I am building an intake manifold for a car and will be plugging holes (about 1" in diameter) on part of the original cast aluminum intake manifold I am retaining.

Is 6061 the best choice for aluminum to match with the cast?

Is ER4043 the correct filler rod to use?

I plan to use 1/8" thick 6061 to plug the holes with, weld beads all the way around, grind the beads down and smooth out the final product for polishing. The casting obviously is thicker in this area, especially since I'll be welding on a corner. Any tips on preventing burning through the thinner 1/8" plug?

Also with steel I can always go back and fill any areas I may burn through slightly with no problem. In my experience with aluminum I have been unable to fix these areas properly with the same technique. Does anyone have any clever ideas for fixing burn through areas when welding aluminum?

Thanks for any help!

 

I'm not certain on aluminum, but I know with sheet metal I typically use the stitch technique to work the hole from the outside in, so it creates it's own backing as I go. I can fill in a 3" hole with a MIG welder with ease on steel with no backing just by doing that, but I don't know how good it would hold vs. using a backing. You might end up with some porosity in the weld, which defeats the purpose of a good manifold.

As for aluminum, I hate it! I did some TIG welding with aluminum today at school and it pissed me offf

 

I did it... itll smell like *** when welding on the cast.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ExploitedRacing &raquo;</TD></TR><TR><TD CLASS="quote">I did it... itll smell like *** when welding on the cast.</TD></TR></TABLE>

Yup. lol

 

I believe I'm just going to try filling it in with filler metal. I'll post some pics how it goes. Thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Keyhole &raquo;</TD></TR><TR><TD CLASS="quote">I am building an intake manifold for a car and will be plugging holes (about 1" in diameter) on part of the original cast aluminum intake manifold I am retaining.

Is 6061 the best choice for aluminum to match with the cast?

</TD></TR></TABLE>

6061 works just fine for welding to cast aluminum. I've had a 1"x1"x7" block of it on the back of an aluminum volvo head for use in a hybrid engine and it did just fine.

 

you're going to want to use plugs if you have the abiltiy to turn some down to the appropriate diameter.