Is Brass suitable

[David GParticipant @davidg]

[David GParticipant @davidg]

Not strictly a model engineering question but…..

I have an instant hot water dispenser in my kitchen and the plastic water dispensing nozzle liner has disintegrated. unsurprisingly a replacement part on its own is not available.

I can easily turn up a replacement nozzle out of some brass bar that I have but was wondering whether it would be suitable. The water goes through the nozzle at about 80-90 degrees, I can turn it out of a single piece so there will be no soldering.

As this is used to make tea and coffee I want be sure I'm not going to end growing and extra limb, etc .

Thanks

Dave

[wheeltapperParticipant @wheeltapper]

Can't you get hold of a piece of nylon rod?

Sounds safer to me.

Roy

[Terry LaneParticipant @terrylane]

I'd use the brass – thousands of water heaters are crammed full of brass fittings.

[Russell EberhardtParticipant @russelleberhardt48058]

I have a coffee machine in which I have replaced a plastic nozzle with brass and I'm still here – but then when I was young we had lead pipes and they were considered safe.

Russell.

[Brian Dickinson 2Participant @briandickinson2]

Brass will be fine. In time you may get de-zinkification but thats a long way down the road.

Bri

[Sub MandrelParticipant @submandrel]

As most taps are made of brass, I'm sure you'll be OK.

Neil

[Ady1Participant @ady1]

Brass might become a health issue once you reach 175 years of age

[Martin WParticipant @martinw]

The bodies of compression fittings and stop cocks etc are all made of brass and approved by water authorities, WRAS approvals, so it's used regularly on potable water supplies and as such shouldn't be a problem. Only thought is do you know what kind of brass you have as some contain lead but even so I don't think you'll come to any harm . I've like many others have been using leaded solder since I was a kid and the exposure there is far higher than anything that will leach out of the brass.

Cheers

Martin

[Terry LaneParticipant @terrylane]

Posted by Ady1 on 29/03/2012 00:18:43:

Brass might become a health issue once you reach 175 years of age

Ya think?????? Now you've got me worried!

[Martin WParticipant @martinw]

Tel

I will PM you in about 101 years and let you know whether there were any problems in using these materials .

Martin

[BazyleParticipant @bazyle]

In 175 years someone might ask " The brass nozzle on my Ascot (powered on biogas) has finally corroded away. I have found a bit of 20th century material called plastic for only £25,000, is it safe to use?" Answer " Are you mad? That plasitc stuff is full of horrible chemicals that was in only used for about 50 years before the plastic mines ran dry".

[Clive HartlandParticipant @clivehartland94829]

Solve the problem, use a bit of stainless steel.

Clive

[geechrParticipant @geechr]

I work in the plumbing trade and we use quite a lot of brass in water fittings. There will be no health risks in using brass in the application you describe. I would not recommend Nylon unless it is grade specifically formulated to work in domestic water systems.

Regards

Chris Gee

[David GParticipant @davidg]

thanks for all the feed back. Brass it is then.

Dave

[simon cochranParticipant @simoncochran85684]

You say it is an instant hot water dispencer, if so be careful as it may be you are causing a problem by replacing a plastic componant with a metal one.

Basically if the water is heated in certain types of "instant" heaters, the water contained is live, and so including a metal part where a plastic part is required may just render yourself or your loved ones liable to shake hands with the national grid.

Simon

[Keith Wardill 1Participant @keithwardill1]

I find it very hard to believe that instant water heaters can result in 'live' water – how does this work then? It would be interesting to see the internals of such a heater described. If this is so, then even the original fitting (plastic?) would not reduce the lethal capabilties of such a machine – or do you work for the Health and Safety Alarm and Despondancy Department.

[Martin WParticipant @martinw]

Live Water?? This sounds more like an urban myth than actuality. Distilled water is an insulator but the stuff that we get delivered in our homes by the various water companies is certainly NOT pure in any sense of the word. It contains various additives plus natural salts so that it behaves as an electrolyte i.e. It is conductive. In fact if you take time to measure it you will find that tap water exhibits a resistance of a few tens of K ohms with the probes about a couple of inches apart.

If you have a domestic water heater that delivers LIVE WATER then I suggest you put it in the skip before it kills you!!

Cheers

Martin

[Ian S CParticipant @iansc]

There is a type of water heater that can cause the "live" water situation, it's illeagal, it can be got round by indirectly heating the water, but even then I don't think its allowed. There are 2 electrodes with a gap, there needs to be a certain amount of impurities in the water for it to work (not distilled). You could try the method (take care)just stick two bare wires in some water, one to phase, and the other to neutral, KEEP your fingers out of the way, switch on the power. This system will only work on an AC current. This experiment is dangerous, don't let the kids do it,(thats when I found out about it). Ian S C  ps  some early electric jugs used this system.

Edited By Ian S C on 02/04/2012 12:04:55

[geechrParticipant @geechr]

It is quite possible and safe and legal to have a "bare wire" or "wire in water" heating elements working at 240V. Dolphin electric showers made over 10 years ago used bare wire heating elements. So do Zip water heaters sold in the UK. Most German intantaneous electric water heaters also use this technolgy.

The products are safe because the design makes sure the electrical current, flowing from the bare wire heater to earth, is so low that it is safe. The electrical conductivity of the water coupled with the volume of water between two strategically placed earth contacts at the inlet and outlet water pipes is used to control the current.

The plastic outlet of the water heatwer will be downstream of the exit earth and so be safe to replace with brass.

[Steve WithnellParticipant @stevewithnell34426]

It's amazing how a "can I swap a plastic bit for a brass bit" question can produce such a huge amount of collateral learning!

[Keith Wardill 1Participant @keithwardill1]

As almost everyone has noted, if this system was ever used, it was 'old' or 'early' designs – ask yourself why it is not still in use?

Never saw one of these heaters in 35 years residence in Germany, and fitted several 'instantaneous' heaters myself in rented apartments in Germany – of course, this is no evidence that they do not exist.

Very strange statement from geechr – The products are safe because the design makes sure the electrical current, flowing from the bare wire heater to earth, is so low that it is safe. The whole point of any 'safe' system is that current is kept to a 'safe' level – the problem is, how do you ensure that? – a simple wire becomes lethal if it carries too much current (overheats, insulation melts, etc, etc) – so how do you guarantee that the current is kept low under all conditions – including potential faults? Surely no-one deliberately designs things so it is not safe (on second thoughts….) Seems like a good reason to me for not using this system.

As for 'strategically placed earth contacts….' – presumably both at the same potential, so no current flow?

Some interesting design possibilities though……

[John BaguleyParticipant @johnbaguley78655]

Many of the instantaneous water heaters on the market today use 'bare wire' technology where the water passes over a bare wire element. They heat the water much quicker than an insulated element. Just Google for 'bare wire instantaneous water heaters' and you'll find loads of them for sale in the UK.

John

Edited By John Baguley on 02/04/2012 20:43:59

[Martin WParticipant @martinw]

As they say. "Well I'll be bu****ed ". They must be isolating the mains voltage from the water somehow, possibly some fancy switched mode system, otherwise losing an earth would potentially, no pun intended, make the system live to mains voltage. Ah well I think I will wear rubber boots in the hotel showers in future however shocking it may appear , pun intended.

Cheers and thanks for the heads up on this.

Martin

[Sub MandrelParticipant @submandrel]

I had a bare wire immersion heater – at least it ended up that way and boy did it boil the water right into the header tank (galvanisd, thank goodness).

I replaced it with an inconel clad one.

Neil

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