Page 1 of 2 12 LastLast
Results 1 to 25 of 29

Thread: Bending oval stainless tubing into spiral: how???

  1. #1
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Bending oval stainless tubing into spiral: how???

    As the title suggests, I'm wondering how I can bend oval stainless tubing into a tight spiral, here's a pic of a similar tubing, and the general design of the railing I'm making, the oval stainless tubing will be the cap rail, and be continuous from the top all the way to the bottom of the flights or stairs, there's 4 flights,

    The sketch shows the general layout of the railing, although the actual style will be different.

    Any ideas?

    Heat and bend? It's a pretty tight radius,, kerf cut and weld (and weld and weld and weld) and grind down?? I could achieve a tighter raduis by kerf cutting and welding but it mgith appear slightly segmented,

    I don't think I can heat up and twist that tubing tight enough without serious distortion and it losing its shape.


    Oh here's an idea, what about filling it with sand, then heating it up, and forming it, would the sand stop the tubing from distorting?


    Ornwoudl the sand melt inside when the stainless got to around 2000 degrees lol



    Sent from my moto g power using Tapatalk

  2. #2
    Join Date
    Sep 2015
    Location
    SE Pa
    Posts
    1,895
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Name:  F9FCFBB6-02E5-4DAE-BBBD-924633EC028C.jpg
Views: 568
Size:  80.7 KBName:  E61F4DE6-95CD-43E3-9FCE-9784B0EB352B.jpg
Views: 567
Size:  97.2 KB

  3. Likes DavidR8, tapwelder liked this post
  4. #3
    Join Date
    Nov 2005
    Location
    Nashville, TN
    Posts
    3,961
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Chicago Roll is an option, also. The likely can produce a single piece, at least long pieces and the pitch.

    Seems like a lot of work if you keep it in shop.
    Last edited by tapwelder; 11-16-2020 at 07:47 PM.

  5. #4
    Join Date
    Jun 2018
    Location
    Florida
    Posts
    1,051
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    The sand doesn't work but I have stuffed aluminum pipe or round rod inside of stainless tube to keep them from distorting and that works. The contract benders are pretty expensive unless your doing a large quantity, maybe RB Wagner.
    ***********************

    CR

  6. #5
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    The other option would be to use solid bar, and grind the edges and hope it matches? That seems like a lot of work.

    There's only 3 bends

    Approximately 20" each

    Sent from my moto g power using Tapatalk

  7. #6
    Join Date
    Nov 2005
    Location
    Nashville, TN
    Posts
    3,961
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I found Chicago roll to be reasonable, your profile might influence price. If it were mild steel it would be easier in many aspects.

    Perhaps bends sections are available .

  8. #7
    Join Date
    Sep 2005
    Location
    Cave Creek AZ
    Posts
    3,040
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I would try it with the sand. Wouldn’t need to be 2000 degrees, 800-900 would do it I would think. If it proves to be a problem, consider cutting the bends out of two pieces of flatbar and welding with a spacer, or just out of flat plate and hand finishing the edges. You might be able to roll a pice and use it for the turns, or stack two pieces and bend it in a square tube die. Just throwing out ideas, hopefully one will sound promising.

  9. #8
    Join Date
    Nov 2005
    Location
    Nashville, TN
    Posts
    3,961
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Perhaps, you could burn plate and weld tubing. Just seems like a lot of cleanup?

    Or burn the solid and bevel edges.

  10. #9
    Join Date
    Mar 2018
    Location
    Clovis California
    Posts
    2,223
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I have only known of companies filling with sand then bending.

    Since I was not in that line work I never try bending with sand. But seen large pipe and rectangle tubing bent using sand fill.

    Dave

    Quote Originally Posted by MetalMan23 View Post
    As the title suggests, I'm wondering how I can bend oval stainless tubing into a tight spiral, here's a pic of a similar tubing, and the general design of the railing I'm making, the oval stainless tubing will be the cap rail, and be continuous from the top all the way to the bottom of the flights or stairs, there's 4 flights,

    The sketch shows the general layout of the railing, although the actual style will be different.

    Any ideas?

    Heat and bend? It's a pretty tight radius,, kerf cut and weld (and weld and weld and weld) and grind down?? I could achieve a tighter raduis by kerf cutting and welding but it mgith appear slightly segmented,

    I don't think I can heat up and twist that tubing tight enough without serious distortion and it losing its shape.


