Casting Help

I have been saving aluminium, i have some good quality stuff from some old computer hard drives and some casted aluminium. I want to melt it down to make some billets to turn. What is the best type of aluminium for doing this. What are peoples experiences of melting ally.

It's a bit like making ice cream,.......the recipe is simple enough and the ingredients are easy to find, however, just like ice cream it;s MUCH more difficult to make something really good and successful. There are lots of little details that need to be in the forefront of the casters (and ice cream mixers) mind for success.

..............For a beginner you can do no better than to go on YouTube and look at the videos of 'Myfordboy' and all might be revealed......

There are a couple of books including the workshop series ...;backyard casting' (?) and the little book by B Terry Aspin.     However, 'Myfordboy' is probably just as instructive and easier to absorb.

Edited By Bob Stevenson on 15/06/2017 00:13:30

Apart from the satisfaction of doing it, wouldn't it be easier to trot along to your local aluminium shop and buy a lump of 6061 T6, or the local equivalent. At least you will know that it will machine well. Making a few billets of "home grown" aluminium may present you with a few challenges as the material will be likely to be dead soft as in annealed and machine a bit like porridge, all soft and clingy.

Best of luck!!

cheers

Bill

I usually cast bronze but have done a few aluminium castings. I used old alloy car wheels, which should be a good quality ally, but the resultant casting machines very poorly. As Bill said 'soft and clingy' and it was full of gas bubbles. Ok for the application (a bed for a model steam engine). Again, as bill said, buy some 6061. Rather expensive, but a much better aluminium.

Not tried it but there are comments that alloy wheels make good recycling alloy, as they are generally a good, well controlled item in the first place.

Even if you did melt down 6081 T6 you could still end up with a gummy casting as they really need heat treatment afterwards to get a nice machinable casting. You would loose the T6 part by remelting it.

"gummy" or porous castings have nothing to do with basic integrity of the metal, they are because the molten metal was not de-gassed. Just one of the many little details that you need to know about.

Have a look at MEW Issue 110 Nov 2005. There is a full article detailing aluminium casting and aluminium properties. I think there is a part 2 a little later on but you can look for that.

regards Martin

Having worked for an aluminium casting foundry for a few years I can assure you it is not a simple process.

I melt mixed aluminium waste to make castings. The material usually turns OK for machining. The only time I have had a problem with gummy material was when I melted only aluminium extrusions (old double glazing frames) and this material was quite soft and gummy. Gummy aluminium can be improved by dissolving 1 or 2 % copper in the melt.

To get good clean castings then it is important to remove as much slag as possible from the melt. To do this I add LoSalt (a mixture of sodium and potassium chloride for people on low salt diets - available in most supermarkets) as a flux. This is stirred into the molten metal and it brings all the slag to the top where it can be scraped off.

Mike

Take a look at this site: **LINK**

Lionel has an 'interesting' attitude to safety, particularly with his crane, but with the inspiration from that site and Colin Peck's ( **LINK** , I did my own little furnace - **LINK** . My page hasn't been updated in years. The 3 year old daughter I mention is now taking her 'A' Levels...

The aluminium I have in abundance is LM4 and a bit of LM6. These are casting alloys and the latter is relatively machinable, though LM4 can be machined too. Basically sift through your stuff & see if anything was machined after casting, and use that. Car engine crank cases will be good, electric motor frames, that sort of thing.

Regards,

Richard.

Of course if it were really aluminium - it would be soft and mostly useless

Regarding engine casings, and alloy wheels - just keep an eye out for any magnesium alloys as I gather they can get a bit ferocious being over 90% magnesium! I remember thinking to myself, I must look in to this before getting too carried away myself.

I believe you can distinguish a mag alloy from an aluminium alloy by its density (using a bucket of water seems popular) - and if your good enough at it, you can even take a stab at what grade the aluminium is, assuming its conforms to a standard (so, this doesn't work for anything of questionable quality)

I have done a fair amount of aluminium casting in the past. I used car pistons as a source material. Provided you follow the instructions to the letter from say Terry Aspins book. You will be rewarded with decent aluminium castings, that machine well. Any deviation from the rules and you are on your own. It isn't difficult but you will need to buy some "wash" to coat your melting pot and also some material to chuck in to help remove the dross.

Andrew.

The mention of magnesium brought back a memory of aluminium casting. We used to make some of the handles for Bridgeport milling machines right from casting to finished part and as an apprentice I was watching the melt and decided to add a few pieces to the melt pot! I mistook magnesium for aluminium and the flare fire that took place was intense. We took the pot 0utside and dropped it into the skip but it set fire to the metal swarf and the fire brigade had problems putting out because they couldn't use water as it reacted with that sort of fire. I didnt do any casting from then on.

David

Thank you all for the comments and your experiences. I am new to lathe work and casting. I have run lots of drums and discs off on a lathe but noting else so I thought it was about time I did some learning. My daughter wants to be an engineer and loves to help me when I am in the garage and workshop. I don't always have funds to go out and purchase new material hence, making my own. I do have access to car parts and computer hard drives which I am told is a good quality aluminium. I have seen a few videos that do add salt to the mix to which I thought was to degas it. To be honest, I did like the light the magnesium in school, however I think a full wheel may be pushing it a bit and I would like to keep my workshop. It has taken me 33 years to aquire a lathe of my own! I kind of get the feeling, it's all down to the quality of the metal and how you process it. Thank you for the links and advice on books, I will certainly take everyone's comments on board.

Is there an easier metal to Cast that would be good to test the waters with? I want to make a stationary steam engine, well that's the goal in mind.

Any more advice on this would be much appreciated.

Have a good evening ladies and gents.

I think in terms of an actual usable metal, aluminium is probably your best bet.

You can get lower melting alloys used for die making, fixing, pipe bending among other things, I've purchased from **LINK** with ease.

If your as intrigued by new processes as me, check out their low melt plastic too which is water soluble - I've got half a kilo but I've yet to play with it as I've been too busy with other things! I'm going to be building new liquid cooled PC in a month or 2 and I quiet fancy making use of this stuff for no reason other than to have a play with it.