Model steam - boiler needs a dose of ?

  Diemmess 18:40 04 Oct 2009

I more enjoy making things that using them.
My 5” gauge Super Simplex had its steam test and only track drive in 1999.

After that since it was so much effort to take it to a club track I mothballed it.
Drained everything, applied oil, WD40 etc. kept it in its box indoors.

Last month with none of my nine grandchildren interested, and with heavy heart decided to sell it.
In the magic way that word gets around I met my opposite, a man who would rather spend his time in an active club running an engine, rather than build one.

The hydraulic and steam test certificates have long since expired and I now will be glad to wave it bye-bye because everyone can see it is safe and it steams well but won't hold the hydraulic test pressure

Little by little I have dealt with small seepages all over the place and it still won’t hold the hydraulic pressure of 160psi.

There’s nothing to see. The culprit is one or both clack valves at the backhead of the boiler connected with the emergency hand pump. Undoing the union having pumped it up to pressure, shows a steady drip which obviously slows as the pressure falls.

The nearest friendly Guru now has the opinion that over time, thin films of copper oxide black scale are producing tiny flakes which upset the seating of a ball in a clack valve. He recommends a hose to flush the boiler out.

Alright to say flush it out, but it is no milk bottle needing a rinse!
The thing is very heavy with small access apertures.
There is another Guru in another club whose word I trust, but I respect his weekend and will delay asking him ‘til next week

The boiler is copper with bronze fittings silver soldered throughout
Does it make sense to use a proprietary central heating cleaner or washing soda (sodium carbonate)?
Anyone with experience of this sort of thing?

  Forum Editor 18:55 04 Oct 2009

is compatible with all the metals you mention, and others.

It will remove pretty well everything in terms of scale,sludge, etc., but it won't dissolve solid particles in suspension - you will have to flush thoroughly to do that.

  morddwyd 20:49 04 Oct 2009

As a matter of side interest, long ago I received advice never to use WD40 for long term applications to ferrous material since it contains sufficient water to be corrosive.

  Deekio 21:26 04 Oct 2009

If you have built a 5" Super Simplex you are obviously a model engineer of some accomplishment.
I have myself built steam engines they are fascinating, I also had nine grandchildren who did,t care,So try my solution! And it worked.
Build a single cylinder steamie, but then you've probably already got an oldie that you built
when you started. \\\\\\\rig it up to a light
system that shows up outside your workshop,
Saying Grandads left home! Flickering of course.

  wiz-king 05:48 05 Oct 2009

When I was working in a garage a customer thought he would clean out his cars cooling system by putting WUL in it, it took us days to flush it all out!
I have just had a new boiler and as part of that the system was power-flushed with a cleaner, the amount of muck it shifted was amazing, just make sure you neutralise the boiler afterwards.

  Picklefactory 11:08 05 Oct 2009

I'm afraid I know nothing about steam engines, but we use a fair amount of hydraulic valves, a colleague of mine (Hydraulics specialist) has mentioned in the past that a trick of the trade on ball sealed valves, is to give the ball a errm percussion adjustment (Tap with a hammer), to generate a perfect seat. I have no clue as to whether your ball joint is accessible for that.
Not exactly a precise engineering solution, but apparently quite a common fix that works.

I must say, I didn't think a clack valve had a ball though, I thought it was a type of hinged lid sort of affair, but I'm far from sure of that.

  Diemmess 22:34 05 Oct 2009

A very good response thank you all.
I don't now think it will come to a need for a special wash out, in fact it has been filled and emptied several times with no sign of discolouration or sediments when draining.

Guru 2, after a friendly conversation offered symapthy!
He too suggested the unmentionable wallop, which I had already tried.

I have spent a huge amount of time reviving half forgotten skills, remaking two other screw down valves each having a tiny seep and a very rough action.

The dodgy ball non-return valve is the least accessible and its removal means draining the whole thing again.

I'll get there in the end but as Guru 2 said "Mr Sod's about."

  WhiteTruckMan 00:04 06 Oct 2009

This might seem like a daft question but you dont happen to live in a hard water area by any chance?

(I think you might see what this could be leading up to...)


  Diemmess 09:07 06 Oct 2009

Judged in terms of how much scum when using toilet soap, this is a relatively soft water area.
Certainly not hard water when compared with my boyhood in Wellington Shropshire.

  Picklefactory 09:22 06 Oct 2009

Is there a spring behind the ball? If so, can you increase the tension with some washers to increase sealing pressure? If the spring tension has weakened over time, maybe that might help.

  Diemmess 17:52 06 Oct 2009

No springs and things, these check valves are supposted to slam shut with a stainless ball 3/32" in diameter pressing against a too small hole which is supposed to be truly round and razor edged.
Main work today has been two needle valves which are OK at low pressure but seep at 160psi. One no longer does, the other will require more attention tomorrow!

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