    Oh here's an idea, what about filling it with sand, then heating it up, and forming it, would the sand stop the tubing from distorting?


    Ornwoudl the sand melt inside when the stainless got to around 2000 degrees lol



    Sent from my moto g power using Tapatalk

  11. #10
    Join Date
    Mar 2018
    Location
    Clovis California
    Posts
    2,223
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    FYI heat the inside radius. The out side will get very thin with heat.

    Dave

    Quote Originally Posted by MetalMan23 View Post
    As the title suggests, I'm wondering how I can bend oval stainless tubing into a tight spiral, here's a pic of a similar tubing, and the general design of the railing I'm making, the oval stainless tubing will be the cap rail, and be continuous from the top all the way to the bottom of the flights or stairs, there's 4 flights,

    The sketch shows the general layout of the railing, although the actual style will be different.

    Any ideas?

    Heat and bend? It's a pretty tight radius,, kerf cut and weld (and weld and weld and weld) and grind down?? I could achieve a tighter raduis by kerf cutting and welding but it mgith appear slightly segmented,

    I don't think I can heat up and twist that tubing tight enough without serious distortion and it losing its shape.


    Oh here's an idea, what about filling it with sand, then heating it up, and forming it, would the sand stop the tubing from distorting?


    Ornwoudl the sand melt inside when the stainless got to around 2000 degrees lol



    Sent from my moto g power using Tapatalk

  12. #11
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Does anybody have experience trying to bend tubing shaped like this with heat?

    Sent from my moto g power using Tapatalk

  13. #12
    Join Date
    Oct 2014
    Posts
    3,012
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I think you'd need some dies the same as if it was square tubing. Filling with sand may work but the sand has to completely dry and then packed tightly in the tube and the ends capped so the sand stays put.

  14. #13
    Join Date
    Sep 2014
    Posts
    1,412
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Quote Originally Posted by MetalMan23 View Post
    As the title suggests, I'm wondering how I can bend oval stainless tubing into a tight spiral, here's a pic of a similar tubing, and the general design of the railing I'm making, the oval stainless tubing will be the cap rail, and be continuous from the top all the way to the bottom of the flights or stairs, there's 4 flights,

    The sketch shows the general layout of the railing, although the actual style will be different.


    Any ideas?

    Heat and bend? It's a pretty tight radius,, kerf cut and weld (and weld and weld and weld) and grind down?? I could achieve a tighter raduis by kerf cutting and welding but it mgith appear slightly segmented,

    I don't think I can heat up and twist that tubing tight enough without serious distortion and it losing its shape.


    Oh here's an idea, what about filling it with sand, then heating it up, and forming it, would the sand stop the tubing from distorting?


    Ornwoudl the sand melt inside when the stainless got to around 2000 degrees lol



    Sent from my moto g power using Tapatalk

    You have to cold work it, or yellow hot work it, there is no in-between.

    If you filled it with a solid aluminum bar as was mentioned that would keep it pretty nice. And then just put it through the Hosfeld or whatever you are going to try to bend it with. I used to make Teflon dies to bend aluminum and brass handrails sideways. I would just grab a scrap block of aluminum hollow it out on the table saw and put in a Teflon liner. I almost cut off a finger doing something like that on the Hosfeld, with two guys working on it simultaneously I was the holder, haha.

    If you distort stainless steel while it is red hot it will develop visible stress cracks, especially if you use any hammer type forming. You can warm it so it is not 50 degrees, but you cannot turn it red and work it. I would probably go with a solid stainless steel flat bar it is cheap, get a couple twelve footers and just bend them and form them and just round the edges with a carborundum wheel or even 24 grit sanding discs on the right angle grinder. Then I would use a high-speed angle grinder with 3" roloc discs 40 grit to smooth out the 24 grit marks, and then 80 to remove the 40 grit marks. You need bee's wax or don't bother it makes the discs cut through stainless like it is wood. You want the metal hot so the wax melts. Then you have so many options. It depends on the finish you want. You could sand with orbital or vibrating sanders, but it is a slow and tedious thing. They make some wheels now that are supposed to do a good job on lightly scratched material, and then you need polishing wheels and rouge, which you need no matter what you are doing if it is a mirror finish. If it is brushed it is easy you just sand it by hand in the direction of the grain and you are done sanding then I just go with the grain with a nylon pad by hand that takes off any hooks the sandpaper creates. I usually use 220 grit for the brush look. On large flat pieces, I use an autobody planer sander to make brush marks.

