DIY Pipe Bending

[Fishballs]

Hey guys, just after some advice on pipe bending.

Me and a mate have purchased a hydraulic bender and mig welder and wanted to weld and bend up some steel bars for rocksliders and some ladder bars for the tray backs. The steel for the ladder bars are 76 OD medium galvanised. For the rock sliders were using 32 NB medium black.

Basically we tried bending the 76 OD mm and it folded and kink and looks crap.
Ive read on here( after the fact) to pack sand into the tube and something about a draw bender.

Is the hydraulic bender able to do good bends on this type of steel or do we need different type of steel?

Thanks

[TazMAV]

what size die are you using for the bending

[Harb]

With a Non forming Bender which I assum you are using.......the ones with half moon shaped formers and two rollers only, pipe wall thickness is the answer.
You will be hard presssed to do tight bends on thin walled tube at all.
The thicker the pipe however, it does get easier.
A solution if you have to do the bend is to fill the pipe with sand and weld caps on the ends so it is similar to a solid bar. The pipe must be totally filled for this to work.

Bending large OD pipe is an art in itself hence most people opt for factory made mandrel bends and weld them into the job to save the headache..........

Galvanising changes to surface hardness, which makes matters even worse..........

cheers
John

[Fishballs]

Thanks guys.

The die we are using (tasmq) I assume you mean that half moon is suited to fit. The wall thickness of the gal pipe is 3mm.

Buying the bends sounds alot easier. We were going to go this way but thought the bender would save us money in the long run.

The whole sand thing sounds good but I think it would be alot of effort because off the 3.5m lengths we are trying to bend.

Thanks for the replies.

Anyone want to buy a pipe bender in Sydney. Only used once.

Cheers
Tim

[Harb]

Thery work great on smaller dia thicker walled tube........

cheers

[Fishballs]

Thanks HARB.....mate just roughly, does it cost much to get mandrel bends and how to the TJM,s and ARB,s out there bend up their bar work or is it mandrel bent/welded too.

Thanks

[TazMAV]

The best thing you can do is use thick wall pipe with the right size dies and yes it is the half moon bit I am talking about. It may be that somethings no right some where. We have a joint down here that will bend near anything from pipe to rhs as well as channel and rsj the machine cost the heaps from Sweden or somewhere, there must be someone in Sydney that can bend your pipe for you that way you get a better job than all that welding.

[4runner8]

keep the bender, as harb said smaller dia pipe they work fine. as for the 76mm you probably got a half decent bend on the first one?
one thing to do is get decent dies, the cheap benders come with cheap dies. with the 76mm the wall of the dies flexs out causing an increase in pressure applied to the inside centre of the bend causing the kink. i had cheap dies and after one bend of 65mm the die had stretched open approx 6mm.

[Fishballs]

Ill check that

cheers 4runner8

[safari wagon]

i had this problem last week. certain dies for certain sizes. with out going to the trouble of packing with sand, pipe has a certain radius length before it will kink every time. good luck to ya.

[sudso]

You can try shimming the die with tin fishballs, to make the radius smaller to suit the lighter gauge pipe.

You need medium gauge pipe as a minimum with your run of the mill benders as all pipe sizes are given as nominal bore, not outside diameter like tubing, so the manufacturers of benders usually make their dies to suit the heavy gauge pipe, which has a larger OD than medium or light gauge.

cheers, sudso

[tommyk]

has anyone got any pics of the bends those cheaper benders can do?

[Harb]

Thanks HARB.....mate just roughly, does it cost much to get mandrel bends and how to the TJM,s and ARB,s out there bend up their bar work or is it mandrel bent/welded too.

Thanks


depending on the size and the thickness it can vary heaps.....if its a one of custom job, I supose its worth it and depending on the thickness of the tube required you can get different size "donuts" yes they do look like donuts,find them here http://www.chassisshop.com/pdf/112-113Donuts.pdf and you just cut the radius out of the donut you need then weld them in....

The arb and tjm stuff would be made with a mandrel bender or similar that completely encases the pipe in the area being bent...such as the pictures below, unless they have the crushed inner curve, in which case they are using a similar bender to yours, but smaller thicker tube.


The most simple method is this.........using rollers that "roll" the pipe around a mandrel via the good old strong arm method .............

http://img291.imageshack.us/img291/2520/manualbenderkm7.jpg (http://imageshack.us)


or if you have a good relationship with your bank manager, you could get this, that does the whole process using hydraulic's........

http://img181.imageshack.us/img181/5780/mandrelbenderev4.gif (http://imageshack.us)

[sudso]

Noice!
Mandrel benders can draw a pipe in a tighter curve than those poxy cheapo die's too.

[kiemy75toyo]

Hi all,
Fishball, give this ago. Put the sand in (make sure its DRY SAND). Plug both ends with wood, and heat the tube up before you start bending it. And you really do need the good (thicker) dies.

[Pog]

You can try shimming the die with tin fishballs
Took me a minute to work out WTF you meant by that! :D

[Harb]

where do you get these "Tin Fishballs" ?