Re: Bike Locks/security Thread...

Postby pokey on Sun 1/May/16 8:36pm

Scotty wrote:Now that depends on whether Dougal was wearing his owners hat or not. :lol:

Now I'm no injuneer or reefer-roller, but I do know that D used to do things like finite element analysis in his spare time for a laugh.


Yeah I laughed at 'the impact resistance of cardboard', imagine if shit got reign man real and it came to swordfight.

Scotty wrote:The man knows a bit about this sort of thing. :rolleyes:


Have you seen the Life of D? His mum believes he's the messiah and drives the price of fish through the roof stocking up for party tricks.
pokey
Member for: 1 year 10 months

Re: Bike Locks/security Thread...

Postby pokey on Sun 1/May/16 8:39pm

Dougal wrote: I used Heat Treatments Ltd in Auckland for the T6 treatment.


How did they feel about the lack of jig and prospect of straightening t6 tube? Did you have to sign a disclaimer? What sort of prep did they require?

Dougal wrote:I I did the weld prep myself and paid a talented welder to do the welding. While I can weld steels quite well I haven't ever tried TIG welding aluminium and didn't want to practise on a bike frame.


Probably best to reserve judgement on such then and not strut about in your Casey Jones hat blowing your whistle. Ask your talented welder why a 'real engineer' proclaiming welded t6 heat affected zone is embrittled is laughable, he may ask if he did it himself.
pokey
Member for: 1 year 10 months

Re: Bike Locks/security Thread...

Postby shmoodiver on Sun 1/May/16 8:55pm

are you sure he's not gumby?
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"There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die."
Member for: 10 years 3 months

Re: Bike Locks/security Thread...

Postby Dougal on Sun 1/May/16 9:40pm

pokey wrote:
Dougal wrote: I used Heat Treatments Ltd in Auckland for the T6 treatment.


How did they feel about the lack of jig and prospect of straightening t6 tube? Did you have to sign a disclaimer? What sort of prep did they require?


It was 10 years ago now (still got the frame, it's only seen commuting duty lately). It was just another job for them, I don't remember anything special in instructions except for T6.

pokey wrote:
Dougal wrote:I I did the weld prep myself and paid a talented welder to do the welding. While I can weld steels quite well I haven't ever tried TIG welding aluminium and didn't want to practise on a bike frame.


Probably best to reserve judgement on such then and not strut about in your Casey Jones hat blowing your whistle. Ask your talented welder why a 'real engineer' proclaiming welded t6 heat affected zone is embrittled is laughable, he may ask if he did it himself.


This frame had been welded twice prior without heat-treatment and it could have been well described as badly beaten scrap. Complete with ovalised head tube so it was no surprise it cracked. The first time it was welded it cracked so soon after welding that they split and opened a piece of aluminium pipe to sleeve the part they welded and cracked before.

Now apparently the welder that did that job was a great welder who never had any come backs. Not surprising really as I'd never let him have another go either. :crazy:

So it took some time cutting, filling and smoothing to get rid of all that crap. Plus taking the cracked areas back to clean metal, radiusing out the ends so it would have nice geometry for new weld filler.
The welder I used did a fantastic job, he was also of the "nah, don't need that heat treatment" opinion. Many think it just needs a slow cool down after welding. But when you explain that this alloy contains copper which clumps together and "unsticks" when it's heated by welding and you need a heat, soak, quench and then age to unclump the copper and spread it back out again. Well then they accept that you might know what you're on about. :)

No issues since. I epoxied in a headset cup to deal with the oval head-tube and chased the BB threads and that was it. Mrs Dougal rode the frame for a couple of years, then a family member commuted on it for a bit. I've still got it here.
Last edited by Dougal on Sun 1/May/16 9:46pm, edited 1 time in total.
Dougal
Member for: 14 years 6 months

Re: Bike Locks/security Thread...

Postby Dougal on Sun 1/May/16 9:45pm

Here's a pic I found of it after welding but before heat-treatment. It was cracked and repaired under the head-tube and where the seat tower meets the top of the boom-tube. The ugly pipe taco was welded over this seat-tower repair.

All the paint was burnt off during heat-treatment.

IMG_2873.jpg
Dougal
Member for: 14 years 6 months

Re: Bike Locks/security Thread...

Postby wachtourak on Mon 2/May/16 7:08am

Image
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"IMDABES"
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