Home made cast Aluminium

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

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.

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

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.

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)

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 .

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.

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

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.

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 .

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

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.

Noel Shelley does demos at exhibitions and clubs.

Mike

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?

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.

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!

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

Neil

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.

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