Help Bending a Sissy-Bar

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I'd like to try making sissybars myself but have no knowledge of metal. I'm thinking a bench top hydraulic press, scroll bender, hand drill and a vice could get me through. I need to replicate the thickness shown below (±3mm), but in gold.
IMG_2444.jpeg

No dimples where punched (or drilled?) as seen with cheaper bars and rather abrasion resistant or well finished.
IMG_2446.jpeg
Online gold tube salespeople point me toward 304 tube but they're not really familiar with my use of their product so I'm wondering.. is there a better quality or more suitable tube I should be bending? Could this setup work?
61gm5QRix-L._AC_SL1500_.jpgus-SDWGJSBG-40000001V0-original_img-v4-metal-bender-m100-1.2.jpg
Would the finish flake when I crimp and bend? If it makes a difference in finish durability I'm shooting for a 14K bright/yellow gold to match store-bought options for handlebars_Gold_PVD_coating.jpg.
 
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We do a ton of formed tube at one of the plants my company owns. Everything is plated after forming. Not saying it's completely impossible to do, but.......

You need forming dies for the proper OD to prevent crimping
 
We do a ton of formed tube at one of the plants my company owns. Everything is plated after forming. Not saying it's completely impossible to do, but.......

You need forming dies for the proper OD to prevent crimping
Does your company steer away from using pre-finished tube for that exact reason, ruined finish?
I was hoping to get away with a couple of arbor plates to press the ends flat then slowly drill them, grinding the edges. Might that not work? Am I wasting more trying to hack it rather than buying a die?
 
The metal tube has to slide through the dies as you are forming it. That makes scratches that you have to buff off before you plate.

You really can’t bend plated things much anyhow, or the plating will crack. The base metal and the plating metal have different physical properties and they don’t stretch the same.

Gold is more forgiving and it stretches a lot. But you are going to leave expensive gold on your die set, forming gold plated tubing.
 
Does your company steer away from using pre-finished tube for that exact reason, ruined finish?
I was hoping to get away with a couple of arbor plates to press the ends flat then slowly drill them, grinding the edges. Might that not work? Am I wasting more trying to hack it rather than buying a die?

The metal tube has to slide through the dies as you are forming it. That makes scratches that you have to buff off before you plate.

You really can’t bend plated things much anyhow, or the plating will crack. The base metal and the plating metal have different physical properties and they don’t stretch the same.

Gold is more forgiving and it stretches a lot. But you are going to leave expensive gold on your die set, forming gold plated tubing.


^^^^ This
 
I've done it with cold roll 5/8 s I believe I used. Used a conduit bender. You could use something like that polish it a shine gold metal cast for gold effect. Worked fine but forget what used to attach it to the bottom.
 
Thanks for helping me feel my way around in the dark @Ulu, @Captain Awesome . Which unfinished metal tube should I be looking to or away from for electroplating after bending? This is an example of the options suppliers present me with..
"A312/213 seamless tube SS 310S 309S 316 316L 316Ti 321 235MA 304 304L 904L 2205 2507".
Supplier says welded pipe has a better surface than seamless and suggested 304. Is that about right?

I've done it with cold roll 5/8 s I believe I used. Used a conduit bender. You could use something like that polish it a shine gold metal cast for gold effect. Worked fine but forget what used to attach it to the bottom.
Is there a benefit to bending cold rolled? I'm aiming for 20mm diameter, 3mm thick. I have indeed been considering the price of re-finishing gold tube, as you suggest, over plating unfinished stainless.

ALSO: Does anyone have American suppliers who aren't solely distributors? (does this exist?)
 
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Cold rolled has a smooth shiny surface,

Hot rolled is rough and black. It comes covered in black carbon and burnt oil.

I don’t remember using anything but astm A36 or A500 for structural work.

A312 is stainless for building kitchen equipment. . . 304, 310, 316 …all are stainless. Some resist salt better.

I did some engineering for company that built wine presses and huge wine tanks. 1,200,000 Litres ! They used 304 stainless all the time. I think it was the acid resistance that made it popular.

