Bending stainless tube

[prv]

Already thinking of modifications to the new boat, and we don't technically own her for another month

Going to make a minor extension to the pushpit to hold some gear. I've found Seascrew's excellent range of fittings (don't think my welding is up to the job!) but will need a couple of 120-degree-ish bends which I want to do on site to get the "ish" just right.

I've bent a certain amount of 15mm copper tube with a spring before. Obviously 25mm stainless is both bigger and harder, but is it still feasible? The radius is not critical, and can be fairly large. I can see I might end up standing on it between blocks rather than pulling it round my knee. If not, any other ideas? I'm not going to buy a bending machine for one job.

Cheers,

Pete

 

[VicS]

I'm not going to buy a bending machine for one job.

But you might regret not hiring or borrowing one

 

[saltylegs]

one option that worked for me a couple of times with a largeish radius was to fill the tube with damp sand in place of a bending spring.
good luck

 

[dancrane]

Hiring looks possible: http://www.jewson.co.uk/en/template...=cat540066&pageType=Category&itemId=cat540068

What's the new boat? Still a gaffer?

 

[uxb]

A bit OT but have at look at Cooney Marine web site and check out the video of their funky pipe bender.

 

[Chris_robb_ndota]

The last one I hired was only about 20 quid for the day and made the bending a doddle, I would recommend doing the same

 

[wotayottie]

Either fill the tube with sand or fill it with water and then freeze it. Neither will be easy. My inclination would be to do a mock up in copper which can be done using a spring and then take the result to a stainless tube fab place where they have pipe benders.

 

[earlybird]

Bending even 1" SS tube is utterly different from copper. I presume it will be about 1/16" wall thickness.
For any sort of proper job, you will need an hydraulic bender and formers for a 120 deg. bend, unless it's the most gentle of radius.
Doing it with muscle power and body weight is completely impractical, unless you compete in World's Strongest Man.
Best left to the professionals IMHO.

 

[ghostlymoron]

Recommend a pipe bender with a scaffold tube over the handle. The one from Jewsons says it's for thin walled stainless.

 

[Robert Wilson]

Either fill the tube with sand or fill it with water and then freeze it. Neither will be easy. My inclination would be to do a mock up in copper which can be done using a spring and then take the result to a stainless tube fab place where they have pipe benders.

+1
I was quoted over £100 for supply and bend for a new rail for my spray canopy. On top of that was the charge for three small welds, to take hinges etc. Decided not practical or affordable, for now.
Finding someone to actually bend it was very difficult, even in Inverness.
Good luck.

 

[rob2]

I discussed making some bent (offset) stanchions with a fabricator in our owners' association. He said that the normal grade of tube used would require a hydraulic bender and even then would probably need to be taken to cherry red to achieve it! That also means that it will require re-polishing after it has been shaped. I've tried using the hand benders on copper pipe and obviously don't have the technique - the tube always kinks! I'd second the option of making a template on site in copper and having it bent by a fabricator who has all the equipment and the skills to use it.

Sorry to be so negative, I'd love to be shown I'm wrong!

Rob.

 

[Lakesailor]

I put some bends in my SS tiller. Very gentle bends.
I went to the local steel fabricator who let me use his hydraulic bender. He suggested I do several small bends, moving the pipe a bit each time. It seems SS tube kinks very easily.
Even with the proper gear it was difficult.

(Rubbish picture from video)

 

[BERT T]

Bending stainless pipe

Unless you have the proper gear (and I don't mean a plumbers pipe bender) DON'T even think about trying it. You will end up destroying the stainless pipe and having to go and buy another piece. and

 

[christhefish]

bending stainless tube 25mm you will need a conduit bender with a top former I have bent 100s of meters using this method

 

[ytd]

I bent some 18mm od pipe with a hardwood form and hydraulic jack. Very large radius bend. Tried the same thing with 25mm pipe and it kinked. The 25mm pipe seemed to made of a much harder ss.

 

[dancrane]

(Rubbish picture from video)

Pardon my doubt...and blame the picture-quality if I'm way off course...but to me, your tiller looks more like aluminium.

 

[Searush]

Believe me, Lakey will know the difference . . .

Any tube will kink without something inside to support it like densely packed sand or a plumbers spring. If using a spring, over bend & then relax it or you'll never get the spring out.

I bent my pulpit by allowing it to hook over a shackle while the tide went out & the 7 tons of SR hung off it.

It put 2 kinks in it & tore it out of the fore deck. It is now with a specialist metal fabricator (the Iron Works near Caernarfon) to be straightened. He reckons heat will allow it to relax back to its former shape (approximately) with a little encouragement. The outcome remains to be seen.

I am anticipating a bill of around 50 squid for around 1-2 hours work. at those sort of prices I would get it fabricated - if you really must get it done. But I always like to sail a boat for a season or two to be sure that my ideas for modifications are really necessary.

 

[Robert Wilson]

But I always like to sail a boat for a season or two to be sure that my ideas for modifications are really necessary.

I find this is the best policy for nearly all projects in life. I haven't time to be busy!
SWMO does not appreciate this form of project-management..............

 

[dancrane]

Believe me, Lakey will know the difference . . .

...But I always like to sail a boat for a season or two to be sure that my ideas for modifications are really necessary.

Sound advice. Not having a boat at all for a few years, is the reason why I'm so full of "wouldn't this be good" 5hit.

Apologies to Lakey, I'm sure his metal-recognition buries mine.

One angle we haven't really touched on: how much heat must stainless reach, before it's pliable enough not to kink? Does it permanently lose its shiny surface, or could we all be out there, blow-torching bends into our pushpits? (Those of us with boats... )

Edit: I've just realised, inflexible piping will probably kink even more easily when it's flapping about at 1200ºc like so much wet cardboard. How the heck do they make tight curves in the stuff when it's new?

 

[Swinranger]

I believe that 25mm stainless tube can be bent around a former if the radius is not too severe, haven't tried it myself though!
When I made my stern arch, I used a Hilmore EL25 conduit bender which worked very well, but did need a "cheater bar" on the handle to bend the 1.6mm wall tube.
Think I paid about £300 quid for it on eBay, but consider it a good long term investment.
Might be a second hand one out there for less?