Home made cast Aluminium

[ChrisBParticipant @chrisb35596]

Hi there, watched a couple of youtube videos of people casting aluminium but one caught my eye as it involves casting the material to be used instead of round stock. From what I can see in his videos, it does not take much to do and the resulting material seems to machine well with no noticeable internal defects.

Would that be something you would consider doing? I mean is it worth the time and money?

Edit Links Removed, see Code of Conduct

Edited By JasonB on 25/08/2020 10:37:28

[ChrisBParticipant @chrisb35596]

Is it good/worthwhile

[Bob StevensonParticipant @bobstevenson13909]

I think it's debatable whether it's worth doing for cylindrical stock to turn,……if the resulting cast "machines well" that's because the donated metal was good quality with no spurious additions. If you buy from a reputable metal stockholder you can be sure of the quality of your alloy,….an important issue if you are making something serious.

When it comes to the casing of ally alloy parts which are NOT cylindrical but shaped for the job then, then you are on a more stable footing. lots of small machines and other projects can be made up using unspecified ally o provide worthwhile castings….what's not to like?…..these parts would be extremely expensive to have made by an outside source.

[EmgeeParticipant @emgee]

Most casting shapes can be replicated with cnc machining but can take many hours using very small cutters, the benefit is the material is of known quality.
Castings can also be made from known specification materials but will not be such low cost.

If you have the facility and a supply of known cast al material it may be worth trying.

Emgee

[ChrisBParticipant @chrisb35596]

They gentleman in the video mostly uses scrapped alloy wheels, which I would expect to be a fairly decent material, another good source could be vehicle cylinder heads. Surely not soda cans etc.

If we had to compare like with like, say 6061 alloy, I would expect the scrap cast alloy to be inferior to the shop bought material as the temper state of the cast alloy would be unknown. But if the material is not needed for some specific job where it's properties really matter, then I see a good reason for the diy route. The only deciding factor remains the cost. If the material can be obtained for free, the cost would be the amount of energy/fuel used to melt it.

[Nick WheelerParticipant @nickwheeler]

Posted by ChrisB on 25/08/2020 11:30:37:

If we had to compare like with like, say 6061 alloy, I would expect the scrap cast alloy to be inferior to the shop bought material as the temper state of the cast alloy would be unknown. But if the material is not needed for some specific job where it's properties really matter, then I see a good reason for the diy route. The only deciding factor remains the cost. If the material can be obtained for free, the cost would be the amount of energy/fuel used to melt it.

You have to count the extra time and hassle of making the 'casting'. Plus the extra time of roughing out to start machining it.

I can see why you would cast shaped parts, especially if using small machines, and intend to try it. but making your own round/square stock

[ChrisBParticipant @chrisb35596]

Posted by Nicholas Wheeler 1 on 25/08/2020 11:34:57:

You have to count the extra time and hassle of making the 'casting'. Plus the extra time of roughing out to start machining it.

I can see why you would cast shaped parts, especially if using small machines, and intend to try it. but making your own round/square stock

The casting form used in the video is just a seamless steel tube, simple enough. The alu contracts and releases from the steel form. It would be another story if it were sand casting tho, as you say not worth the effort for round/square stock.

I also think this would be more appropriate for a large diameter piece of stock which would be pretty expensive to buy (at least locally)

[I.M. OUTAHEREParticipant @i-m-outahere]

That video tweaked my interest also !

A simple furnace made out of a paint tin lined with pearlite / cement mix , a crucible made from an old oil filter housing and the mold is just seem less steel pipe . From one mag wheel you get a fair bit of aluminium .

[JasonBModerator @jasonb]

You would also want to get your fluxing right and remove all the dross so that there are no inclusions or bubbles. Once setup it really comes down to the cost of the gas vs cost of bar if you can get the wheels for free and have time to spare.

[John ATTLEEParticipant @johnattlee20632]

I was working out how to make a thermostat housing for a 27 litre tank engine the other day. A 6" lens of 8 " dia round bar was unaffordable. I did the job by fabricating with steel and machining. If I could have cast something, never mind how roughly, I would have done so. The trouble is that it takes time to develop the facility and it was not worth it.

