replying to clare , Bob Lowe wrote:
clare wrote:

On Thu, 13 Feb 2014 09:34:59 +0700, John B.
No orange flair, for one.
Cobalt Gold - not cobalt actually (better for the eyes) - or better
yet the TM2000 from Tinmantech.com. They are an emerald green. And
expensive.
The Cobalt lens is not effective against ultraviolet, so if you are
doing a lot of welding the TinMan lens is worth while (won't give you
cataracts)


Hi - I just copied this from a Hobart Welding Guide.

"Aluminum does not exhibit color as it approaches its melting temperature.
Aluminum will show color above the melting point, at which time it will
glow a dull red.

When soldering or brazing aluminum with a torch, flux is used and the flux
will melt at the temperature of the base metal approaches the temperature
required. The flux first dries out and then melts as the base metal
reaches the correct working temperature.

When torch welding with oxyacetylene or oxy-hydrogen the surface of the
flux will melt first and assume a characteristic wet and shiny appearance.
(This aids in knowing when welding temperatures are reached.)

When welding with gas tungsten arc or gas metal arc, color is not too
important because the weld is quickly completed before the adjoining area
would melt.

When the factors above are taken into consideration it will allow making
welded joints in aluminum with little or no more trouble than when welding
steels."

I assume that this may be correct but maybe an over simplification of
things. I notice how it jumps from start to finish in 5 short paragraphs
with (...no more trouble than welding steels).

Based on other things that I have read, rather than just relying on this
'wet and shiny appearance', with certain types of goggle lens and
different fluxes a color change can help judge this ideal temperature
range more easily, (before it falls on the floor). Is this a fair
assessment? If this can be accepted then it appears to me that the idea
of lens types and fluxes can be a 'fast-track' to the better aluminum weld
with a standard oxyacetylene welder. Do you aluminum welders out there
agree with this? If so, it sounds like maybe one can make this a big step
in getting that better aluminum weld more sooner than later without the
investment of an expensive welder for the casual odd job aluminum welding.

Bob Lowe

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