flexible tubing for steam

I wish to connect a steam generating boiler (60psi) to a small loco chassis for testing purposes. I suspect that the traditional method is to use copper tubing with a coil incorporated to give flexibility. If I used copper tubing it would need to be 5/32"/4mm OD. Is there any other type of tubing that would give more flexibilityand less heat loss than a copper tube arrangement? I am thinking maybe nylon tubing but I am a bit unsure about the stability of the connections (olive/union nut) when heated.

Mick

Came across this website which may be useful.

**LINK**

I have used small bore plastics/nylons up to 30 bar with olive/compression fittings in days gone by.

"I have used small bore plastics/nylons up to 30 bar with olive/compression fittings in days gone by" at 140 degrees C?

Even the best nylons (HTN range from DuPont) start melting at 264 deg C. Normal nylons will melt much lower temp than that. If your steam is high pressure or superheated it can easily reach over 200 deg C.

Silicone rubber hose with stainless steel woven outer casing would be far safer, rated at 500 deg C plus. Personally I would use copper, maybe wrapped with rock wool or fibreglass insulation. Much cheaper and easier to get, and easier to work with.

Steam @ 60psi will be at least 150 deg. C. AFAIK this is considerably above the recommended max. for nylon air lines.

Silicone rubber tube would stand the heat OK.

If your worry is heat-loss, fitting a plastic tube as a jacket over a copper tube would help.

Clive.

Snap with above post !!!

Edited By Clive Brown 1 on 14/09/2017 18:26:53

Blackgates do a grey neoprene tube that is suitable for steam, smallest is 3mm ID x 4.5mm OD

I've used ordinary 5mm O/D silicone fuel tube for steam up to 30PSI.

I think coffee machines use larger tube at higher pressures with a spring around it.

Neil

Edited By Neil Wyatt on 14/09/2017 18:46:22

Articles in ME some time ago about articualted locos suggested PTFE lined hydraulic hose, but I think you'll struggle to get it that small

Thanks very much gents. Looks as if it will be copper covered in silicon tube for now as I have it handy but neoprene and that stainless braided silicon look to be worthy alternatives as and when I get hold of some. (One of the problems in asking questions on this forum is that you end up like the kid in the sweet shop surrounded by goodies but not sure what to go for).

Mick

Ask a question of a dozen engineers, and you'll get a dozen different answers, eleven of them will get the right result in the end, a couple will be straight to the point, or you might just do it your way after all.

Ian S C

Goodridge braided brake hose **LINK**

Nick.