SEJW - Welding a Honda cast AL intake manifold advice needed...

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, bake it in an oven for some time to get oil out of the pores, preheat it with O/A before welding and then TIG it. Possibly clamp a piece of copper to the back side of the hole to provide support while filling.
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.
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Yep, got that right. Including a die grinder with a burr to remove any contaminated surfaces.

Then clean again.

yep, preheat helps a lot.

So far so good.

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!!!

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.
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.
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.
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Ernie Leimkuhler wrote:

Any recommended solvents? I've got the usual assortment and can always get more.

What preheat temp should I be shooting for?

Noted, no copper near AL...

I have 4043 on hand. I'll check and see if I can find 4047.

That's what I'm hoping.

Ok, any suggestion for amperage range I should be working in? Tungsten? Anything else?
Thanks,
    Pete C.
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"Pete C." wrote:

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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"Pete C." wrote:

Even better: http://www.afsa.org.za/welding-corner/welding-al-castings.pdf
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Another good one is from Lincoln
http://www.jflf.org/pdfs/wi299.pdf
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Carb cleaner and brake cleaner are both good. They are designed to evaporate and leave no residue.

At least 500 degF, but 600 to 700 is better.

Not without some info about thickness.

1/8" Lanthanated or even better, Zirconiated

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Ernie Leimkuhler wrote:

Good, I've got a few cans of some 3M brake parts cleaner on hand.

Ok.
I've only seen a picture of the manifold so far, but it looks like the holes are in raised bosses that are fairly thick, perhaps 3/4", while adjacent areas are probably around 1/4" thick.

Good, I have Lanthenated on hand.

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Ernie Leimkuhler wrote:

Do yourself a favour if you use these solvents, especially in a cool shop. Give the part a quick hit with a propane torch before welding. There is something in modern brake cleaners that remains on the surface and makes god awful fumes when you first strike an arc. A quick wave of the torch or a heat gun drives it off. Not sure what it is but it can be a real sinus burner......
Pete
--
Pete Snell
Department of Physics
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Pete Snell wrote:

Presumably whatever it is will go away during the preheat of the casting with the O/A torch prior to the TIG.
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Perhaps because it is a petroleum based product. I know for powder coating brake cleaner is a NOT recommend product because of residue, acetone is preferred.
Alex

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