Brass types

[Richard KParticipant @richardk16713]

Hi
I’ve tried a search but could somebody clarify for me the different types/grades of brass normally available and their uses.

The model I’m building (Minnie T.E.) plans / Book call for various types of brass:-
1/. Sheet suitable for annealing and bending (flanging).
2/. Hard brass sheet
3/. Hard brass flats / rounds (for Slide & regulator valves)
4/. In places it just says “Brass” (including for the sheet for Valve & Regulator chest covers – no PB covers supplied with the castings). All bushes are Phosphor bronze.

Suppliers web sites quote things like Compo brass, Half hard brass, Engraving brass, CZ2120, CZ108. CZ120, CZ121 which I’m sure is clear if you know the answer.

I have found suppliers generally unhelpful, in most cases not bothering to reply at all or with comments like “just use this it will be OK”.

I am aware of the problems of de zincification and don’t want to get it wrong. So what grades should I be looking for? 1-4

 

I’m not in the UK. so don’t have a club / friendly boiler inspector to ask.

Thanks in advance

[Richard KParticipant @richardk16713]

[Diane CarneyModerator @dianecarney30678]

Hi

You may have seen this already :Brass

 

If you look at the ‘knowledge base’ here you will find a lot of information but it does not necessarly translate into the terms you require. Worth a read all the same.

 

CZ120 is engraving grade brass and is ‘half hard’ – in other words it’s a bit easier to file. It has a lead content, about 3 percent or so.

 

CZ108 is not quite as soft and is also known as ‘common brass’ or ‘yellow brass’. It has no lead so a bit harder to work but is a good colour.

 

There are other ‘grades’ with names such as jewellers brass, cartridge brass, guilding metal etc. but they are all just variations in the proportions of copper to zinc giving different properties.

I would say that if otherwise unspecified, CZ108, common brass is what you need. You may also see it referred to as CuZn37 or ISO-C2720. It’s all the same stuff.

 

Here’s another good source of information: metal2models

 

Anyone else please feel free to correct me / add to this.

Diane (back street metallurgist ‘n-all)

Edited By Diane Carney on 25/11/2011 12:34:10

[JasonBModerator @jasonb]

1. Brass for tender CZ108

 

2.CZ120

 

3.CZ121

 

4. CZ120

 

All this brass will be above the water line so no worry about dezincification

 

I would avoid using 108 for machining as its quite soft and teh swarf is stringy so generally not nive to machine. The harder brasses will have swarf in the form of small chips and be a joy to work

 

J

Edited By JasonB on 25/11/2011 13:34:38

[Bob LambParticipant @boblamb44747]

Diane – thank you for the metal2models link – most interesting. Along the same lines I would really like to know the difference between various bronzes especially where to use the different grades – are there any pitfalls to look out for? Thanks again to Richard for asking the question I have meant to ask for some time! Bob

[maurice bennieParticipant @mauricebennie99556]

Hi everybody

When at work I used to have a brass look alike .It was possible to heat it and bend and form with a hammer .It was called DELTA metal ,I can not find any mention of it. Am I dreaming ?

Maurice B

[Chris TriceParticipant @christrice43267]

Try this:

 

http://www.smithmetal.com/metals/brass-alloys.htm

 

[Chris TriceParticipant @christrice43267]

CZ132 seems to be the one to use where dezincification could otherwise be a problem.

[maurice bennieParticipant @mauricebennie99556]

Thanks Chris , A useful site

Maurice .

[Robert DoddsParticipant @robertdodds43397]

Hi Richard,

You could do a lot worse than look at the publications of th Copper Development Assn

See their section on brass at

http://www.copperinfo.co.uk/alloys/brass/brasses-properties-and-applications.shtml#s7

 

Bob D

[Richard KParticipant @richardk16713]

Thanks everybody I’m a bit slow coming back – been otherwise engaged.

 

The posted links answered my question fully – especially from Chris – a very clear & concise page.

