White metal – its availability & uses ?

[clivelParticipant @clivel]

[clivelParticipant @clivel]

While paging through some of my ME back issues last night I came across an article in the Oct 2007 issue entitled "Basic casting in white metal"

This looks to be a relatively pain free way of metal casting, but what was not clear, is what white metal is, where one gets it, and more importantly what uses it may have in a model engineering context.

[JasonBModerator @jasonb]

Tiranti's sell various grades and all the other items you will likely need, also gives a brief explanation of what it is.

 

Its a bit soft for most of our uses but I suppose if you want to hold something without marking it may have a use as a jaw lining or could be machined into a nesting holder for machined work. Not to forget the bearing grade which is often refered to a babbit.

 

J

Edited By JasonB on 29/02/2012 20:10:59

Edited By JasonB on 29/02/2012 20:13:26

[david newman 9Participant @davidnewman9]

I made a feed nut from white metal for a milling machine some 35 years ago no sign of wear after all this time, and it has been well used.

[BazyleParticipant @bazyle]

The bearing metal material has very specific amounts of antimony and copper in with the lead and tin to give it the wear resistant properties. Related to printers' type metal. It is quite amazing that they managed to find the formula with the technology of 400 years ago. Ordinary white metal starts with around equal parts lead and tin so is a form of solder but probably with more unknown 'crud' but it has a low melting point like solder and is therefore easy to cast. Very high levels of tin make it Pewter as in tankards.

It may be that there is a lot of bearing grade around so it gets used for general casting but if you just get the solder version it will be a really crap bearing.

In model engineering bronze is more likely to be used for a bearing but white metal is commonly used for casting axle box/spring assemblies for G1 down to smaller gauges. I'd say G1 is counted as a model engineering rather than a model railway size.

When looking for white metal don' t be fooled by aluminium now used for eg car door handles and carburettas or cast zinc that used to be used for these things and Dinky toys. Zinc will bubble in vinegar, aluminium in caustic soda, pewter won't react with either but white metal might depending on its impurities but not as readily.

[David LittlewoodParticipant @davidlittlewood51847]

The unusual property of antimony is that (like water) it expands on freezing. Its use in type metal, AIUI, is largely because of this property, which makes the finished letter much crisper; most metals shrink on freezing and the edges tend to round and blur a little. I think the copper may be for increased wear resistance. For all I know the antimony may help this as well, but I doubt it would be the additive of choice for this purpose as it is rather toxic.

David

[Billy MillsParticipant @billymills]

I do a bit of spin casting of tin alloys in silicone rubber moulds using a centricast machine. As Jason has said, Tiranti's is a good starting point . There are many different alloys for different uses, For a ME low temp casting can be very useful for making small quantities of identical parts such as nameplates, bezels, cases and lineside models of all kinds. One route is to make an original in brass or plastic then make a two part silicone rubber mould then cast directly into the mould.

You can do most moulding tricks e.g. use nylon rods to make cast in holes, install bushes into the mould to be cast in and join complex parts by soldering. Imagination is the major limit. You don't have to use silicone rubber moulds or centrifical casting, simple jobs can be cast into alloy moulds, cuttlefish or whatever else that will withstand 300 degrees C for a few seconds but it is vital to be certain that the mould is completly dry before pouring the metal in.

Finally I would point out that most "Pewter" is tin, copper and antimony , it has been in use for thousands of years as drinking vessels and plates without mass extinction.

Billy.

[Sub MandrelParticipant @submandrel]

I've heard that a good source of white metal is diecast model cars, matchbox/corgi sort of thing. You may get a load from a bootsale, but beware some of the older ones are worth £££!

For low stressed parts the metal is quite good – better than Mazak!

Neil

[georgegreekParticipant @georgegreek]

As David Littlewood has alreadt mentioned, *type* netal is perhaps the only metal that I know of whihc can be cast and create an exact copy without a press or other equipment (centrifugal e.t.c.).

If old *letters* can not be found, similar metal cab be bought from sources selling matl to bullet loaders called hard (25% Antimony and 75% Lead) at $ 2.5 to 3 . pound.

One can make a mould from dentist;s plaster and reproduce parts from a plastic original (or your creation if artistic enough).

Regarding the poison thing, well, both metals can be poisonus under conditions, but I am 70 and was making my own tin *lead* sokdiers since 10. I suggest you mekt the metal in open space and avoid inhaling aby fumes (invisible). Be carefull but not hysteric about it.

Further information can be given f wanted.

George

[clivelParticipant @clivel]

Thanks all, some really useful information , much appreciated

[Ian S CParticipant @iansc]

There's a photo in my album of a traction engine I assembled for a friend, I think the kit was by Fine Cast, or some similar name, it's white metal. To go with it I carved a little man in a boiler suit, and made a wheelbarrow, and a bucket. Ian S C

[Clive HartlandParticipant @clivehartland94829]

Antimony is put into the mix to make it harder, in fact with heat treatment the hardness can be increased.

Clive

[Samuel Brown 2Participant @samuelbrown2]

I am thinking that whitemetal may be useful for model tracion engine parts. Steering wheels, brake wheels etc.

[JasonBModerator @jasonb]

It will be too weak, best to fabricate with steel spokes and steel or stainles steel rim.

J

[Chris TriceParticipant @christrice43267]

Posted by Stub Mandrel on 01/03/2012 20:15:08:

I've heard that a good source of white metal is diecast model cars, matchbox/corgi sort of thing. You may get a load from a bootsale, but beware some of the older ones are worth £££!

