Im assuming there made from sheet metal with the 2 halves cut out, rolled into shape somehow then welded... But yea how do you work out what shape to cut the sheet and then how do you bend it into shape like that?!
How do they fabricate bends?
Started by
_Viper_
, Dec 02 2010 08:26 AM
11 replies to this topic
#1
_Viper_
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Posted 02 December 2010 - 08:26 AM
Hey guys, Im just wondering how do people make fabricated bends? like the one pictured...
Im assuming there made from sheet metal with the 2 halves cut out, rolled into shape somehow then welded... But yea how do you work out what shape to cut the sheet and then how do you bend it into shape like that?!
Im assuming there made from sheet metal with the 2 halves cut out, rolled into shape somehow then welded... But yea how do you work out what shape to cut the sheet and then how do you bend it into shape like that?!
#2
dattoman
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Posted 02 December 2010 - 09:42 AM
Millions of dollars worth of machinery ??????
#3
_nicko61_
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Posted 02 December 2010 - 10:02 AM
you can buy pipe bends for exhaust and turbo set ups so i assume you can get it in alloy, the half curve in length way as seen in your pic is something i have not seen for sale, but any pipe place can sell you the 180deg curves and you cut out what you need to get desired curve and weld them up.thats how some make there own extractors and ive seen them in 4" as well for turbo applications
#4
Toranamat69
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Posted 02 December 2010 - 10:26 AM
For really tight mandrel bends in Steel or Alloy, you cannot do them on a mandrel bender so they stamp half toroids (donut shapes) out of sheet and then weld the top and bottom half together - you use the same method as you do with mandrel bends and just cut off how many degrees you need to make up the piping and joint it up with nice welds.
http://www.jntperfor...ex_c269221.html
http://www.jntperfor...ex_c269032.html
http://www.xtremeaut...?idCategory=361
http://www.jntperfor...ex_c269221.html
http://www.jntperfor...ex_c269032.html
http://www.xtremeaut...?idCategory=361
#5
_mervex_
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Posted 02 December 2010 - 10:56 AM
HI,the bends in the pic are metal spun then welded together to for a donut.mandel bends are a straight tube pulled around a "half" inside tube with a steel ball inside.Have a look on Utube to see it .Check out "nissin tube bender" on Utube, more like a mind bender. mervex
#6
ls2lxhatch
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Posted 02 December 2010 - 11:02 AM
If you want to have a look at some donuts on the shelf in Perth.
GoGear in Mount Hawthorn have a reasonable selection of half and full donuts in steel and aluminium.
Searle Race Equipment in Welshpool have a small selection.
GoGear in Mount Hawthorn have a reasonable selection of half and full donuts in steel and aluminium.
Searle Race Equipment in Welshpool have a small selection.
#7
TerrA LX
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Posted 02 December 2010 - 01:58 PM
Mmmmm doughnuts
#8
_Bomber Watson_
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Posted 02 December 2010 - 05:47 PM
I dont think he wants to buy them, 3 year olds know where to buy them from, i think he was asking how they were made....
Toranamatt69 and Mervex seem to be on the money.
Cheers.
Toranamatt69 and Mervex seem to be on the money.
Cheers.
#9
ls2lxhatch
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Posted 02 December 2010 - 08:01 PM
Bomber, Thank you for your words of wisdom.
#10
_Viper_
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Posted 02 December 2010 - 08:03 PM
Yea ive seen donuts and all that before, but they are seamless.... Ive seen bends like the one pictured a few times and I thought people in their own workshops were fabricating them and Was wondering how they do it.
So from what I gather workshops/people buy them like that and some specialised workshop makes them...
Whats the benefit of them (if any) compared to off the shelf pre-fab seamless bends or just using donuts.
So from what I gather workshops/people buy them like that and some specialised workshop makes them...
Whats the benefit of them (if any) compared to off the shelf pre-fab seamless bends or just using donuts.
#11
ls2lxhatch
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Posted 02 December 2010 - 09:05 PM
The bend above has been made from a half donut or a welded donut.
It probably would have looked better is it was made from a seamless full donut. I guess some workshops just stock half donuts as they are more versatile or welded donuts are cheaper than seamless.
The main benefit of a donut vs a mandrel bend is as ToranaMatt69 said, the donut has a smaller radius bend than is possible with a mandrel bending machine. A donut is also more versatile than a off the shelf mandrel bend as you can cut it to any angle you want.
Prestige Exhaust used a full seamless donut to get my exhaust over the diff. Their mandrel bending machine could not produce a tight enough bend.
It probably would have looked better is it was made from a seamless full donut. I guess some workshops just stock half donuts as they are more versatile or welded donuts are cheaper than seamless.
The main benefit of a donut vs a mandrel bend is as ToranaMatt69 said, the donut has a smaller radius bend than is possible with a mandrel bending machine. A donut is also more versatile than a off the shelf mandrel bend as you can cut it to any angle you want.
Prestige Exhaust used a full seamless donut to get my exhaust over the diff. Their mandrel bending machine could not produce a tight enough bend.
Edited by ls2lxhatch, 02 December 2010 - 09:17 PM.
#12
_Bomber Watson_
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Posted 02 December 2010 - 09:19 PM
Bomber, Thank you for your words of wisdom.
No worries at all mate, anytime.
Only problem i have had with the welded half doughnut type ones is if you have to try to make them not round, ie making them fit into a internally wastegated turbine flange or similar, they tend to split along the weld.
I dont get exhaust shops to do my work, i do it myself, most people wouldent have found that problem.
Cheers.
Edited by Bomber Watson, 02 December 2010 - 09:26 PM.
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