Copper block is the traditional backup for this application. I think
because it has a higher-enough melting temp than aluminium, which (if
hot enough to not suck the heat out of the joint) will be kinda soft.
HTH,
Donald.
> Date: Fri, 15 Mar 2002 09:25:04 -0800
> From: Barry Schwartz <bschwart@pacbell.net>
>
> Very soon I am will be into a project that will require I plug and refinish
> some holes in relatively thick sheet metal ( approx .10 thk) What does one
> use when welding (mig) to back up the hole? I was thinking of a large
> block of aluminum since the steel won't stick to it and it would have
> sufficient mass to prevent the metal from flowing out of the hole. This
> procedure would sure make it much easier to finish the surface off since I
> should only have to grind one side flat since theocratically the other side
> would already be flat since the backing plate would prevent any
> protrusions. Anybody already been there done that, got a better idea etc.?
>
> Barry Schwartz (San Diego) bschwart@pacbell.net
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