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2004 TD42T3 Wagon
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Discussion Starter · #1 ·
I’ve got a couple of roobars that need straightening, bent on one side.
(One is heavier, probably called a “bulbar.”)
I’m wondering if it’s worthwhile trying to repair myself. Possibly by annealing the alloy and then straightening?
Anyone done this? What sort of torch would I need?
Otherwise, does anyone know of a place in Perth that does this sort of work? (NOR preferred.)
 

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nissan
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can you plz throw up some pics. allot is a bit of a pain to straighten out
 

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nissan
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alloy has a tendency to become very brittle once it has been bent and attempting to straighten often ends in tears. if you were to try it i would reccommend a size 6 or 8 tip on an oxy/acetylene set up. heat sparingly as alloy, being such a great conductor of heat, has a tendency to show very little signs of melting and then suddenly a large ammount will turn molten very quicky and fall away.

Also, being so soft i would reccomend using steady pressure rather than belting it with a hammer or something like that.

This link applies to aluminium, the specific alloy you have in you bull bars may be different but a huge part of it will be composed of aluminium and therefore applicable.

Hope this helps.

Working with Aluminum - Different tools, techniques needed in aluminum repairs - Search Auto Parts | Automotive News
 

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Discussion Starter · #4 · (Edited)
I have read some contradicting advice. Some say to anneal the alloy, so that it can be worked whilst cold. Others say to keep the temp below the annealing point and work it hot.

This is the critical one, without it I'd need to fit a bumper.
(The other I think may be beyond repair.)

Below:


Behind:



Above:
 

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nissan
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use oxi acetylene torch and overfueled flame.
Work it hot as the alloy wil most likely be ALMg.
This is the most used form because it's tuffer and oxidises less.
But it also stretches les and break or crack when bent.
 

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GU8 CRD
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If heating aluminium, here's a tip they taught me in welding school years ago. With an oxy-acet torch, run the flame over the aluminium with just the acetylene on. This will deposit soot over the aluminium. Now set the heating flame properly and start heating. Once the soot starts to disappear, the metal is at a temp of about 400 deg C, perfect for welding or working (aluminium alloys start to melt from around 560 deg C or so from memory). Just remember one thing with ali but - it gives no indication of when it is about to melt as it won't change colour or glow beforehand.
 

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You can use a propane torch jus as wel.
The trick is not to over heat.
With the oxi acetylene its easier to deposit a small layer of soot which burns away just before the critical temp.
 

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try on an old piesce of alloy first before you try the bar.
better safe than sorry
 
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