Welding Tips and Tricks

Guys,
I'm new to this forum and have seen many vids on TIGing cast aluminum. I have the usual soot issues with plenty of pores. Despite this I have no problems making an OK weld. My problem is that this piece is an engine intake manifold for a turbo charged car and when I pressure test it, it leaks like a sieve and I'm sure it will have a vacuum leak as well.
Anybody have any tricks for eliminating this problem?
I am not new to aluminum, I've made radiators, intercoolers, intercooler tubing, intake manifolds (from scratch) and none of those leak (because they are new clean aluminum), but this thing is old and oil soaked.
Many thanks
James

Just how oily is it? You did remove it from the vehicle and give it a nice super heated bath with degreaser, right?

I usually boil my aluminum engine components in a wash tub.
With enough water to totally submerse the parts I add a box
of washing soda and a bottle of Eagle 1 aluminum wheel cleaner.
It gets boiled for about an hour. Then from the bottom of the tub
I slowly flood it with fresh water. The gunk just floats over the top.
Dry, wipe with acetone, wire brush and wipe with acetone again.
It usually welds a lot better after a real good cleaning.

I often weld cast, and when I come across similar situations, I either will have to weld it, grind that weld down again and reweld it. Either way, you can still end up chasing porosity. I find it best that whenever I can, it is just best to weld a coupon of 11 gauge over the repair area. Even if it means having to anneal it and shape/form it to fit.

Here is a problem with severe salt inclusion. By the time I got this to seal with a weld, it would look awful and likely be 10 times the size it started out as. I know it's not cast, but it may as well be by the time salt finds it's way through it.


No ugly dirty weld, and no leaks.


The 5052 we get can be further annealed to an almost putty like state with a mapp torch with such small pieces. You can then tack one side and either hammer, or clamp form it to fit even complicated shapes.

tamjeff
what rod do you use for patches like the one above?
thanks
craig

motox wrote:tamjeff
what rod do you use for patches like the one above?
thanks
craig

5356. It's what I usually have the most of anyway.

I didn't put a lot of love into it but the weld is sound.

Many people don't think to repair cast like that but it is often one of the best ways. Minimal distortion an less chance of cracking and not to mention the additional support. I once repaired a transmission (threw a U-joint/drive shaft) case where the poor guy who tried to weld it before me had only made it way worse. By the time it got to me, the owner had nothing to lose so he let me have at it any way I saw fit. I made a perfect saddle patch for it, radius'd all the corners, welded it up nice and the owner thought it looked cool. Even if you can weld the cracks up decently, it's still a good fail safe on mechanically critical parts.