online source for 3/8 Copper Pipe for hydraulic steering

[pukeanddie]

I'm adding an autohelm and I'm having a really difficult time sourcing the right 3/8 copper tubing for my hydraulic steering system. I can find soft 3/8 copper tube at the Home Depot, but I'm pretty sure that's not adequate. I've found copper tubing available online, but I'm not sure if it's the proper type. Is there something specific in the description I should be looking for?

Better yet, can anyone recommend an online source? I've tried some of the major marine suppliers, but can only find metric sizes available.

 

[Heron]

Most systems use flexible Hydraulic hose. I know mine does...between the bridge, Autopilot pump, Main helm and rudder Cylinder. Any Hydraulics shop could likely build some to your specs..

 

[jleonard]

McMaster Carr online. Type K is for high pressure. Will take more than your steering system puts out.
They have specs and you can figure out what you really need.

 

[psneeld]

I am going to hydraulic hose with reusable fittings....copper had its day....and still some uses....but why struggle with copper and bending unless ONLY cost is the issue.

 

[pukeanddie]

Thanks, I may consider flex hydraulic hose. I was mostly going with copper because that is what is currently installed and also what is described in the manual for my auto helm pump. The distance from my helm pump to the expansion tank is a long difficult run, and I'm sure that's much easier to make with hose.

Anyway, if I do go with copper I'm looking for type K. I can easily find that, but its usually only specified as water use, but I'm assuming that's ok.

 

[Heron]

Thanks, I may consider flex hydraulic hose. I was mostly going with copper because that is what is currently installed and also what is described in the manual for my auto helm pump. The distance from my helm pump to the expansion tank is a long difficult run, and I'm sure that's much easier to make with hose.

Flexible Hydraulic hose would seem to be a no-brainer considering your installation situation..

 

[pukeanddie]

If my existing system uses 3/8 copper, do I simply swap out for 3/8 hydraulic hose or does the flexible hose need to be larger/smaller diameter?

In terms of fittings, I'm assuming something like this is used?

 

[jleonard]

You want the same (or close) ID (Inside Diameter).
I also used 3 fairly short lengths of hydraulic hose when I installed my autopilot. I bought standard lengths from McMaster-Carr.
(2 at 24 inch, 1 at 18 inch)
I also added 3 "mini ball valves" (also via M-C) at the Ts just in case I ever need to replace the pump.

 

[FF]

When you spec the hose be sure to require swivel fittings on BOTH ends.

Saves turning a 20 ft length of hose to tighten it .

The reusable ends can be installed with a couple of wrenches , so some spair hose is a good idea for cruising.

Over sized copper tubing should be saved for the fresh water system , as it wont grow green gropsch like plastic tubing.

 

[twistedtree]

I've always understood that steering system manufacturers specify the use of copper pipe for a reason. It doesn't expand under pressure, or at least it expands much less than hoses. The installation instructions that I've read for anything larger than an outboard all call for copper pipe for this reason, and for minimal use of hoses only where absolutely necessary. Apparently your steering will get squishier and squishier the more hose you use, so it needs to be kept to a minimum.

Personally, I wouldn't want to risk building up a system with hose only to find it's squishy, so I'd go with copper like the manufacturers recommend. I can never remember the letter grading on pipe, but if K is the heavy stuff, then that's the stuff to use. Or better yet, check the installation manual to see what it calls for. Under no circumstances would I buy it at Home Depot. It will be the lowest grade, and lowest quality possible. But any plumbing supply house will either have it in stock or be able to get it. And at teh same time you will be supporting a local business instead of Junk-from-China, Inc. Then you just need a flaring tool and you are good to go. Oh, and try to use gas-rated flare nuts. They are much beefier and less prone to cracking.

 

[psneeld]

Steering pressures just aren't that high...certainly way less than normal hydraulics where losses would be unacceptable for other reasons.


Teleflex has been using mid pressure plastic /nylon tubing for awhile and Teleflex steering also has a variety of suitable hoses.


Copper is old school and common in boats where price for parts had to match low wages involved for all that bending plus the ancient hose issues.... whether some still specify it or not...

Not that copper isn't suitable...it's just not the only material suitable.

Now I am talking most small boat steering....if you have something for a much larger vessel or for a special application, different story.

 

[twistedtree]

Not that copper isn't suitable...it's just not the only material suitable.

Now I am talking most small boat steering....if you have something for a much larger vessel or for a special application, different story.

I guess it comes down to how small is small. I don't doubt that newer hose material will stretch less than older material. And no matter how much something does stretch, the longer your runs, the more cumulative stretch you will get. At what point does it become unacceptable? Who knows. My whaler has plastic tube (nylon, actually I think) for the steering and it works fine. My Grand Banks and Nordhavn both have/had copper tubing for all but the ram and AP pump connections. Were those boats both just built old-school, or does the use of copper really make a difference in a 47 foot or larger boat? I don't know.

What I know for sure is that if I were going to pull new piping through a boat, I would only want to do it once. I agree that running copper would be a HUGE PITA. I'm lazy, so tubing would be REALLY attractive, but I'd need to be convinced for certain that it would be acceptable (what ever that means). The engineer in me would probably be reading spec sheets on the nylon tubing material looking for expansion rates at different pressures and comparing that to copper tubing.

 

[pukeanddie]

In my case, does the fact that I woukd only be using the hose for a vent line to the helm pump mitigate most of the expansion cincerns?

 

[N4712]

I've ran heavy equipment a good part of my life and I disagree with the claim that it expands. I've never seen seen a hose expand in my life, if they did it was not visible to the naked eye and needed to be measured with a caliber. Just my experience. Once our copper gives the ghost up we're replacing it with quality hose.

 

[ulysses]

I too have run heavy equipment for years and seen both hyd. hose and copper tubing on the equipment usually the bends are made of K-copper and hoses on straighter runs. The more important thing is the securing of either material to insure vibration and chaffing is kept to a minimum.

dan

 

[N4712]

I too have run heavy equipment for years and seen both hyd. hose and copper tubing on the equipment usually the bends are made of K-copper and hoses on straighter runs. The more important thing is the securing of either material to insure vibration and chaffing is kept to a minimum.

dan

Yep, when my copper bites the dust the hose replacing it will be in the typical sleeve of canvas material. The only place ive personally seen cooper tubing is in pneumatic lines on drag lines and cranes. But that was older tech, now its all hydro. I do however see a lot of what looks to be steel piping.

 

[jleonard]

The hydraulic hose will not expand to a degree that it will affect anything. I believe the pressure is around 500 psi and that's low for hyd hose. Plus there is not all that much resistance on a trawler rudder and even if you need to displace a few more drops of oil to move the rudder you won't notice.
Go with the hose and don't look back.
Just make sure you chafe guard it where appropriate.