[TheForge] Welding and grease

[Peter Fels And Phoebe Palmer]

That's about what i would have answered if someone had asked me, but....
Wouldn't the much higher temperatures more than make up for the 
shortened time of heat exposure?
I'd thought that any chemical reactions or vaporization that were going 
to happen to the surface of metal under a 5800* flame, would have 
happened pretty briskly.
Maybe not.....dunno.........PF

John McPherson wrote:
> Forge welding is done by (comparatively slowly) bringing two separate 
> pieces just barely up to a welding heat over the complete surface to be 
> welded. This gives time for lots of scale formation, contamination, etc. 
> and the flux is there to prevent this, and gets squeezed out during the 
> actual welding of the two clean surfaces. Thin grease as a flux might 
> burn off during the heating cycle, using up the oxygen and leaving a 
> fairly clean surface, but the timing would be critical.
> 
> Electric or oxy/fuel welding is much like making new steel in a very 
> small, fast, mobile furnace. A clean weld can be stronger than the base 
> metal. Because you are using so much excess heat, you have to keep 
> moving or melt thru. This does not leave time to fully vaporize oil, 
> crud, paint, etc. so it gets mixed into the steel melt. Shielding gas or 
> flux is just there to prevent atmospheric contamination, and is no 
> substitute for clean metal. Clean metal + good filler rod + good 
> shielding + good technique add up to a good weld. Leave out one of those 
> and it may look OK, but....
> 
> Clear as mud?
> John McPherson
> 
>>
>>
>> This brings up yet another thing that leaves me even more confused...to
>> wit...
>> If one contaminates a torch or tig weld with oil or grease it gets ugly
>> usually....hard to get the weld to take......
>> Why isn't that the case with forge welding?....Pete F
>>
> 
> 
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