Hydraulic tubing; nylon or copper?

[Stuarth44]

Originally Posted by Christian Van H

Stuarth is right. Brake lines are 90% metal, and steering is mechanically linked. No comparisons. Dont forget that this is an instance where giving advice can get you both into trouble. Does anyone on this thread know the line pressures or even the helms this gentleman is using? Did it ever occur to you that this question might best be answered by the helm manufacturer? No steering in the middle of a crossing is serious stuff...

BTW, I WAS going to run my entire propane feed to the stove in hose lead thru a conduit...is hose bad for this too? DOH!

conduit is a good idea, I run all my underfloor John Guest water lines through a conduit, to stop fretting
i dunnu what your regs are, But ANYWHERE you can not get to or is permanent, please run in metal

[boden36]

Annealed copper is fine, easy to bend with a bending spring, easily available and cheap. We used standard half inch domestic copper tube available from any plumbing supplier. Just make sure that it is clean inside before installation. Hydrive is a good supplier of hydraulic steering components. Regards, Richard.

[mikereed100]

Originally Posted by Christian Van H

Does anyone on this thread know the line pressures or even the helms this gentleman is using? Did it ever occur to you that this question might best be answered by the helm manufacturer?

Don't know the line pressures but the helm pump is a Vetus, likely an HTP20. Rams are Vetus MTC72's. Vetus catalog specifies 6x10mm nylon or 8x10mm copper but they don't mention whether nylon can be used for long runs. Info is a little tough to get from the manufacturer. You have to ask questions through the distributor who then passes queries to the manufacturer. No answers as yet but I keep trying. So far I've learned more from the good folks here!

Mike

[mikereed100]

Originally Posted by Rick

There is a caveat with the use of this hose in that it must be fastened (easily done with standard nylon clamps screwed to convenient places) along its length so that when pressure is applied it does not quiver or attempt to straighten like a fire hose. That is the phenomenon that creates the "squish" feel when the hose is not held in place.

Good point. That's something I had not considered. As my installation includes runs through conduit and a stringer I may have to go with copper for that reason alone. I had assumed that it was distension of the nylon tubing that caused the "squish".

Problem is that due to lots of bends before entering the conduit, copper would have to be bent, then shoved and pulled through the conduit/stringer, hoping that it straightens as it goes... doable I suppose, though the profanity required may put my soul at risk.

Mike

[mikereed100]

I managed to find a Vetus hydralic steering manual online and it provided some interesting information. They recommend 6x10mm nylon or 8x10mm (3/8") copper. They do not make any distinction between the 2 as far as which is optimal and allow runs of up to 134' with the 20cc/revolution pump I have (allowable runs are less with higher volume pumps).

While researching copper tubing I found that 1/2" has a working pressure rating of 630 psi while 3/8" is 860 psi at 150F. The operating pressure of my system is 797psi. I assume this is why they recommend only 3/8" tubing.

Mike