For low stressed parts the metal is quite good – better than Mazak!

Neil

Er.. I think Dinky cars are made of mazak (sometimes called zamak) and cast in rigid moulds. Whitemetal is softer and heavier and has a lower melting point. A lot of model railway kits are centrifugally cast white metal either in vulcanised rubber or silicon rubber moulds. It's base constituents are closely related to tin/lead solder. It can also be simply poured in to an open rubber mould although centrifugal casting tends to have less of a bubble problem. Dusting the moulds in talc first helps.

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by David Littlewood on 29/02/2012 22:54:48:

The unusual property of antimony is that (like water) it expands on freezing. Its use in type metal, AIUI, is largely because of this property, which makes the finished letter much crisper; most metals shrink on freezing and the edges tend to round and blur a little. I think the copper may be for increased wear resistance. For all I know the antimony may help this as well, but I doubt it would be the additive of choice for this purpose as it is rather toxic.

David

David,

Antimony does shrink slightly on freezing (liquid density 6.5, room temp solid density 6.7). As you say, it does modify the type metal alloy so that it shrinks very little on casting. Bismuth is one of the few metals that does expand on freezing (liquid density 10, room temp solid density 9.8). Plutonium also expands on freezing (not very useful for the home workshop though).

cheers,

Rod

Edited By Roderick Jenkins on 28/12/2012 19:09:33

[SpringbokParticipant @springbok]

We used white metal in bearings in the 60s Citroen cars used them extensivly in there engines for bearings, I still have a set of scrapers somewhere in my workshop

Bob

[JasonBModerator @jasonb]

Good write up of some "babbitt" being poured on a model engine on HMEM

J

Edited By JasonB on 28/12/2012 19:49:13

[Chris TriceParticipant @christrice43267]

Most internal combustion engines have white metal big end and main crankshaft bearings. Many classic and vintage cars have white metal bearings that aren’t made anymore but it’s quite feasible to have the old ones re-metalled.

[Charlie,Participant @charlie18171]

Used to work for Corgi Toys in Northamton, The metal used in the diecasting of the model cars was called Mazak, Low melt and rejects could be remelted and used again over and over,

[Ian S CParticipant @iansc]

Remetaling bearings in cars was a routine job for the motor mechanic of yesteryear. Our HR 6 Ruston Hornsby has just had its big end remetaled in the last month or so. Ian S C

[Nigel BennettParticipant @nigelbennett69913]

On the subject of Mazak, if there's any significant lead in the alloy it becomes very unstable with time – the dreaded "Mazak Disease" which has reduced many valuable die-cast models to piles of crumbly dust!

Going back to the OP, I have some white-metal castings on my 9F – they were supplied by one of "our" usual suppliers for the axle-box covers on the tender to reproduce the very fine raised lettering. (They were hopelessly the wrong diameter, but I have managed to let them into a brass surround to bring them up to size.)

White metal as a working component (as opposed to a decorative item) would be pretty hopeless as it simply isn't strong enough. (Think of joke centre-punches and spanners!) It can, as others have noted, be used as bearing material for axle boxes, eccentric sheaves and the like by pouring in the molten metal on to a tinned/fluxed surface – casting in situ – and them machining to finished size, just like in full size.

[TerrydParticipant @terryd72465]

Posted by Stub Mandrel on 01/03/2012 20:15:08:

I've heard that a good source of white metal is diecast model cars, matchbox/corgi sort of thing. You may get a load from a bootsale, but beware some of the older ones are worth £££!

For low stressed parts the metal is quite good – better than Mazak!

Neil

Hi Neil,

Mazak as used in diecast toys is not really suitable for home casting, in terms of modelling and ease of casting low temperature white metals can be used which melt at less than 200ºC, However mazak as used in die cast toys melts at around 390ºC and needs comparatively high pressures into metal dies to achieve fine detail. White metal casting is possible at home with simple equipment and is the basis of many small 'cottage industries' such as scale figures for model railways and 'Wargames'.

My previous neighbour used to make quite exquisite military figures which sold for comparatively large sums using white metal, silicone rubber moulds and a centrifugal casting machine in his garden shed. A standard soldering iron will easily melt such models without care, however he was able to solder fine detail using a 100 Watt soldering iron and low temperature solder. "Only a matter of practice" he would say as he blithely soldered a scabbard to a 1/35th scale Prussian officer – his sword was removable and the roundels of his tiny spurs rotated – the Prussian's that is, not my neighbour's .

Regards

Terry

[Sub MandrelParticipant @submandrel]

I played Advanced Dungeons and Dragons in my mispent youth. These days it's apparently Warhammer 2000 – "Dwarves in Space".

All good fun and I have some nice figures. I imagine your friend was around in the days when Ral Partha were the bee's knees in figures.

I have always been in awe of the finest military figure modellers. I once (like 35 years ago) made a conversion of an Airfix Hussar to 'Pocket Hercules' a short fellow in (IIRC) the Crimea (guided by an articale in MM). He and his steed were mounted on the wooden plinth of the desklamp never completed in 3rd year ICT or whatever it was called then. My dad still has it in a glass fronted cupboard. Making reins and straps from plastic card! Give me a good chunk of CI any day!

Neil

[Ian S CParticipant @iansc]

Got a nephew whos into war gaming, Warhammer, hes got thousands of dollars worth of army, men and vehicls, some in resin, proberbly half is white metal. He's busy packing it all up as he has to move out of his house so that earthquake damage can be repaired over the next month or so, he'll proberbly live in a motel while the work gets done. Ian S C

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