Soldering Copper Pipe

[Stemar]

I have a sea water cooled Volvo 2003. There's a pipe between the thermostat and the manifold that has, in effect, a gap in the middle with tails for rubber pipe. At present, these are connected by a loop of rubber pipe that has a tendancy to kink, so I'm thinking of replacing it with a U of copper pipe and short staight rubber tails.

Is there any reason for not using ordinary domestic copper pre-soldered fittings for this?

 

[Phoenix of Hamble]

Nope....

I've done just the same in the past on cars.... works just fine..... and that has to be just as tough an environment as a boat...

 

[alastair]

Dont see why not. There is no special 'marine grade' copper. My only reservation is vibration. The original rubber design would be tolerant to this, the copper less so.
Good Luck

Alastair
www.javacharter.co.uk

 

[Stemar]

Thanks for that, it's rather what I thought. My only concern was introducing another dissimilar metal, or rather metals from the solder into the engine, and whether there'd be any issues with corrosion of the solder.

 

[Phoenix of Hamble]

No.... just make sure you wash it down properly before fitting, as this will remove any excess 'flux' from the joining process... the flux is quite corrosive....

 

[Blueboatman]

? Worth trying reinforced rubber pipe first from car parts outlet ? Or is the bend radius just too tight for that ?

 

[MedMan]

Do you know a handy plumber with pipe benders? It would be a few minutes job to bend a U and then you wouldn't have any joints or solder to worry about.

 

[howardclark]

Sorry but standard solder will not survive the vibration. You need to braze it. Use silver which will take the vibration. Some of mine have lasted 30 years!

 

[graham]

I have soldered copper pipe bits and pieces for marine engines successfully. Dont know if any will survive 30 years but I know some have lasted over 10 years and are still giving service.

Whatever you use try to avoid any high points which could become an airlock.

Providing both ends of the pipe are attatched to the engine and you dont use any brackets or clips attatched to a bulkhead or other part of the boat then the vibration is not such an issue.

I fully agree that silver soldering or brazing would be stronger but then it takes it away from being a DIY job.

i have just had another thought.Some of the pipe connections on small Volvos push a plain end of pipe into a simple O ring type seal.If you make it solid will you still be able to connect both ends back into the seals?

 

[Stemar]

Thanks all.

The existing pipe has right angle bends to tails for rubber pipes. I'll be joining my new bit with rubber pipe, so it'll be easily removable. For the same reason, I'm not too worried about vibration. I expect the rubber to be enough to damp any vibration and support the copper U - which is as small as I can make it.

 

[Russell]

The standard pipe goes straight from the thermostat to the manifold. I modded our one about 15 years ago by cutting a piece out and soldering on 2 standard 90° bends so that I could tap in for the calorifier. I also soldered a U shaped piece of copper across the back to hold it all together. I only used normal plumbing solder and haven't had any problems yet......
You could always get a standard pipe if you don't need the hot water, probably only 2 fortunes from Volvo

 

[savageseadog]

I'd be very cautious of the effects of vibration, if you do solder it make sure it's supported . I would suggest using a corrugated rubber hose for vehicle cooling systems, I noticed Halfords selling it and it's really handy looking for that kind of problem. It bends round a treat. I noticed it a few months ago and made a mental note.

 

[snowleopard]

The radiator I used on my kit car had a spigot larger than the ID of the hose. I soldered on a couple of standard plumber's reducers and it's been fine ever since. That was in 1992.

 

[Lakesailor]

A friend with a steam boat had a leak on a 10mm copper pipe to feed his boiler that was under boiler pressure. He said he would have to "hard solder" it to withstand the pressure (blow-off at 140 psi). I take it he meant silver solder. Other than that he has used Yorkshire fittings on low pressure (by boiler standards) pipes without problems. He's had the boat 30 years.

 

[andy_wilson]

Just fit a straight pipe between them... or a calorifier!

 

[Talbot]

difference between the copper plumbing , and boat hose is merely the pressure in the system. However, this could be enough to stress a normal silver solder joint. I would at least carry a spare , and if you can get it properly braised then that would be better. Strongly recommend that you clean the copper thoroughly and use some flux on the joint area to ensure a good join.

 

[capsco]

You could always use a compression fitting.

 

[Stemar]

[ QUOTE ]
You could always use a compression fitting.

[/ QUOTE ]I could, but the only ones I can get locally are brass. I expect it would take years to dezincify enough to matter, but I'd rather not find out!

 

[capsco]

In that case why not use a stainless steel fitting ??

 

[BarryH]

Why not just use a bending spring in the copper tube.You can bend copper by hand very easily. No soldered joints + no worries. Just a thought!