[TheForge] welding heat

Thu Jul 31 20:31:00 2003

Hey Folks,
At the risk of incurring the wrath of the fluxless weld crowd again,
I find it a big help to use my Didymium/gold face shield when forge welding.
Didymium doesn't filter UVA and UVB or IR.
It is effective only for filtering out sodium (Yellow) flair, caused by the
borax flux: But the Gold filters out everything else without darkening your
whole field of vision.
When making damascus, since it filters the IR, you can see any dark shadows
that indicate weld flaws, and you can really see the flux dancing on the
billet when you reach welding temperature. It is Like having x-ray vision.
The gold blocks the IR so effectively that you can stick your face way too
close to the forge and not feel any heat behind the shield. Of course at
this point any unprotected areas of your body will be reaching flash point.
The only other cautions I have are, that there is a color shift in the color
temperatures you have to get used to, and the gold surface of the shield is
fragile.
One other point, the forge welding temperature is inversely proportional to
the carbon content of the steel in simple carbon steels.
The higher the carbon content the lower the welding temperature.
Chuck

----- Original Message -----
From: "Jerry Frost" <[email protected]>
To: <[email protected]>
Sent: Thursday, July 31, 2003 4:57 PM
Subject: Re: [TheForge] welding heat

>
> >
> > It really surprised me the first time I did this, but....
> > After watching Fiorini's demo and playing around with this, I've found
> that
> > I can often weld at a bright orange. The probe sticks, and as long as
it's
> > soaked and clean, it welds.
> > Yeah, I know, totally contrary to THE WAY IT IS DONE, but it works for
me.
> > Andy. G.
> >
>
> Judging the heat in bright light can be difficult but it only takes
> practice. I've been working outdoors so long (my tarp tent is not much
> better) I have more trouble judging temps in dim light. I'm afraid the
> couple people I've shown smithing will have the same problem, for a while
> anyway. <grin> This isn't a bad thing as I and my students judge temp by
> sound and feel as well as color. Sound and feel do not change in varying
> light conditions. A quick withdrawl from the forge for a light tap in the
> anvil is enough to tell me if it's ready to weld.
>
> I've found that in my rich running prop. forge, I can easily weld at
> med-high orange and up.
>
> When I showed Lindsey how to weld I hedged the bet and had her clean the
> scarfs with emery cloth and close it up cold. Being only 3/8" stock it
> didn't take much soaking. I like to flux as soon as the steel shows color
to
> minimize oxidation even though my propane forge runs pretty rich and you
can
> weld without flux if the scarfs are clean enough.
>
> Judging welding heat in my prop forge is basically a matter of setting the
> regulator. To "help" students judge temp I sometimes end up cranking up
the
> prop. to around 8-9 psi. At this psi. my little forge will have steel
> dripping off a 3/8" bar in about 3 minutes. It really helps instruct a new
> student to keep an eye on the fire AND listen to me. <evil grin>
>
> Working in a "real" fire I look for both the wet and watery / flickery
> /swirly / etc. surface effect. The "wet sheen" look tells me the surface
is
> to temp but it's different from the flickery/watery look. This effect only
> really happens when the stock is soaked to depth, maybe not through and
> through but plenty deep enough to weld. Flickery and watery are only
> descriptive words, Ralph mentioned colors and swirls this is as good a
> description as any. Basically there are subtle color differences
flickering
> in the steel like watching colored flames dancing across a log.
>
> There's another temp I look for the flickering colors and that's critical
> temp for heat treating. Though it's a different temp the steel gives a
> similar cue.
>
> I love steel, once you learn to speak it's language it tells you all you
> need to know in plain steelish.
>
> Frosty
> ------------------------
> If it ain't forged
> it ain't real.
> Wrought iron is.
> The FrostWorks
>
> Meadow Lakes, AK.
>
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