Getting some good aluminium alloy casting as the raw material is easy and cheap provided that it is not a critical application.

I suspect that if one had the facility one would use it more and more.

John

[John HaineParticipant @johnhaine32865]

On a similar note, I am accumulating brass offcuts that are too small to use for other things – for example wheel crossings out, the outside of a square plate that has had a ratchet wheel removed from it. Given the price of machinable brass, has anyone any experience of melting brass down and recasting as bar? I'm slightly nervous about trying this as even soft soldering brass with a flame seems to de-zincify the surface.

[I.M. OUTAHEREParticipant @i-m-outahere]

The guy in the video ( Rob) doesn’t bother with flux , he keeps the temperature down to the bare minimum to melt the aluminium then scrapes the dross off and pours . He has been doing this for many years and has found a sweet spot that gives good results without de gassing . If you had a couple molds set up you could knock out quite a few castings in a couple of hours and the only cost is a few dollars for lpg and some time .

Getting short lengths of aluminium bar here in Australia is not difficult but can be expensive , here where i live in western sydney i have an hour round trip to my nearest supplier then i have to wait for them to cut it – if they are packing other orders you go into the queue its either that or Ebay and then you have postage and usually a few days wait until it arrives .

[Bob StevensonParticipant @bobstevenson13909]

I first made ally castings at school in the 60's during 'O' level metal work,…we made a pad saw handle and then a small table vice,…the harpoon guns were not 'curricular'…. There is a bloke by name Knowle Langley (?) who goes around model clubs demonstrating his great ability to cast ally and brass…the brass is much more difficult to get good results and the required temperature is considerably higher and more critical.

 

 

Edited By JasonB on 25/08/2020 13:10:03

[BazyleParticipant @bazyle]

A cast bar is likely to include slag and have some blowholes but for many pieces that doesn't matter. It is more likely to be casting something else, like an engine crankcase, and have some left over that you pour into a suitable mould. Lots of casters use pie tins ready for the excess so have little round bits that they probably use when they need a little wheel or bush.

However aluminium for good fluidity in casting has some silicon, up to about 5%. This reduces ductility in the product. Extrusions like window frames are fairly pure to facilitate the process but therefore less strong and gummy to machine. Sheet etc for engineering applications the typical "alloy" we glibly refer to has copper to provide strength, but this reduces its corrosiong resitance quite markedly especially if you are near the sea. Alloying elements also affect weldability.

So if you source your material from al over the place you can't be 100% sure of the product but for lots of things it woud be fine.

[Mike PooleParticipant @mikepoole82104]

Noel Shelley does demos at exhibitions and clubs.

Mike

[ChrisBParticipant @chrisb35596]

Posted by ChrisB on 25/08/2020 10:23:59:

Edit Links Removed, see Code of Conduct

Edited By JasonB on 25/08/2020 10:37:28

Not sure which part of the code of conduct did I break to have the linked videos removed…aren't we allowed to post youtube videos anymore?

[JasonBModerator @jasonb]

From the CoC, last line applies, the Youtuber reviews products from a certain source from what I could see

Posting links to unregulated sellers or ‘review videos’
While we understand that forum members want to discuss all aspects of the hobby,
we reserve the right to remove links or posts linking to sellers who may be
supplying goods not properly covered by UK safety or consumer legislation.
This includes ‘review videos’ that generate income from such links.

[ChrisBParticipant @chrisb35596]

Oh, it goes too far in my opinion, I made sure the posted video did not advertise anything apart from giving us a good discussion point, but saying that the youtuber has other videos where he reviews certain products…

Well, it's ok I guess…sigh!

[Neil WyattModerator @neilwyatt]

We are learning too… it's not always easy to decide what is and isn't OK.

Neil

[ChrisBParticipant @chrisb35596]

Neil, I read the thread posted a couple of months ago regarding the new COC relating to adverts from non contributing retailers etc. and I agree with the principle, however, not wanting to sound rude, I think this is taking it too far.

It's true you have to cut a line somewhere and it might be difficult to decide where to cut the line, however I honestly believe there was no harm done to any of our sponsors with the linked videos.

