Cracked aluminum head

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A buddy wants this crack/break welded. Head is from a corvair motor, it fell from the cherry picker and cracked. I'll prep the  metal by cleaning and grooving the outside corner/edge. Do I need to weld the inside also? tig settings? cooling in sand when done? The head is off the engine and carbs are removed.  I have a tig welder that does aluminum, first time at doing something like this, any help here would be great...thanks !!! Attached Images
Reply:more pics... Attached Images
Reply:Do a search for member castweld posts on welding up aluminum heads.Peter typically recommends preheating to 350F, weld, heat, weld, heat, weld, repeat until done and then kill the heat and let cool down in oven for 30 minutes minimum.If you don't have an oven for the job you could use a propane BBQ/grill.What TIG do you have?  Going to need a fair amount of amps even with the preheat.Yes, weld inside and out (both vee'd) and probably use a pieces of flat bar to bolt to the gasket surface to keep everything true.Not sure what filler Peter would recommend but my guess is 5356.  ???MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:tig welder is a Lincoln 355 square wave monster
Reply:Then set if to the max and use the peddle as needed.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:You need to take EVERYTHING off it and remove it from the motor..Carb flange should not be that difficult but the more stripped you can get it the better.After that take a die grinder and bevel all the edges on both pieces as good as you can inside and out BUT leave a little of the original break material where it is for re-aligning...I would use 5356 filler and you will need all the heat you can get...You will need to go over the top where the gasket goes also because any crack left there will result in a vacuum leak and that's not acceptable..It's going to have to be re-surfaced one way or another for flatness..There are a number of ways to do this..all depends on what you have access to for tools/machinery...Sometimes you can get away with a disc grinder if you are REALLY good with it and sometimes you will need to set it up in a Bridgeport or equivelant type machine and fly cut the top..Either or DO IT RIGHT THE FIRST TIME OR ELSE!!!!!!!!!!...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:And by the way..It's not the head that needs attention..It's the intake manifold and it does unbolt from the head....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:What he saidDisclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:That one does not unbolt from the head. I've built many Corvairs and That is a real easy fix. Just do it right once. Mac
Reply:You will have the best results if you grind the edge of the brake mostly from the inside especially on the bottom.   Because its hard to get back in the hollow between the head and the manifold.  Mac
Reply:Corvairs came from the factory with aluminum heads?
Reply:If you don't have access to a mill to recut the mating surface you can do it by hand. Use a small angle grinder with a 2" to 3" roloc sanding disk, 36-50 grit will work fine. Take the weld down as much as possible without touching the flange surface. You  should be able to get it within a few thou or so. From there use a coarse honing stone or a steel sanding block with around 180 grit sand paper. Hone the flange surface until it has an even finish across the whole surface. Make sure to keep the honing block flat and don't let it rock.Lincoln precision TIG 275Millermatic 140 MIG
Reply:Got it done, I prepped everything real nice. Took out an old pc. of cast aluminum, ran one nice bead, and it came out great, so I'm thinkin GREAT this is going to be a breeze, but the next one--- make that 10, came out crappy. Took the head to my buddy who's been fixin stuff since the 70's and had him weld it up. Came out great. My cast aluminum tig skills are not ready for real world fixes!!! Practice on scrap is one thing and actual work is another. Plus, I didn't want to ruin my buddies corvair head, they are hard to come buy and it had machine/valve work done to it also. He was putting it the car to sell and they dropped the motor off the cherry picker and needed it welded asap to sell the car, so I figured I would play it safe and have it done right the first time. I watched my buddy threw the whole welding process and learned that cast aluminum welds like crap !!! The 2 side/flat areas came out great but the deep u groove part was a whole new story. He ended up grinding out some of the weld and re welding it, after that it came out nice. Maybe if I practiced tig welding on crappy dirty cast aluminum only, regular aluminum would be a breeze !!!