“L” is low strength, and is easier to bend. Like 304L. It isn’t tempered as much.
 
Thanks for helping me feel my way around in the dark @Ulu, @Captain Awesome . Which unfinished metal tube should I be looking to or away from for electroplating after bending? This is an example of the options suppliers present me with..
"A312/213 seamless tube SS 310S 309S 316 316L 316Ti 321 235MA 304 304L 904L 2205 2507".
Supplier says welded pipe has a better surface than seamless and suggested 304. Is that about right?


Is there a benefit to bending cold rolled? I'm aiming for 20mm diameter, 3mm thick. I have indeed been considering the price of re-finishing gold tube, as you suggest, over plating unfinished stainless.

ALSO: Does anyone have American suppliers who aren't solely distributors? (does this exist?)
3mm thick, as in 3mm wall thickness? Stainless? And you plan to bend it by hand at a somewhat small radius for 180 degrees without crushing it?

Sounds like a pretty big ask. Have you ever tried to bend tubing that thick?

If I'm understanding it, you plan to bend up a sissy bar with hand tools. While not impossible it won't be easy either. 3mm is WAY too thick to work with at home. I'd only use stainless if I planned on poilishing it and using it bare - if you're going to plate it anyway why not use carbon steel? Easier to work with and cheaper.

I'm no expert on this but I'm going to guess that you're going to crush the tubing if you try to bend it into that shape. To avoid this some guys will fill the tubing with sand or birdshot before bending to keep it from being crushed. I've even heard of ice being used but I'm not sure how they kept the ice from bursting the pipe as it froze.

I've bought tubing from these guys before but haven't checked to see if they have the stuff you're looking for.
https://www.speedymetals.com/c-8276-round-tube.aspx
 
Have you ever tried to bend tubing that thick?
if you're going to plate it anyway why not use carbon steel? Easier to work with and cheaper.
I'm going to guess that you're going to crush the tubing if you try to bend it into that shape.
I've not tried bending tube yet. As stated, new to and feeling my way around metal so this is all extremely helpful. I'd focused on stainless for the base shine as it seems the color of many coatings are affected by the underlying reflection or lack there of. My thought process was, if I can find polished tube to start with there may be less work coating and plating the section I form rather than coating the entire piece. Also for its rust resistance because these will see all seasons. I'll switch gears and start looking at carbon steel unless you can suggest a more polished option.

I'd also been scoping something like this to bend with. Would you suspect your suggested anti-crushing techniques are necessary with these presses as well or was it strictly a matter of changing my proposed material?
2in-Hydraulic-Pipe-Bender-Tool-Hire.jpg
 
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I've not tried bending tube yet. As stated, new to and feeling my way around metal so this is all extremely helpful. I'd focused on stainless for the base shine as it seems the color of many coatings are affected by the underlying reflection or lack there of. My thought process was, if I can find polished tube to start with there may be less work coating and plating the section I form rather than coating the entire piece. Also for its rust resistance because these will see all seasons. I'll switch gears and start looking at carbon steel unless you can suggest a more polished option.

I'd also been scoping something like this to bend with. Would you suspect your suggested anti-crushing techniques are necessary with these presses as well or was it strictly a matter of changing my proposed material?


Bending the tubing is going to damage the surface. You will likely have scratches and maybe even gouges depending on your tooling. I wouldn't worry too much about surface finish of the raw tube, you're going to end up polishing it anyway. Even if you buy 300 series stainless it won't be polished when you get it, unless you pay extra to buy it in polished form. Stainless isn't naturally shiny, it needs to be polished.

Crushing happens because the metal has to go somewhere when it bends. When you bend a tube, the centerline doesn't change length, but the inside and outside surfaces do. Lets's say you're bending a 2" tube on a 4" radius. The 4" is the dimension of the bend at the centerline of the tube. If I'm looking at it from the top and bend it to the right, the right side of the tube will be on a 3" radius, the left side will be a 5" radius. In order for the tube to bend, the outer edge has to stretch, and the inside edge has to compress if you want it to stay round. If you leave it to it's own devices, you get the outer surface going flat instead of round and the inner dimpling and wrinkling. Or the outer will tear and the inner will just kink, or any number of other things.

