot are visible (white or yellow smoke) and it is zinc oxide, which will make you sick but not arsenic sick. Also with a chimney any traces of fumes at low temp will be taken in by the pull of the chimney. As for the slag i read that calcium chloride is a good flux for zinc, and it is sold cheap as chips as pool water hardener.

This website has heaps of info, it is very dry reading but super handy for all sorts of metalurgical info

http://www.keytometals.com/page.aspx?ID=MaterialBasics&LN=EN

[SOHC]

If you need graphite or sodium silicate, I have heeps of it, you could use the sodium silicate to bind some kind of refractory together

[artyone]

Cheers for the replies chaps and this way of doing things is something that works best for me. It's not that I couldn't do it the graphite way, as my ears have already perked at that, but that right now this is stuff I already have lying about and I love making a small amount of stuff do a lot of work.

 

But later on, for sure, I'll be more practical but for the moment just building a space to do this stuff in and set up a small grate and fire box with a chimney of some sort and making a bunch of tongs and stuff outta rod will be more than enough to get me started. I'd already picked up a garden blower for forced air but that way too much and today, while down in Morrinsville, I picked up a small hair dryer which with the element removed will be just the job.

 

That anthill videos was the first one I showed to my friend actually... it was so amazing, poor ants though, Ant Hiroshima!

 

And I told him about Zinc oxide as I've done a little welding of galv and it's an ass but what I was trying to get through to him is that a little research and a little knowledge foils superstition and ignorance. "Buddy, Zinc is an element and so is Arsenic and why might there be Arsenic in Zinc... yes there are alloys of Zinc but I doubt Arsenic would be one." He's a brilliant artist and I admire the find and make do ideal, as I have it myself, but real knowledge and expertise handed down over thousands of years... should not be ignored.

 

I've been building models for years, of this and that, in various materials and one I have is a two part resin, like knead it and the other similar stuff, except this one takes about 8 hours to harden so the window to work it is really wide. You can fashion it just by hand for about two hours and then as it gets harder start using blunt tools and that good for at least another hour then  knives work really well as it's rigid but still a bit soft till eventually it goes hard as a rock and it can only be filed and sanded... wonderful stuff, then there super sculpy which is really workable too but will only really harden in the oven. Plus I have all my carving chisels and can even go the old fashioned way and use wood.

 

Three D modelling just doesn't appeal as much as actually having something in my hands to play with.

 

One of the first thing I wanna do is make new covers for the CT110 engine I got from Japnut. Covered with little heads, eyes and faces and other silly stuff which I can then bolt on to replace the exiting ones. Then work my way up to doing inlet manifolds... which are like tree trunks! or maybe Art Deco.