Blow torching welds...
 

[Closed] Blow torching welds on raw steel frame to get colouration?

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Local powder coater says a chap brought in a raw steel motorbike frame and had blow torched the welds/tube ends to get the purple colouration back. Any one heard of this or done it?

Like this:

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Thanks


 
Posted : 02/04/2020 12:02 am
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^i first thought they were genuine weld heat marks but on a second look - there isn’t one for the tank mount stud so maybe someone did trace the welds with a torch? It would need to be something warm and focused to get the heat in quickly - and remember heat isn't your friend when talking of the general metallurgy of bicycle tubes.

I’d just give it a polish with a proper 3m scotchbrite cloth and then clearcoat, you’ll be happy with it.


 
Posted : 02/04/2020 12:16 am
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Thanks Rusty. Think I’ll go with the safer option here! Out of interest it’s Reynolds 853 if that makes any difference regards heat


 
Posted : 02/04/2020 7:44 am
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It'll only be braised rather than welded if its 531? Getting enough heat into it to get colouring like that would melt the braise I would have thought.


 
Posted : 02/04/2020 11:25 am
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Thanks rockhopper. It’s 853 if that makes any difference


 
Posted : 02/04/2020 12:40 pm
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I've been down the clearcoated steel route, and it was repainted black not long after, as it was rusting like mad.


 
Posted : 02/04/2020 12:52 pm
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Clearcoat might work better on 853 though, it’s stainless, so is unlikely to rust badly.
Id be wary of using heat for discolouration purposes though.
I’m not a metallurgist though, so could be talking complete shite. 😂😂


 
Posted : 02/04/2020 1:00 pm
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Is 853 stainless? Thought 953 was the super flash stainless steel?


 
Posted : 02/04/2020 1:03 pm
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853 is not stainless.


 
Posted : 02/04/2020 1:05 pm
 goby
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nope definlty not, 853 Seamless Air-Hardening Heat-Treated Steel and 953 stainless.


 
Posted : 02/04/2020 1:16 pm
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My mistake 😂😂


 
Posted : 02/04/2020 1:19 pm
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Right then...scotchbrite it is then!


 
Posted : 02/04/2020 3:44 pm