New Member From Australia

Hi gang, thanks for letting me in. I'm here sooner than I thought I'd be too.

I've wanted to have a go at casting metal for ages but at the moment my life's pretty full. I'm restoring an old bike, work full time, have my own little powder coating business on the side, play in a band and have a big yard to maintain so thought I'll get around to casting one day - well, getting around to building a forge one day. In the mean time, I've been collecting aluminium and copper for when that day arrives. Recently, we had a huge clean up around our place and had a skip on site. My wife asked if the two 44s full of "metal and sh*t" (scrap aluminium) were to go in the skip. Lol, I explained to her why I'd been collecting it and that when I had time to build a forge, I'd start melting it all down. She wasn't real happy with that answer as even though the 44s are behind my shed, they annoy her.

After dinner that night, I opened FB on my phone and literally the first thing I saw was an ad for Devil Forge. I chuckled and showed my wife saying something about how our phones listen to us. She asked how much it was and I said around $450 for a 10kg unit and she asked if I wanted one for my birthday. I said that it was a sh*t ton of money to spend on a birthday prezzie but she said "yes, but then you could get rid of all that metal".

So, there's a 10kg Devil Forge in transit as I type this.

I have questions. Many questions...

 

Hi Wayne, welcome to the forum from someone in North Queensland. The Devil Forges are pretty good for what they are: a naturally aspirated small furnace. It'll be enough to let you get up to speed with melting aluminium and copper alloys. Do you have something specific in mind to cast like bike parts?. Making aluminium ingots will give you a compact stack but ideally you'd have some finished object to cast (preferably something the wife needs or can readily sell). You may get a hankering later on for something with a bit more grunt and larger capacity at which point you'll be looking to build a forced air furnace using real high temperature bricks from somebody like Foseco (not the bricks sold for pizza ovens) or high temperature dense concrete from companies like Foseco or Refractech.

 

Welcome to the nut house.
Not even the guy at DF knows what to call his furnace. And yes, it's way overpriced for what you are going to get.
On the plus side, it's done and ready to go to work. Average build time for a furnace around these parts is a month or two.

Here is lesson one for ya.

 

Thanks Mark. At this stage I'll be happy to reduce the mountain of scrap down to ingots. I have nothing specific I want to cast although I'm sure I'll come up with stuff once I start messing with it all. My main question at the moment is where do you get crucibles and ingot molds? I could fab up some molds but are there any "rules" for making molds? Material thickness, shape, calculating volume etc.

Lol, thanks Jason. Yes, it was expensive but it saves me the time of making something similar and as you say, it'll be ready to work.

 

Welcome Wayne,
Yup, by all appearances the devil forge will get you going. I have to go along with Mark about setting some casting goals. Plaques, decorations, repairs, parts, tools. We cast a lot of different stuff, and melting for the sake of melting gets old pretty quick. What's more, once your scrap is no longer in its original form it's alloy becomes unknown and its scrap value diminishes to the bottom of the chart.
There's a lot to learn about procedures, tools, PPE, etc and lots of discussion about those things here. YouTube can be very helpful but beware the clown shows.

Pete

 

Thanks Pete. I've already been watching loads of vids. Lol, there are some are clowns out there

 

Shorts and flip flops should be your first clue.

 

Rule number one for metal ingot moulds: always preheat them over the furnace exhaust to drive off any moisture in the surface. If you pour into a cold ingot that's sat for months on the workshop floor, it's guaranteed to flash surface moisture off to steam with a splatter of hot metal. I was wearing a plastic face shield for grinding while casting bronze and the excess bronze went into a cold ingot mold... some moisture flashed off to steam and a bronze splat the size of a five cent piece appeared on the shield right over my left eyeball for an instant before disappearing with a loud crack!. After everything was shut down I examined the face shield and found a clean spot on the dusty plastic shield, the bronze must have hit the mask, vapourized the surface dust which blew off the bronze before the plastic could even be damaged.

So again... preheat your steel ingot moulds . I made a batch of three ingot moulds recently with a short lengths of steel channel, the sides were parallel which is no good so I placed them lengthways on a larger diameter steel pipe and whacked them with a sledgehammer to get some draft on the sides to aid ingot release when solid. As for crucibles, you can buy Vesuvius brand from Foseco and Morgan from Skamol in Melbourne.

 

And rust up your molds in salt / damp conditions before preheating and using unless you want the ingot to weld itself into the clean metal mold.

 

Thanks for the tips guys. I knew about preheating the molds before pouring but what sort of rust layer do you mean Zapins? Just a flash rust? We have a nasty old hydraulic press at work which sounds a bit easier than using a sledge hammer Mark but I appreciate the heads about about the channel. Are there any other pitfalls to avoid in making molds?

I'm good with safety. Most of my life I spent working on military aircraft and safety was drummed into us long before Health and Safety became a university subject. In regards to playing with liquid metal, I'll be straight on here if I don't know how to do something. As for shorts and thongs, I would at least wear my welding jacket with shorts and thongs...

I'll check Skamol out too, thanks mate.

 

Throw some salt and a cup of water into a bucket and slosh it around over the metal then let it sit closed up for a day or two to rust the surface. This will get you a nice surface rust layer that protects the metal from sticking to liquid bronze/copper alloys. Thats what I do with new molds anyways.

 

Good to know, thanks.

 

A lot of guys use muffin tins. I advise not to raid the good ones in the kitchen or the missus may find the furnace useful for roasting nuts lol. Buy clay graphite crucibles.Morgans are most likley one of the best. I got a 8kg off evil bay ages ago still going awesome. I recently purchaced an A25 Super salamander. Now have to convince my missus to help with it .

 

My wife doesn't do much baking so I doubt she'd miss much from the kitchen lol. Does the 8kg crucible reflect its capacity for aluminium or copper etc?

 

Avoid Teflon coated tins. It's extremely toxic. Crucibles seem to be generally in kg of copper but types and manufactures vary so check the mfg specs. If the seller doesn't say what it is then chances are you don't want to buy from them anyway. Mark's Castings or Ironsides should be able to direct you to a good supplier.

Pete

 

I heard a firsthand account of melting a lot of scrap red brass / bronze gas cylinder valves from scrap oxy and acetylene clyinders with teflon valve seats: it generated a very toxic gas that nearly put the foundry workers in hospital. Not too sure what the resultant gas is.

https://en.wikipedia.org/wiki/Polymer_fume_fever

 

Take it for what it's worth:
https://www.ewg.org/research/canaries-kitchen

 

Top tip with the Teflon I can fab up some ingot molds easily enough

 

I never thought about crucible sizes being in kilograms. That makes more sense than a A10 holds 10lbs of aluminum or roughly 3x in brass or bronze.