[TheForge] Brazing vs welding

Sun Nov 17 12:02:02 2002

Pete  and John,  I was told that nickel rod leaves a layer of carbon under 
the weld and is not as strong as brazing?  In any case this is a close 
fitting joint  and I am hoping that means brazing will be strong.   If you 
believe the data from harmony & co a close fitting brazed joint is stronger 
than the parent metal. Since these are mating halves of a cast iron 
fracture I wasnt planning to file or grind the joint , just degrease and 
pickle to clean it.   Does this sound right?  Does it pay to tin the 
surfaces before joining?

Adam

At 09:42 PM 11/16/2002 -0800, you wrote:
>At 10:58 AM 11/16/02, you wrote:
>
>Adam, there is a special brazing flux for cast iron..There's an 
>old  blackened red  can that I've had for years that was for that but the 
>label was burned off years ago..theres some crusty black flux powder in 
>it.  Might ask the Anti-borax Co.. Most Important for that sort of repair, 
>is de-greasing.
>A stronger repair is using nickle rod and a stick welder...an old method 
>was to buy cast ( literally) iron rods for torch use and use a similar 
>cast iron flux as for braising.
>
>Re Harbor Fright prices..."can't hardly go wrong at those 
>prices".........Oh yes you can!
>I figure that the  % of HF tools that are utter crap about equals the $ 
>you save on the rest..and you have no guarantee on the remainder.
>
>Chris; In years gone by, I've used 2 kinds of brazing rod made for stick 
>welders. One was an aluminum bronze. No idea if it is still available.
>
>John CH;  The advantage of using TIG would lie in the shorter time it 
>takes to reach heat,the more confined heat propagation ( and heat shock) 
>and the lack of flux because the shielding gas keeps the oxy away. Flux 
>cleanup can be a real nuisance.
>
>This sage advice is probably worth about what you paid for it..BG
>
>Pete
>
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>>a very informative post.  Pete, what do you suggest for brazing cast 
>>iron?  I have a couple of vises  (actually I have a LOT of vices)  that 
>>failed where the moveable jaw joins the slide bar.  Would like to try and 
>>repair them.
>>
>>The two drawbacks I have found with brazing forged work are:  cant work 
>>the piece after brazing if it means heating the join  and that the colors 
>>dont match.  OTH being able to disassemble the joint w/o damaging the 
>>components can be very handy
>>
>>Adam
>>
>>
>>At 08:58 PM 11/15/2002 -0800, you wrote:
>>>At 06:20 PM 11/15/02, you wrote:
>>>
>>>
>>>There are a bunch of specialized fluxes available for brazing...or you 
>>>can use the  same borax you forge weld with.  For gas welding , flux 
>>>coated rods are handy. You can get rods to match a range of colors and 
>>>rods that melt at different temperatures so that you can build complex 
>>>structures is stages. ....
>>
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