Bending Stainless Tube

[CliveG]

How easy is it to bend Stainless Steel tube?

I have to make a new pulpit and want to make an arch radar type to mount wind gen and various aerials.

Can it be bent with an electricians conduit bender?
I intend to use PICEA 316 fitting for joints but need to form the curve at the bow etc.

 

[boatbuilder]

You can buy preebent sections , this will prevent" waisting", which will occur if you use a conventional pipe bender.

 

[tabernacleman]

Hi, I did a grab handle type bar for the sprayhood by using a piece of 4" x "2 X 36" piece of timber with a hole drilled through near one end and by insereting the tube graduallly bent the tubing to shape, suprisingly effective with no kinks and all performed on the pontoon /forums/images/graemlins/wink.gif

 

[Avocet]

Depends how tight a radius you want. Stainless is a pretty horrible material to work. You might be able to do it by welding a plate over one end of the tube to block it off, then fill it with dry sand and make sure it's shaken down firmly. When it's full, weld a cap on the other end of the tube. The sand stops it kinking at the bend. Cut the caps off afterwards. From my own experience, it's pretty hard to make an arch or pulpit-type structure dymmetrical by this method!

 

[ianabc]

I have just completed bending 1 inch stainless steel pipe ( schedule 40) for the safety rails that were then weleded to 36 inch stantions. I cut matching u's in the top of the vertical pipes and the curved guardrails were dropped into the matching cutouts.

A professional at grat expense welded the assembly together plus the wind generator 2 inch pipe too.

Bending was accomplished using a borrowed pipe bender.

The machine was essentially a hydraulic jack attached to heavy plate with two pipe matching pieces inserted so that the hydraulic ram could push into the middle of a 2 foot section with the pipe held in the matching left and right pieces. I believe tha the special pipe shaped pieces could be replaced with a simple vertical bar.

All that would be necessary would be a aluminium plate 2 feet by 2 feet, two heavy bars to hold the pipe and a hydraulic jack pushing in the center. End cap of jack ram must match shape of pipe....

Overbending is always a problem as there is spring back in any bent piece.

Correcting overbends in easy.

Just find a telephone pole or any strong pole and fix one end behind an object, bend the other back.....


I used a plywood template to help match the desired curve.

 

[boatmike]

Yes you can use a conventional pipe bender if you have the exact size formers.

 

[oldsaltoz]

How easy is it to bend Stainless Steel tube?

I must admit I found it very easy sitting on balcony of the yacht club overlooking the boat and watching the professionals install our new cockpit canopy.

I will have a go at most things, but like to think I know my limits and am happy to pay for a well designed and very well finished job.

This was all polished finish ranging from 3 inch to one inch tubing and included brackets for bracing the targa and bait station, as well as solar panels on top with a fitted white canopy under them.

The only bending I did using stainless steel included the use of heavy springs inserted into the tube before bending, then spending time getting them out after the the bend was put in, also note I avoid welding whenever possible, and particularly on stainless tubing.

Very few DIY stainless steel tube projects will stand up to a close in spection, and it's difficult not to get close to them on boats.

I wish anyone attempting a good finish the very best of luck.

Avagoodweekend......

 

[sailorman]

Guapa recomends Mr Stainless @ Levington /forums/images/graemlins/grin.gif. Now THAT is recomendation if ever there woz one /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif

 

[FullCircle]

Clive, as an apprenticed tinbasher, I recommend employing someone to do the job. Hydraulic bending gear is required really.
Are you going to do your arch in 25mm? Bit weedy looking perhaps?

As Guapa says, Mr Stainless has a good reputation.
I have a contact who is also an excellent craftsman, but seems to work on a pre-Gregorian calendar, that is to say he is always 13.66 days behind, and has a lottery system using folded bits of paper and a biscuit tin to decide what job to do next.

 

[vyv_cox]

Shallow curves are quite easy to do manually, I just pushed the end of the tubing into a cradle and heaved up on it. Anything more than a few degrees is much more difficult. The old-fashioned method is to pack the tubing with sand to prevent it from collapsing, similar in principle to the plumber's spring. Personally I would have someone who has the necessary skills and equipment do the bends for me, particularly if they are more than about 15 degrees.

Incidentally, I find Picea 316 to be just about the most expensive supplier of fittings and definitely very pricy for tubing. Baseline were about the cheapest I found for fittings and they have a better range. I bought my tubing from an Ebay dealer, slightly more than half the price of Picea 316.

 

[Juggler7823]

I'm just about to start bending the tubes for a canopy frame, using 22mm SS tube. Baseline here my first choice but when trying to order was told that 3m lengths would cost at least £78+vat for transport or could collect (a near 500 mile journey!). The price at Picea was dearer but the transport cost was less. I bought from Pointnorth at Holyhead. The price was cheapest of all and transport only cost £7+Vat! Baseline have the best and widest selection of fittings including joints and hinges to extend the tube for longer lengths and ease of stowage etc.

I looked at the Baseline pipe bender, more than £613!! but it will give smooth and sharp bends without kinking. I borrowed a standard (plumbers?) pipe bender which was bought bought from Machine Mart for £110. This has a 12 ton press and formers from half to 2 inches. I do not require any sharp bends, just the opposite in fact. I do very slight bends at 2inch intervals along the pipe. The curves at the ends are sharper and it does leave very slight indentations on the inside of the bend but this is not really a problem. I've done some test bends and I am very satisfied with the result.

 

[CliveG]

Thanks to all for the advice.
I do have access to a pipe bender.
(I am in the Building Game)

I may take the bent pulpit to Mr Stainless and see what he can do with it.

As far as an arch is concerned I may go for this e-bay offering

 

[sailorman]

[As far as an arch is concerned I may go for this ]

Clive have you considered the extra weight on the stern, its supprising how heavy a s/s structure can be

 

[damo]

That's why I'm building an arch in 25mm tubing, angled and curved so it sweeps back but stays ahead of the backstay. Hopefully the design is stiff enough - I got some ideas from a US manufacturer's website. I desperately want it to look elegant in comparison to some of the no-doubt functional but ugly constructions I've seen.

I have problems with trimming the boat to keep weight out of the stern, but I want a radar/wind gennie/solar panel mount so I'm trying to keep the weight forward.

As per the OP's question - I have access to an engineer's hydraulic bending machine but I have managed not to use it yet because the recycled big mobo canopy frame I have acquired has bends in the right places!

....now welding stainless tubing is a whole other set of problems /forums/images/graemlins/grin.gif

 

[Mudplugger]

Clive,
Guy in Haven Rd. Colchester has a very sweet s/s bending m/c......charged me not a lot /forums/images/graemlins/smile.gif for bending up, transom arch, pushpit (both sides) and granny bars....very helpful and into boats as well! pm if need more details. HTH

 

[tabernacleman]

Hi PrinceMadoc - you should have tried the 3" x 2" before lashing out all that money on benders, where are you in Wales if you don't mind me asking. /forums/images/graemlins/ooo.gif

 

[Drascomber]

If the work piece is long enough, gentle curves can be done a little at a time using some kind of wooden fulcrum. Tighter curves need a hydraulic bender.

Very tight curves - well I have just had a quote from a tube bending company to put 180 degree bends with a 76mm centreline radius into 22mm 316 stainless tube. For two off they want £72 each! including £10 worth of material. For a qty of 20 it is cheaper at £24.50 each (All excl VAT & Dely).