Topic: Re: PIPE Bending from the SEABEX ONE thread (Read 6033 times)

Unsinkable 2 · « **on:** July 15, 2015, 10:03:58 pm »

Topic split from: Re: SEABEX ONE scratch build
http://www.modelboatmayhem.co.uk/forum/index.php/topic,50787.msg530036.html#msg530036

Like it Ken

.

How do you bend the pipes without creasing as I will need to make some bent brass tubes soon.

Thanks. U2

ballastanksian · « **Reply #1 on:** July 15, 2015, 11:00:05 pm »

You can get spring type tube benders that go over the tube like a sleeve and then you bend away. Remember to anneal your tube regularly of you are making complicated curves in one piece of tube to prevent tearing.

Tug-Kenny RIP · « **Reply #2 on:** July 16, 2015, 09:33:11 am »

I have a pipe bender which I hold in the vice. It's Ok down to 3mm pipes but won't do tighter diameters, especially on 2mm or smaller.

Here's a test piece to show it in action.

hope this helps

ken

derekwarner · « **Reply #3 on:** July 16, 2015, 09:56:18 am »

The Du-bro benders suit 1/8" & 5/32" OD tube...& @ less than $20 AUD each represent good value .......verses the cost of incorrectly set tube wastage....

The 1/8" bender provides an approx ~~ 6.5 mm ID bend radius, the 5/32" bender provides an approx~~ 11.5 mm ID bend radius

The Du-bro spring tube benders technically do work, however it is near impossible to produce two uniform radius bends

I can achieve 5/32 " copper bent to 180 degrees with say 4 x annealing processes per bend, cold drawn brass however is less forgiving with say 90 degrees max....

...again with 4 x annealing processes during that bend

Many will argue to anneal is to get the tube to cherry red, then quench in water, I was taught to raise to the same cherry red then let cool naturally

Another tip is to pre polish the tube [by way of the bend] in a circumferential manner, not by longitudinal motion......the thought here is that you are minimising that minute surface marking that can lead to the dreaded

wrinkling......

Another point with these Du-bro benders is that the aluminium tube handles unscrew from the body of the bender thus allowing close centred compound bends

Lagging the tubing can hide a multitude of sins

......Derek

Brian60 · « **Reply #4 on:** July 16, 2015, 06:14:51 pm »

Those are nice benders Derek, who makes them, I'm assuming they are Australian? I wouldn't mind a set if there is a European distributor.

I have one of those that Ken shows above but the best radius you can manage is around 30mm or more, I'd prefer to get in tighter.

derekwarner · « **Reply #5 on:** July 17, 2015, 12:03:12 am »

Brain....they are from the American WWW.DUBRO.COM .....you can get them world wide

The 1/8" ...part number 758A ranges from $11.00 to $21.00 on various WEB sites.......

The former hub is accurately machined brass, the former profile of the body is some high density synthetic so you do not experience any tearing of the outer radius during the bend.......

I understand 4 x annealing's in brass for 90 degrees may sound over the top

.....but it works...... Derek

Unsinkable 2 · « **Reply #6 on:** July 17, 2015, 08:39:09 am »

Excellent, well done Derek I just ordered a pair of the 1/8 tube benders...... But guess what, a bit of searching on eBay America (eBay.com) and I found a new set for 10.25 pounds INCLUDING POSTAGE

I changed the setting at the top of the page to 'cheapest for item and postage combined' but it still came to 15 dollars per item and 12 dollars postage. A little lower down and suddenly there they were

.

The Dubro website want a bit more and the Australian eBay are trying it on with 64 and 82 dollars postage. So unless an Australian dollar is is about 5p it works out a tad expensive.........

Thanks again to Derek for the heads up........ U2

Unsinkable 2 · « **Reply #7 on:** July 17, 2015, 08:48:44 am »

Oh dear I just tried to paste something from Wikipedia and it all went wrong. Here it is in brief

Annealing copper silver steel and brass can all be done by heating and letting it cool in air ...... BUT Only copper silver and brass can be heated and quenched in water for the same effect.

Ferrous metals such as Steel cannot be heated then quenched it has to cool slowly........ Wikipedi not me

. U2

Unsinkable 2 · « **Reply #8 on:** July 17, 2015, 09:09:05 am »

I just found the 5/32 for 13.00 pounds including postage so I ordered those too

....... Oh oh missus is coming got to go......... U2

Brian60 · « **Reply #9 on:** July 17, 2015, 11:55:46 am »

You trying to buy up the world supply US2?

derekwarner · « **Reply #10 on:** July 17, 2015, 03:55:06 pm »

Guys....not trying to kill Kens SEABEX thread, so will start a new topic on annealing brass...........Derek

Brian60 · « **Reply #11 on:** July 17, 2015, 05:46:46 pm »

Quite correct Derek. 'Annealing Metals' started in engineering section.

Brian60 · « **Reply #12 on:** July 17, 2015, 05:48:29 pm »

As a spinoff not to contaminate a Ken's build thread on the Seabex.

How do you go about annealing the various metals we use, any tips or hints you can give?

Brian60 · « **Reply #13 on:** July 17, 2015, 05:54:35 pm »

To carry on from the Seabex topic, I have also ordered the tubing benders from the States, 1/8th for 10.25 inc p&p and the larger one for a shade over 13 quid, can't go wrong at those prices.