    Sincerely,

    William McCormick
    If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.

  15. Likes ronsii liked this post
  16. #14
    Join Date
    Mar 2018
    Location
    Clovis California
    Posts
    2,223
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I wish had any experience

    I have only did round pipe using heating on inside bend. It was repair work too and you can get away with more.
    Most my experience was making straight again.

    Note they do this type bending in Hobbies

    Dave

    Quote Originally Posted by MetalMan23 View Post
    Does anybody have experience trying to bend tubing shaped like this with heat?

    Sent from my moto g power using Tapatalk

  17. #15
    Join Date
    Jun 2018
    Location
    Florida
    Posts
    1,051
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Once again sand does not work, it will distort right along with the tube. And this shape will try to go round when you bend it so you will need some type of dies to keep the profile.
    ***********************

    CR

  18. Likes Oldendum, ronsii liked this post
  19. #16
    Join Date
    Nov 2005
    Location
    Nashville, TN
    Posts
    3,961
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Low temp melting metals might work as a filler? Somebody gave me some bismuth alloy it melted at sub 200 degrees. I think it expands as it cools, I recall it breaking a beaker. If it works in would be reusable.

    I have made dies of delrin. Pretty easy to turn.

  20. #17
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I could fill it with aluminum , that melts at around 1200

    Sent from my moto g power using Tapatalk

  21. #18
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Or maybe cold forming then annealing cold forming then annealing and repeat until it's formed?

    Sent from my moto g power using Tapatalk

  22. #19
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Called sharpe, they said they don't have any dies at all for that shape, no surprise

    He suggested doing the solid bar,

    Sent from my moto g power using Tapatalk

  23. #20
    Join Date
    Mar 2018
    Location
    Clovis California
    Posts
    2,223
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I would make my own dies and use my own press.

    Dave

    Quote Originally Posted by MetalMan23 View Post
    Called sharpe, they said they don't have any dies at all for that shape, no surprise

    He suggested doing the solid bar,

    Sent from my moto g power using Tapatalk

  24. #21
    Join Date
    Jun 2008
    Location
    Hardwood Lands, Nova Scotia, Canada
    Posts
    1,854
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Maybe two pieces of round tubing or pipe the correct diameter to give you the radius and flat bar joining them?................Mike

  25. #22
    Join Date
    Apr 2013
    Location
    Marina del Rey
    Posts
    715
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    Quote Originally Posted by mrmikey View Post
    Maybe two pieces of round tubing or pipe the correct diameter to give you the radius and flat bar joining them?................Mike
    I think you're onto the right approach. The curved section could be fabricated from two tubes, then fixtured and sheeted together.

  26. #23
    Join Date
    Apr 2006
    Location
    Sydney Australia
    Posts
    1,159
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I'm thinking I would get to rolled in solid , without shaping it , them grind and linish to shape .
    I think its too tight a radius to get a good result with that wall thickness.
    It will increase the chances of the roller having a die , but in solid you will probably have to send it away.
    Labour intensive but probably less than adding a tube to the side . Possibly a better finish .
    Last edited by Brett; 11-17-2020 at 08:27 PM.
    A good guess is better than a bad measurement

  27. #24
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I found some half round bar from Mcmaster Carr, also online metals has it, I'm gonna get some 1.5" solid bar and weld this half round on each side, will make the same profile, I may end up doing it for the straight sections too, just because of logistical issues in trying to get the oval tubing in time.

    Sent from my moto g power using Tapatalk

  28. Likes ronsii liked this post
  29. #25
    Join Date
    Jun 2012
    Location
    Ct
    Posts
    2,407
    Post Thanks / Like

    Re: Bending oval stainless tubing into spiral: how???

    I'm thinking of heating the flatbar in the forge, twisting/bending it into the proper shape, I rolled this plate to the required radius, and then heating the half round and welding it on as I go, matching the core of the solid bar, it'll probably take a fusion weld, minimal filler rod, then just smooth it out with the sanding pad.

    Sent from my moto g power using Tapatalk

  30. Likes ronsii liked this post

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Page generated in 1,610,867,557.53008 seconds with 13 queries