Just saying, removing the links creates some confusion to the thread as well – you get replies from posters which don't know what I'm talking about as they cant see the video, so the answers you get will be off course.

[EmgeeParticipant @emgee]

It'a a certainty the answers will be off course as the thread gets older, always happens.
But as you were referring to a video it does rather change the tone for those who haven't seen the said video.

Emgee

[norman valentineParticipant @normanvalentine78682]

I am sure that many of the people arguing against this have not done much aluminium casting. Once you have a furnace it is quick and easy. As a raw material I usually use car wheels which are a good quality source,

Inclusions? In over ten years of casting I have never had a problem. I never degass, but a few tiny bubbles in the casting do not matter, I would not use it for a critical part in my car.

But what a saving in cost and time! If I want to make a part that requires a large chunk of aluminium I can be machining it the same day for just the cost of the gas. I scrounge the wheels.

[ChrisBParticipant @chrisb35596]

Would you use a car engine cylinder head Norman and how much time you reckon it takes to melt say a kg of alu?

I'm very much tempted by the idea, aluminium suppliers are few, costs are high and you dont get much choice here. I mostly order the material I need off uk sellers (not linking any ) but shipping is a killer.

Have all the material to build a 2kw electric heat treat oven, it should be good for up to 1000°C so it could melt aluminium in theory. At 0.16€ per kwh it could work out as good solution.

[An OtherParticipant @another21905]

I've done lots of home ali casting, usually on the 'lost foam' principle using hard insulating foam (open cell packing foam is useless). The casting part is relatively easy, if you take care – (don't wear sandals ). I was advised to heat until it was thoroughly molten, scrape off as much dross as possible, then leave it to stand for a few moments before pouring to allow air to rise and disperse. This has worked well for me, and I have cast many bits and pieces, for example for a sanding disk machine, and for electric motor mounts. I have experimented with sand casting, but found it virtually impossible to get the various additives needed, despite many self-proclaimed experts telling me to use cat litter and so on.

As well as parts, I also cast slugs of ali to use for turning – usually OK, but do expect to find some blowholes sometimes, or very small pin-holes in the metal. There are many 'folk-lore' stories of what can be used as flux to help prevent this – most never seem to work, so the best way is to try it yourself. If it doesn't work, you can always remelt the ali and try again.

I used all sorts of stuff as raw material – cans are useless, they will burn to dross. Try old car engine bits, such as cylinder heads or pistons. My scrapyard lets me have them just for the scrap-metal weight.

Biggest 'don't' is don't spill the hot metal – it spits like hell on earth or cement – work on a sandbed is best.

There are many websites providing info, such as furnace builds and burners – mine is a stainless steel bread bin lined with a mix of fire-cement and some clay I found – works fine. The burner is home made according to J Reils ideas, and works equally well on Propane or (more slowly) on Butane (Propane is hard to get where I live).

[Michael Cox 1Participant @michaelcox1]

I have been melting aluminium and casting for a few years. It is relatively easy to make a propane gas fired furnace to melt aluminium from simple readily available materials. Old aluminium castings are the best source of material but I frequently mix old aluminium extrusions into a melt and this does not seem to be too detrimental. I usually make lost foam castings and these can have complex shapes. For stock for machining I usually cast in old tin cans for the larger diameters (50 mm -75 mm). The can after casting is simply cut and peeled off the solidified aluminium when cold. Smaller diameters are just cast in green sand using a bar of the right diameter as the pattern. The cast material usually machines very well. I once cast a rod from melted drinks cans but this was very gummy and it did not machine well.

To get a good clean casting without inclusions or void it is important to use a flux. I use a product called LoSalt which ios mixture of sodium and potassium chlorides as flux. This is readily available in supermarkets as it intended for people that need low salt diets. I desert spoonful of this in a one litre melt of aluminium brings all the dross up to the surface where it can be readily scraped of usinf a spoon.

I wrote an article that was published in MEW some years ago describing making the furnace and burner and describing some of the casting techniques. There is also some information on my website covering this, see:

**LINK**

[Author]

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