Welding aluminum and magnesium castings is similar to fishing in the ocean, one never quite knows what one might hook up with. The *eruptions* sound nasty and your guess about oil sounds best. But what can you do with a temperamental casting beside route out the bad metal and try to fillweld?
Once upon a time, back in the days of old when we we were gleefully killing the Ozone. There was a miraculous (yet evil) thing called a *Vapor degreaser* this device would contain <or try to contain> a heated mist of Trichloroethane. The heated vapor would expand the part (expanding the flaws) allowing the magical mist to find its way into every nook and cranny- making pure what was once sullied by grease or oil. Now we have soap and water. Do I sound bitter?
I have heard of folks preheating the part to burn away the oils and stuff prior to welding but that sounds risky and would most likely run you afoul if your work requires the material to be near its original temper designation.
Long live the Green Knight! Slayer of Vapor Degreasers, and Long live the Butterflies the Snaildarters and the Earthfriends!
we will find solutions despite their *help*
Thinking green thoughts
Lar
Colorado,
We are currently welding a die cast 360, currently using Alcotec 4145
filler rod. Prior to welding we use a orbital grinder with a 40 grit disc and
clean the are to be welded ( make sure the disc is only being used on the aluminum ), also sandblasting the area is an option.
I have talked to Tony Anderson at Alcotec and they recommend using
Tri-Clean that is made by LPS ( lubricant manufacturer ) to clean the castings before welding, you can get at most industrial supply houses.
Keeping an eye on your amperage is critical,if you put to much heat into
the casting all of the impurities come up out of the castings. We requested the people that do our casting run our parts through a
vibratory cleaning before being sent to us.
By doing the following we have had good sucess in the welds, as a
side note we pressure test the welds since they have to be airtight.
Good luck Brett B