So what are peoples thoughts on annealing tubing before attempting to put a tight radius in a tube?

Mark T · « **Reply #14 on:** July 17, 2015, 08:59:54 pm »

Annealing - I used to have to do a lot of this when I was an apprentice. The process is designed to increase the flexibility of a metal so that it can be bent or shaped without it cracking or creasing which in turn retains the metals initial properties.

The process was always to heat the metal until glowing and then allow it to cool naturally. This allowed the structure of the the metal to relax which then allowed it to be manipulated with ease. This is best seen with copper pipe which after being annealed is like putty to bend.

The only fly I found in the ointment was work hardening. After a few manipulations the metal begins to harden again and so requires annealing again. These are only my experiences of using this technique.

Mark T · « **Reply #15 on:** July 17, 2015, 09:04:33 pm »

Quote from: Brian56 on July 17, 2015, 05:54:35 pm

To carry on from the Seabex topic, I have also ordered the tubing benders from the States, 1/8th for 10.25 inc p&p and the larger one for a shade over 13 quid, can't go wrong at those prices.

So what are peoples thoughts on annealing tubing before attempting to put a tight radius in a tube?

Hi Brian - If you need a very tight bend pack the tubing with fine sand after annealing. Sometimes you really need to pack it in with a small nail or something similar as long as its packed tightly. Then bend it as tight as you like. When you have the require bend just get the sand out - this part is sometimes easier said than done but the pipe will remain round.

Unsinkable 2 · « **Reply #16 on:** July 17, 2015, 09:45:34 pm »

Brian, Glad you found the pipe benders for the same price.

ANNEALING......
Copper, Silver, Brass and Steel can all be heated until glowing red and left to cool to room temperature in still air. Copper,Silver and Brass can also be quenched in water.

Ferrous metals such as Steel must be cooled slowly...... Just repeating what I researched on the web...... U2

Brian60 · « **Reply #17 on:** July 17, 2015, 10:27:35 pm »

I think the toolshop (PowerHobby) I ordered from must be the same as yours U2, ebay the font of all things allegedly cheap

derekwarner · « **Reply #18 on:** July 17, 2015, 10:50:56 pm »

Guys.....as an apprentice...each year one of my jobs during the 3 week shut down of the copper & brass tube mill was to ride the 300 foot long enclosed continuous inert gas charged, induction electrically heated tube annealing furnace

...[these tubes were destined for domestic water]

The gas was to ensure the tubing remained a mirror bright, without any form of internal or external surface oxidation, last 20 foot was a natural cool down segment...before reaching the open atmosphere

With respect to heating and water quenching, this is done to achieve a dual physical metal matrix....an example here is the manufacture of shell casings....yes for large ordnance.......the casings are punched from annealed brass which is horrendously work hardened during that process, then the interface of the casing where the projectile is mated is the reannealed and water quenched

The purpose of this is to maintain the high mechanical strength and rigidity of the casing, with the exception the annular band are where the projectile is swaged

From a metallurgical point, you certainly can heat then water quench brass tubing to create an annealed state, however the intergranular metal structure is a far more defined by position, & hence for our purposes I choose to anneal slowly.....this then provides a longer transition band between the planned area to be bent

Water quenching of 1 ft long lengths of our model tube also has an influence in causing buckling of the lengths, which then also needs to be rerolled on the teflon kitchen chopping board...which does not impress your spouse

.......

Without the luxury of a 7000 kW induction heater in the kitchen, I use canister gas for the heating and yes this does cause oxidation blackening, however a simple polishing with a non abrasive liquid removes this and provides a smoother surface for the Teflon body of the bender to slide over....prior to the reapplication of the TEXTA colour marks

Naturally if Ken would transfer a few postings to this thread would be appreciated

.................Derek

Thank you Derek. The relevant postings have been brought over to this thread.

ken

Brian60 · « **Reply #19 on:** July 18, 2015, 07:32:06 am »

What is TEXTA Derek? I'm assuming its a marking fluid? Do you use this to mark your bend point and line up with the bender? I usually make do with a felt tip/marker pen.

RAAArtyGunner · « **Reply #20 on:** July 18, 2015, 07:42:27 am »

Quote from: Brian56 on July 18, 2015, 07:32:06 am

What is TEXTA Derek? I'm assuming its a marking fluid? Do you use this to mark your bend point and line up with the bender? I usually make do with a [b]felt tip/marker pen.

AKA, Aussie Texta

derekwarner · « **Reply #21 on:** July 18, 2015, 08:28:54 am »

.....yes...when we mark out the primary length of the tube/length to be annealed.......the big NO NO, is to place a physical mark or scratch on the surface as this will invariably be the root cause of a crinkle or fracture ........so we use a TEXTA felt tipped pen

Only problem is the ink in the pen is usually a volatile fluid that burns off.......so after the annealing all of the reference marks are gone??????

Always good to have a thumbnail sketch to re-establish your references

....

If you look at the image of the DUBRO bender with the RED line ......the leading face on both halves of the bender body is the same flat face plane as the axis as of the inner round former element........ so with a little practice this is where you line up the TEXTA line to the commencement

point of the bend ........

This is the only method to achieve bends of repetitive set or length etc

......Derek

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Author Topic: Re: PIPE Bending from the SEABEX ONE thread (Read 6033 times)