Which Filler rod for cast Alloy intake manifold

[Amit]

Hi Guys,

I have a cast alloy intake manifold which I want to cut, shorten and reweld.

I dont know exactly what its made of but am guessing an aluminium alloy?

Whats the best filler rod to use? Can I use a standard ally filler rod, or do I need something special?

If it helps, its from a VW 1.8 16v Engine

like this

Anyone in the ruislip area want to help?

I have a parweld ac/dc tig, but am a real begineer

 

[Paul.]

Use 4043 for cast aluminium , some here if you haven't already got some.
http://www.weldequip.com/4043-aluminium-tig-rods.htm

 

[pedrobedro]

4043 is usually used on cast items.

 

[scottmk1]

Will 5356 work ok when welding sheet aluminium to a cast alloy sump? or do I need to get some 4043?

 

[hotrodder]

It'll almost certainly physically work but it's very unlikely to be the best choice...
1st question would be what flavour is the ally sheet?
Ally castings are nearly always high in silicon as it 'helps' the casting process, that's why everyone recommended 4043. Another (less common) suspect is 4047 which is a higher silicon/lower temp (Eutectic point) alloy, which is better depends on the flavour of the casting which is virtually always unknown hence everyone usually reaching for 4043
The various different alloying elements used with ally all have a range in which they are crack sensitive and filler wire choice is usually made to keep the weld out of this sensitive area. There's various other properties that effect things too for example at the magnesium % present in 5356 weldments can end up susceptible to stress corrosion cracking if they see temps higher than ~65C

Amit, if you search the TIG forum for 'cast' you'll find a bunch of threads, the majority of them about ally. Cliff notes version is that castings are often 'dirty' to weld, the usual approach is clean, clean, clean, warm and see what happens. Keep a die grinder with a (preferably 'non-ferrous' cut) carbide burr to hand as the first attempt can often result in a load of black crud instead of a nice clean weldpool

There's a filler wire selection chart that covers things from various angles (ease of welding/strength/ductility etc) here... http://www.alcotec.com/us/en/support/Alloy-Selection-Chart.cfm and more indepth info for specific wires under 'alloy data sheets' although some of the wires mentioned are pretty rare/hard to get hold of

 

[quattro]

I started to re jig the manifold on my audi s2, the amount of dirt and black crud that came out of the weld pool mad it close as makes no difference impossible to weld, I made one from scratch in the end. Out of interest why are you shortening it?

 

[dannyp]

thats a bit of a rare manifold with the TB on the right, sirrocco 16v ???

id be tempted to practice on a golf KR manifold as they are plentyfull, they do weld but arnt the easyest to weld, done a few for myself with 4043 filler.

you'lll need acetone, stainless wire brush, snading disks for the angel grinder and i allways find a small die grinder usefull.

don't even bother trying to make the weld look pritty to begin with it won't happen, i usualy tack it up heavy then run a weld round, clen it up as a lot of crap will come out , if its really bad i'll run round the one edge then the other so not even attempt to weld them together but just use the weld to get the crap out the parent material, then clean it up again then weld them together. the finish will be rough , thats when i usally sand the weld down flat and lay yet another on top with the sole pourpose of looking pritty by this time all the crud thats going to rise up has doen and it's quite easy going as your basicly just puttign a bead ontop of filler wire