i am doing some rail and pushpit work on my 23' hunter and need to bend some .069"x7/8" ss tubing. so far my local muffler shop says its too small dia for their bender and my local plumbing supply and machine shop say no also. any ideas who or how this stuff can be bent? tia~ william
how to bend 316 ss tubing?
- Thread starter william3045
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technique
one effective technique is to fill the tubing with sand then bend. the sand prevents the wall from buckling. there are tubing benders available for most diameters at hardware stores. the most obvious solution would be to find a shop that makes biminis.....they bend stainless all the time.
one effective technique is to fill the tubing with sand then bend. the sand prevents the wall from buckling. there are tubing benders available for most diameters at hardware stores. the most obvious solution would be to find a shop that makes biminis.....they bend stainless all the time.
Pipe Bending
I was hasty in posting - and take it all back. 1/2" Rigid Conduit (GRS) is probably a closer match (to 7/8" S/S) at 0.80" O.D. and 0.218" wall thickness. The stainless, though thinner, will be harder than mild steel conduit. Also - recalling my days (25-30 years ago) as an expert conduit bender - it wasn't really all that easy becoming proficient at GOOD bending. I THINK, that having had to ask, YOU PROBABLY WILL NOT BE ABLE TO BEND UP AN ATTRACTIVE & FUNCTIONAL PULPIT. See Robert Taylor's post. S/S tubing @ 7/8" O.D. (0.875") with 0.069" wall thickness is not exactly analogous to Electrical EMT Conduit (nearest size is 3/4" @ 0.922 O.D. & 0.049" thick), but close enough, if you are very careful to keep good pressure on the bender (foot pedal) with your foot when making the bend. The bend will not be even, and the accuracy may be off if the proper foot pressure is not applied. Bending isn't difficult, but getting the right amount of bend, in just the right location can be tricky - and requires some theory and practice. Some helpful references: The Basics of Bending Conduit (parts 1 & 2): http://www.ecmweb.com/mag/electric_basics_bending_conduit_2/ http://www.ecmweb.com/mag/electric_basics_bending_conduit/ Conduit Bending Theory: http://www.porcupinepress.com/_bending/TheoryAndDrawings.htm Gardner Bender (Bender product & instructions): http://www.gardnerbender.com/whats_new/products/fr_np_Bigben.html
I was hasty in posting - and take it all back. 1/2" Rigid Conduit (GRS) is probably a closer match (to 7/8" S/S) at 0.80" O.D. and 0.218" wall thickness. The stainless, though thinner, will be harder than mild steel conduit. Also - recalling my days (25-30 years ago) as an expert conduit bender - it wasn't really all that easy becoming proficient at GOOD bending. I THINK, that having had to ask, YOU PROBABLY WILL NOT BE ABLE TO BEND UP AN ATTRACTIVE & FUNCTIONAL PULPIT. See Robert Taylor's post. S/S tubing @ 7/8" O.D. (0.875") with 0.069" wall thickness is not exactly analogous to Electrical EMT Conduit (nearest size is 3/4" @ 0.922 O.D. & 0.049" thick), but close enough, if you are very careful to keep good pressure on the bender (foot pedal) with your foot when making the bend. The bend will not be even, and the accuracy may be off if the proper foot pressure is not applied. Bending isn't difficult, but getting the right amount of bend, in just the right location can be tricky - and requires some theory and practice. Some helpful references: The Basics of Bending Conduit (parts 1 & 2): http://www.ecmweb.com/mag/electric_basics_bending_conduit_2/ http://www.ecmweb.com/mag/electric_basics_bending_conduit/ Conduit Bending Theory: http://www.porcupinepress.com/_bending/TheoryAndDrawings.htm Gardner Bender (Bender product & instructions): http://www.gardnerbender.com/whats_new/products/fr_np_Bigben.html
bend has to be more of a curve
Thanks for the links Gord. Actually, the pushpit is pretty much built with connectors, ("T's", 90's and 3-ways), and is about finished. I’ll post some pics when i get the last few pieces together. What I am doing is carrying the pushpit railing forward as safety “railing” instead of cable across the stanchion tops, (3/16" cable at stanchion midpoints), and my only bend/curve is the section of tubing that has to go about midway on the boat between 2 and 3 stanchions. It needs to have a slight curvature in it to follow the lines of the hull...or at worst, have a few degrees in each end to align it to the "T's". (Since the lifeline below it runs in a straight line anyway!) Final section of lifelines from the 3rd stanchion to pulpit will be cable only. I've edited to add a link to a pic showing how i started the new lifelines last year. Note: the double stanctions aft are now being turned into the pushpit and it has double lifelines. What I am doing is replacing the top lifeline with the tubing to just forward of the cabin.
Thanks for the links Gord. Actually, the pushpit is pretty much built with connectors, ("T's", 90's and 3-ways), and is about finished. I’ll post some pics when i get the last few pieces together. What I am doing is carrying the pushpit railing forward as safety “railing” instead of cable across the stanchion tops, (3/16" cable at stanchion midpoints), and my only bend/curve is the section of tubing that has to go about midway on the boat between 2 and 3 stanchions. It needs to have a slight curvature in it to follow the lines of the hull...or at worst, have a few degrees in each end to align it to the "T's". (Since the lifeline below it runs in a straight line anyway!) Final section of lifelines from the 3rd stanchion to pulpit will be cable only. I've edited to add a link to a pic showing how i started the new lifelines last year. Note: the double stanctions aft are now being turned into the pushpit and it has double lifelines. What I am doing is replacing the top lifeline with the tubing to just forward of the cabin.
- Jan 22, 2008
- 519
Sand and the boat itself
As mentioned earlier, fill it with sand, then have a buddy anchor it in place alongside the gunwale of the boat, and bend it around using the boat itself as the form. It is amazing how easy this was to do. Use longer pipe that is required, as you may have to 'overflex' the short ends of the bends to match the boat gunwale. Then add T's, stantions, end caps as needed and voila!
As mentioned earlier, fill it with sand, then have a buddy anchor it in place alongside the gunwale of the boat, and bend it around using the boat itself as the form. It is amazing how easy this was to do. Use longer pipe that is required, as you may have to 'overflex' the short ends of the bends to match the boat gunwale. Then add T's, stantions, end caps as needed and voila!
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