Casting brass

[PlasmaParticipant @plasma]

Hi all,

Back on the door knobs again! Some of the fittings at Wentworth are very ornate and obviously not machinable.

What are your thoughts on small scale brass founding at home?

What kind of gear is required and is it within the scope of home workshop practice?

Just pondering if setting up to make these things is possible. There is a brass foundry near me but I'm not sure of the requirements to have small runs of work done.

Best regards Mick

[PlasmaParticipant @plasma]

What’s involved

[Brian OldfordParticipant @brianoldford70365]

A risk associated with the casting of brass is the possibility of over-heating the melt and evaporating the zinc content. Even as a semi-retired pattern-maker it took me quite some time to find a non-ferrous foundry that would take on small volumes. Please feel free to PM me.

Brian

[Rik ShawParticipant @rikshaw]

Tried it years ago. Unless you are going to make a regular thing of it I would say its not worth your while. By the time you have made your mold boxes and patterns, acquired your special casting sand, purchased a suitable crucible and tongs, sorted out the gas kit for the melt etc. etc. you'll get the idea.

Mind you, it seems these days that some folk use a 3D printer for the pattern and adopt a sort of lost wax process – you'd still have a melt to do though!

Rik (trying to be helpful)

[John HinkleyParticipant @johnhinkley26699]

Have you tried this person, who advertises on the Home Workshop site? I've not used them myself but they appear to provide the sort of service you are asking for. Got to be worth an email, at least, I'd have thought.

Abbey Casting

John

[AdrianRParticipant @adrianr18614]

I dont know what they are like but I came across them in a back issue of MEW the other day. Fenland Castings

[V8EngParticipant @v8eng]

Apparently this Foundry featured on “We are Middlesbrough” seems like they might like work, may be worth an enquiry.

Foundry

[Brian OldfordParticipant @brianoldford70365]

One small word of caution should you choose to go down the lost-wax (investment) route is the phenomena of "double-contraction".

Not only will the final brass casting contract within the mould after reaching solidus the wax model before will also shrink as it freezes within the rubber mould taken as a "squeeze" off any original.

Edited By Brian Oldford on 22/05/2019 07:48:25

[Neil WyattModerator @neilwyatt]

Small lost-wax is reasonably easy, as brass is nice and fluid so yo just need a reasonable 'head' to ensure the mould is full and avoid 'sinks' – except for the problem of zinc burning off. Not only does it affect the alloy it brings the risk of 'fume fever' which has influenza-like symptoms.

Basically red hot molten brass will easily 'take fire' giving off white smoke.

When casting small (about a cubic inch of molten metal) I've used borax as a cover-flux to stop the brass burning, while not 100% successful it helps a great deal.

Always melt brass outdoors though!

Neil

[Dave Smith 14Participant @davesmith14]

On small, 1 to 2 cm parts that have been lost wax cast for me by Shapeways, I find a 2% shrinkage allowance is sufficient.

Dave

[BazyleParticipant @bazyle]

There was a demo of brass casting at the Warwickshire show in 2016. Unfortunately I missed the demo but speaking to him later he made it sound quite easy, just a bit different from aluminium. If you can handle the colour difference then bronze is perhaps easier. Lots of modellers seem to do bronze.

Some other people might have seen the demo and perhaps the person who gave it is on the forum.

 

Edited By Bazyle on 22/05/2019 23:29:22

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