 

Diane ‘knowledge base’? I thought searching via the banner above did that – is there a specific page here for the ‘knowledge base’ if so I’ve not found it.

 

My Google search brought back just too much information

 

[TerrydParticipant @terryd72465]

Hi all,

 

As the subject of de-zincification has arisen I have always wondered if this is as real a problem as is sometimes suggested. Tubal Cain seems to have thought not and Mamod and Wilesco boilers have been of brass for many years without apparent problems.

 

Personally I have always used copper for boilers and will continue to do so, but am just interested as to why those manufacturers used brass and how they get away with it.

 

Best regars

 

Terry

[DavidinHKParticipant @davidinhk]

Brass is usually quite safe to use long term in freshwater systems without any risk of dezincification. Where brass does let itself down is in the presence of chlorides when life expectancy is short. This is why standard grade brass is used rarely in marine environments. On shore there is much less risk of attack by chlorides. Even in hardwater areas, carbonate based contamination does not have any significant effect. Using distilled water will eliminate any significant risk …. although I should add a caveat to that: Tests of retail “distilled water” have sometimes revealed the presence of surprising amounts of impurities. Real distilled water as used as feedwater in high pressure water tube boilers starts at under 1 ppm chloride content with actual water drum levels remaining under 25 ppm.

 

David in HK

 

 

[David LittlewoodParticipant @davidlittlewood51847]

Just be careful, as quite a lot of “distilled water” is actually de-ionised. Some de-ionisers (including virtually all those in domestic use) actually produce a very weak solution of sodium chloride, which will of course concentrate itself in the boiler. This also, obviously, can apply to the tap water in your house if you have a water softener. (You should have at least one tap not supplied via the softener, usually the kitchen tap, but then that will still have all the hardness-causing substances in it!)

 

David

Edited By David Littlewood on 01/12/2011 02:07:46

[DavidinHKParticipant @davidinhk]

Thanks David. That is a very good point.

 

Also to beware is that a lot of “distilled water” comes from reverse osmosis water makers. We used these for drinking water in the Navy and usually ran them at about 100 ppm chloride content output. This was very pleasant to taste, much nicer than the steam plant distilled water standard of less than 1 ppm at which we ran the evaporator output for steam ships (and also for auxiliary steam domestic systems on diesel and gas turbine ships).

 

For model boilers, the feedwater standard clearly does not need to be anywhere near so stringent as for steel boilers operating at up to 1200 psi and 700 deg C superheat. However, any chloride content is not so good for any pipe system with brass fittings and definitely not so good for brass shells of boilers.

[Gordon WParticipant @gordonw]

I was emptying the small dehumidifier last night and it struck me that this is distilled water, we get several litres a week. Is there any reason why this cannot be used in boilers? I have used it as battery water.

[DavidinHKParticipant @davidinhk]

As long as you don’t live in a bad acid rain area and haven’t had the windows open continuously, he condensate is probably as close as you can get to pure H2O

[Diane CarneyModerator @dianecarney30678]

Posted by Richard K on 30/11/2011 16:53:09:

 

Diane ‘knowledge base’? I thought searching via the banner above did that – is there a specific page here for the ‘knowledge base’ if so I’ve not found it.

Sorry Richard – I wasn’t very clear. By ‘here’ I meant on that link ‘Brass’ in my post, not the ME website.

Diane

[Richard KParticipant @richardk16713]

Diane thanks, I thought I was being dim and had missed something on the ME site.

 

@GordonW Yes I was wondering about that also, I’ve used the condensate from my dehumidifer in a vertical boiler thinking it must be reasonably pure & also calcium free. I’d never considered the PH possibilities, just assumed it would be neutral. Must get some litmus paper & test it.

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

If you are going to use dehumidifier water might i suggest you run it through a filter, a ground coffee one should work well and be easily available, because if your house is anything like mine carpet fibre and dust are a very noticeable addition.

chriStephens

[Brian Dickinson 2Participant @briandickinson2]

Have a look at this suppliers web site for specs http://www.manchestermetalsgroup.co.uk/

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