The deeper the bend, the more distortion you're going to have. It doesn't matter what tool or material you use, the material has to stretch and compress. You've probably seen the term "mandrel bends" or something similar. The mandrel is a piece of tooling that goes inside the tube to hold it's shape as it's bent. If there is nothing serving as a mandrel, you're going to get crushing/collapsing/folds/dimples as the metal stretches and compresses. And with a mandrel you can get tears when the material won't stretch like you want.

Material makes a difference but you're going to get distrotion no matter what material you use. Anything with walls thick enough to not crush won't be something you want to bend at home.

The tooling you show will crush tubing just like every other non-mandrel bender. You also have to be able to buy specific dies for the specific size tubing you plan to use. FYI tubing and pipe benders use different tooling because they call out sizes differently. One uses the ID for the stated size, the other uses the OD for the stated size. The tooling has to fit the OD of your tube. Close will not be close enough. If you are using 20mm OD tubing you need 20mm dies for your bender. If you change to 0.75" OD tubing, you will need 0.75" tooling. I'm guessing imperial sizes will be easier to find in the US than metric, but it's been a long time since I've looked for it in either units.

Another issue with the tool you posted is it has to be narrow enough that you can bend the tubing 180 degrees and still clear the tool, as in it needs to be narrower than the space between the finished sissy bar.

FWIW - I worked in the automotive exhaust industry for about 30 years. Bending stuff was never my job but I've had to deal with it quite a bit over the years. Have you ever seen exhaust pipes with what looks like a corrugated surface on the inside of the bends? That's another way to use up the excess material when it bends. It's gotta go somewhere.

Honestly, if I was going to bend up a sissy bar and only planned on making one of them, I'd use solid rod. Not kidding. Heat it up and bend it around whatever you have around that's the right diameter. OR... fill the tubing with sand and treat it like a solid bar. Forget all the tooling and just use heat and brute force.

EDIT: If you go the sand filled route, you'll likely have to fill it up and cap the ends so the sand doesn't move when you bend the tube. If you do this, leave a vent hole somewhere. Moisture in the sand can turn to steam when you heat everything up and steam = pressure, you don't want a pressurized tube to burst/tear and shoot hot sand everywhere.
 
Moisture in the sand can turn to steam when you heat everything up and steam = pressure, you don't want a pressurized tube to burst/tear and shoot hot sand everywhere.
Oh heck yeah, the instructions were very specific about making sure that sand was dry before it went in
 
I concur! Best help I've found online dude. THANK you.
I had figured that were I to invest in this equipment I may as well plan to make many so I probably won't be bending it by brute force. But this is the information I needed. Even if I shy away from this adventure it helps me understand what goes into making them and why it's been so hard to find locals who want to get into it. I'll study up on all this but it sounds like I'm getting beyond my work space's capability. At this point ordering a hundred or so custom made in China is sounding equally expensive. Hate to do it but my resources are limited.
 
Agree, pack it with sand, bend it around a pole. Put a piece of leather or heavy vinyl between the pole and the tube.

I'm considering making one out of 1/2 conduit, the galvanized will polish up to a "nickel-ish" finish. Flatten the nds and shove a flat plate in, drill thru.
 
Agree, pack it with sand, bend it around a pole. Put a piece of leather or heavy vinyl between the pole and the tube.

I'm considering making one out of 1/2 conduit, the galvanized will polish up to a "nickel-ish" finish. Flatten the nds and shove a flat plate in, drill thru.
and take your time....dont try to bend it all in one hit, I like the sand idea!!!
 
I'd been steering away from conduit as it seems too soft and my issue is breakage. But at this point the resources required are not in my wheel house so I'm back to sourcing, local first.
 

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