[TheForge] Welding cast wood stove baffle

Mon Apr 8 22:08:00 2002

        Michael, thanks for the graphite info, never had heard that.  I use
heavy 5/8 copper plates to back welds from falling thru on plug welds, anvil
corners, etc.  That would work for the cast too I would think.
        I don't think I'd go to dull red with a preheat.  If lincoln advises
it with the graphite problem that's fine - they know wha they are up to.
        The reason I'd go to 400-600 degrees is the maximum rate of
expansion is around 900 somewheres...........so if you go to 4-600 you get
to add some heat while welding, it cools some while you peen, then add more
heat, etc.  If you take it beyond maximum expansion when some parts cool
faster than others you'd have some serious tensions created in the piece.
        Just my two cents, I could be wrong (again - it wouldn't surprise
me). The more I learn, the more ignorant I feel.

Ralph


----- Original Message -----
From: "Michael Boettcher" <[email protected]>
To: <[email protected]>
Sent: Monday, April 08, 2002 9:26 PM
Subject: Re: [TheForge] Welding cast wood stove baffle


> At 08:42 PM 4/8/2002 -0400, you wrote:
> ><excellent advice snipped>
> >Ralph
> The part is cast iron.  During stop drilling, the chips (powder actually)
> was black.  I'm used to seeing a dark grey, but not BLACK. The first 1/64
> to 1/32" was really black as well.  We ended up brazing it.
>
> After doing a bit of research, and talking with people, I found the Lincon
> "The Procedure Handbook of Arc Welding."  In it they said:
>
> Castings with High-Graphite Content:  Castings having a great amount of
> large, free graphite flakes are difficult to weld, since the weld metal
> does not fuse to graphite.  Instead, it tends to ball-up and resists
> working into the melted surface of the casting.  This behavior is most
> common on castings that have been heated repeatedly, such as old furnace
> grates or exhaust manifolds.  The ESt electrodes for cast iron have a
> coating designed to flux out some of this flaky graphite, thereby
improving
> fusion.
>
> The balling up of the weld material was really evident when I tried to
weld
> it.  So...  I guess the answer is to get a cast iron rod, preheat the
> entire thing up to almost dull red, and weld away.  Hmmm... with the way
> the welding went, I think it needs to be in a bed of sand to support the
> molten burn-thru.
>
> Thanks everyone for your advice.
>
> Michael
> Madison, WI
>
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