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Posted by Pete C. on January 5, 2008, 8:24 pm
Please log in for more thread options "Pete C." wrote:
>
> Ernie Leimkuhler wrote:
> >
> >
> > > Ernie, help :)
> > >
> > > I have a friend who wants me to weld up some holes on a Honda cast AL
> > > intake manifold. I haven't seen it yet, but I know welding on cast AL is
> > > tricky.
> > >
> > > I need advice on the best filler to use and the process. I believe I'll
> > > need to clean it well,
> >
> > Yep, got that right.
> > Including a die grinder with a burr to remove any contaminated surfaces.
> >
> > > bake it in an oven for some time to get oil out
> >
> > Then clean again.
>
> Any recommended solvents? I've got the usual assortment and can always
> get more.
>
> >
> > > of the pores, preheat it with O/A before welding
> >
> > yep, preheat helps a lot.
>
> What preheat temp should I be shooting for?
>
> >
> > >and then TIG it.
> >
> > So far so good.
> >
> > > Possibly clamp a piece of copper to the back side of the hole to provide
> > > support while filling.
> >
> > NOOOOOOO!
> >
> > Do NOT clamp a piece of copper to the backside EVER when welding
> > aluminum.
> > Aluminum and copper will alloy together to form aluminum bronze which is
> > extremely hard and brittle.
> > It is the same reason you never weld copper on an aluminum table.
> >
> > BAD THINGS HAPPEN!!!
>
> Noted, no copper near AL...
>
> >
> > >
> > > I've got O/A for the pre-heat, a Syncrowave 250 for the TIGing and an IR
> > > thermometer to check the pre-heat.
> > >
> > > Thanks,
> > >
> > > Pete C.
> >
> > The best filler for most aluminum castings is 4047.
> > It can be a bit tricky to find, but most suppliers can find it
> > eventually.
> >
> > I have stockpiled it whenever I find it.
> >
> > If no 4047 can be found, 4043 can work, but it is not as good.
>
> I have 4043 on hand. I'll check and see if I can find 4047.
>
> >
> > Expect to have to weld it more than once.
> > If the first weld is very dirty, with porosity (air bubbles), or
> > schmutz, then die grind it out and re-weld it.
> > An intake manifold is far cleaner than most other parts of an engine.
>
> That's what I'm hoping.
>
> >
> > When welding cast aluminum, you want to melt as little of the casting as
> > possible.
> > Just enough for the filler metal to bond with it, but not so much as to
> > alloy the filler into the base metal.
>
> Ok, any suggestion for amperage range I should be working in? Tungsten?
> Anything else?
>
> Thanks,
>
> Pete C.
While searching around for references to 4047 TIG filler, I ran across
this reference PDF which seems pretty useful:
http://www.afsa.org.za/publications/pocket-guide.pdf
Pete C.
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>
> I have a friend who wants me to weld up some holes on a Honda cast AL
> intake manifold. I haven't seen it yet, but I know welding on cast AL is
> tricky.
>
> I need advice on the best filler to use and the process. I believe I'll
> need to clean it well,