Zinc based alloy?

Good morning,

I'm in the process of making a Stirling Hot Air Engine. The construction requires a cast flywheel made from "zinc based alloy". Casting for me is out of the question, so I wondered if I might be able to get a billet of said, or similar, material, 90mm dia x 25mm thick. Mild steel is an option, with a bit more machining to bring the mass down, but I'd like to keep the finished engine as true to the plans as I can.

Thank you.

You could substitute Aluminium instead

‘Zinc based alloy’ would typically refer to MAZAK or ZAMAK which is used for mass-production die castings.

My guess therefore, is that the words may be an oblique reference to a commercial item.

MichaelG.

Standard zinc ingots are smaller than the size you want. Time to think again

Myfordboy on youtube uses ZL12 to cast his flywheels. Its casting temp is about 500C so is not so hard to do casting. Artisan Foundry sell 1KG ingots for £7.99. Maybe near you could cast you a blank.

I guess they suggest a zinc based alloy because it's a little heavier than Aluminium for a flywheel.

They clearly expect you to be able to cast the zinc based alloy, because there's a drawing for the required pattern.

That's why I am considering steel and reducing the mass.

Many old designs expected you to cast your own parts and I'm with Adrian that something like ZL12 would be ideal, think it is only 10% lighter than cast iron. Myfordboy does do one off castings for people so you could contact him for a casting or just a simple cast disc.

Steel would be OK and probably a lot less hassle.

"They clearly expect you to be able to cast the zinc based alloy, because there's a drawing for the required pattern."

Stuart turner show flywheels but they don't expect you to cast your own?

What engine are we referring to?

Regards Ian.

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Are you psychic ... or did I miss an important detail in the opening post ?

MichaelG.

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Edit : That was posted before I realised that you were the originator of this thread.

My question should therefore have read:

Do we need to be psychic ... or did I miss an important detail in the opening post ?

Edited By Michael Gilligan on 30/04/2020 10:30:55

Ian, you want to take a look at some of the old mags plenty have pattern details in them as I said, That 1936 midget engine I made a few months back had details of all the patterns and you were expecte dto cast your own, even some of Westbury's designs in ME expect you to make your own patterns.

Michael, you missed the words "construction requires a cast flywheel made from "zinc based alloy"

As the OP says he can't do the casting he wants to cut from solid in a similar material hency the search for a billet of same.

Edited By JasonB on 30/04/2020 10:21:15

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< with Pantomime voice > Oh no I didn’t !!

Those words include nothing about patterns, or home foundry work

a cast flywheel is a cast flywheel, whoever makes it.

MichaelG.

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Edit: ___ see edit of my previous post

I will shut up now ... it’s turning into a bad day.

Edited By Michael Gilligan on 30/04/2020 10:32:26

Easy to shoot posters down when you're looking at something no one else is. Give us ALL the information available if you want a reasonable answer.

Think the original question has been answered, if you don't like the answer, do your own thing.

And yes JasonB seen lots of drawings giving pattern details but these assume the person reading has the ability to be able to either cast the bits themselves OR has access to a local (not nowadays) foundry and didn't have access to t'internet.

Regards Ian.

Edited By Circlip on 30/04/2020 10:39:45

"Casting for me is out of the question" that suggests to me that the OP can't do home foundry work

The engine is one I made at secondary school around 1972. A school "Hot Air Engine" project by T. E. Haynes. However, it's been lost (I'm sure it's somewhere, we just can't find it). My Father was so proud of it, I want to make another for him now I've sourced the plans.

My school used to do alloy casting back in the 60's. Lots of cast garden hand forks full of gas bubbles.

Thanks for the suggestions, but please keep it civil.

Question: Is brass considered as a Zinc based alloy? Some are 50%, or more, Zinc.