Can silicon tubing be used to conduct live steam ?

[brian777999]

Can this silicon tubing be used to conduct live steam from a boiler to a stationary steam engine ? I am thinking of using it on a temporary basis for testing purposes. The working temperature is from minus 60 to 180 degrees celsius :

 

http://www.ebay.com.au/itm/200702413425?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

 

 

 

[Edge]

Steam can reach much higher temperatures than 180 degrees under the right circumstances. I'm no expert on live steam models, but my personal view is that it would be best to stick its the traditional materials and technique, and I'm not sure if silicon tubing is one of them. I'd always err on the side of safety with live steam, it can go badly wrong.

 

Please bear in mind that I could be wrong though, others are undoubtedly more qualified than I am

Edited February 14, 2014 by Edge

[TheQ]

I would say no the listing states it is for Vacuum use, that is is resistant to collapse, it does NOT state it is resistant to expansion it probably can take the  temperature, as silicon tubing is used for cooking trays, and reinforced silicon tubing is used on Turbo Chargers.

The Q

[MarkC]

I agree. If anything were to go wrong, any personal injury insurance cover you may have is likely to be void. Far better to stick to conventional materials when dealing with steam, or indeed anything under pressure.

[PatB]

For a small engine with a small boler at low pressure (say <30 psi) with no superheater, it'll be fine. This table shows us that at 30 psi boiler pressure (3 bar absolute) the steam will be at 133^oC, leaving plenty of margin below the max working temperature. It may be slightly softened at 133^oC but not, I would expect, to the extent that it won't hold the fairly modest pressure involved.

 

If it did burst, so what? Based on your previous posts, it'll be a diddy little boiler operating a lowish pressure. All that will happen is that it will sit there venting steam in exactly the same manner as the safety valve can when asked to do its job.

 

Finally, I've noticed that unreinforced silicone tubing seems to be becoming quite a normal means of feeding lowish pressure steam engines, especially on small garratt or fairlie type locos where some movement between boiler and engine is inevitable. It's certainly not anything new or experimental.

Edited February 14, 2014 by PatB

[PhilH]

From a site which sells the stuff:

 

SILCON silicone tubing may be low pressure steam sterilized in-line or autoclaved at up to 250°F in a normal autoclaving cycle. However, if exposed to repeated steam sterilization or long-term high temperature or pressure, silicone will eventually relax and become gummy. It should then be replaced.

 

That obviously is for their brand SILCON.

Edited February 14, 2014 by PhilH

[Rabs]

Well, that's them trying to be confusing with their brand name!  Silicon is a hard, brittle semiconductor (computer chips and all that).  Silicone is a polymer which is based around a silicon chain (most polymers - aka 'plastics' - have a carbon based chain).  Loosely speaking: silicon is to silicone what graphite (or diamond) is to polythene and other plastics.  So to call a silicone polymer 'SILICON" is very misleading!

 

Silicones vary widely, some can tolerate up to 300C+ and some will fall over at about 100C.  If it were me I'd give it a go, but I'd definitely take precautions when running it, particularly for the first time (face shield, overalls, etc.)

[APOLLO]

Be extremely careful with live steam. It not only has temperature and pressure, but also lots of latent heat stored energy. It harms maims and kills when it goes wrong, and this includes models.

 

AS to using silicone tubing I cannot comment. As others say, research, source, and use piping, fittings and joints fit for purpose.

 

Brit15

[Titan]

What you need is the stuff used for model aircraft fuel lines - I think its neoprene? Good for up to around 50 psi with just a push fit over the pipes.
 
This has done a fair few miles using it for the flexible bogie connections at around the above pressure:

 

 

[PatB]

Does everyone wear protective clothing or go in fear of their lives and limbs in case their safety valve lifts? I repeat, provided that the boiler costruction is sound, particularly around the steam outlet nipple, if the silicone steam pipe fails, the very worst that can happen is that the breach will vent steam at the same rate as the safety valve must be capable of doing and should be expected to do occasionally.

 

No, you wouldn't want to be in the way when even a small safety valve goes pop, and neither would you particularly want to be too close in the direct path of a ruptured steam pipe, but it might anyway be generally considered a bad idea to put, for instance, your face right next to the sort of hot, spitting, fizzing monster that is a small live steamer.

 

I've had some professional involvement with pressure vessels that make a Big Boy boiler look like something from Mamod so I'm well aware of the potential of steam and other compressed fluids but what is appropriate caution in one case can be massive overkill in another.

[Titan]

You don't need to be paranoid about safety, for any small scale live steamer I have found that a bucket of water with a good sized rag or tea towel in it - and making sure it is always easily accessible, will cope with just about anything. Of course prevention is better than cure, but even though I am careful I still managed to set a meths bottle, loco fuel tank, and my hand on fire at an exhibition once. But because I had my bucket of water and wet rag at my feet I was able to deal with it so quickly that not only did I only manage to only slightly injure my hand (it was a little sore but no blistering or medical attention required as it was on fire for under 1/2 a second before being submerged in the cold water at my feet) I managed to keep my composure sufficiently to continue talking which meant that the people watching did not even notice, probably helped by the fairly invisible nature of the flames. I think they just thought that I was giving the loco a little polish with the wet rag draped over it, and maybe picking something off the floor whilst my hand was in the bucket, before continuing as if nothing had happened...

 

I also have a fire extinguisher handy as a last resort but it is very unlikely anything would ever get so bad as to need it.

[Paul G]

Yes DJB whistle comes supplied with some for attaching to the repacement bango fitting to the whistle. Never had problems with the tube it's self but conections made with little tie wraps can come off under pressure if not made tight enough. One has to handel live steam with some respect and care but the presure in a little SM32 boiler isn't that high. A pair of suitable driving gloves can be a good idea anyway if like me you drive manual not RC.