MIG'ing aluminum without gas?

What happens to the weld if someone MIG welds aluminum without using Argon of Argon gas mix?
The reason I ask is I have a set of aluminum exhaust manifolds on my boat. On one of them the water jacket cracked, while my son had the boat last winter and let if freeze with a little water in it. He removed it and had it welded. He said the guy used a "wire gun, that fed the aluminum wire as you welded". Questioning him farther made it clear the welder did use a MIG, but my son has no idea if he used gas or what kind of gas he used, if any. He doesn't remember seeing any gas bottles near the welder, and this was done at a home shop, where the guy does welding at night and on weekends.
The weld looks sh*ty. Not smooth and even. It doesn't leak, just looks like armature work.
I don't know if I should trust it, have it removed, and redone or what. I don't want to be 30 or 40 miles out in the Gulf stream and have problems with it, as this is on the main engine. I don't want to have to limp home using the trolling/emergency 40HP outboard, but I don't want to have to stand on my head to remove it from the 454 Chevy engine, which I would just about have to do.




Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Argon
If you are welding without gas, you are NOT MIG welding.
MIG stands for Metal Inert Gas.
There are aluminum electrodes for stick-welding machines, and i believe there is a flux-core aluminum wire for flux-core, gasless machines.
Bob Paulin - R.A.C.E. Race Car Chassis Analysis & Diel-in Services






Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Well thank you for your response, but you didn't tell me anything that I didn't know and you didn't answer my question. I know what MIG is. MIG is the common name for a process which is correctly known as GMAW (Gas Metal Arc Welding). When using flux cored wire the correct termonoligy is FCAW (Flux-Cored Arc Welding), which is done with or without gas. I am not aware of any flux-cored aluminum wire, which doesn't mean anything, as I don't know it all.
If you would read my post the very first sentence (which you copied in your reply) it will tell you what I am asking.
To go into more detail, I want to know the appearance, strenght, proisity, and characteristics of a weld made on aluminum with a MIG without using GAS, which I suspect was what happened in this case. I would like this knowledge so that I may make a judgement as to how this weld was done and the quality of this weld. In other words. Is it a good weld? Is it contaminated by something? Such as carbon from the exhaust, oil, etc.or is it just a bad weld? Is it strong?
Thank you, drive through!
--
Diamond Jim
"The Old Devil Dog"
  Click to see the full signature.





Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
i've never heard/seen of FCAW on aluminum either; but i do know the first step of inspection is visual. that being said, i would venture to say it (the weldment) doesn't pass your test...

aware
your
GAS,
knowledge
quality







Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Lots of aluminum oxide. I seriously doubt that weld was done with solid aluminum wire and no gas. Aluminum is enough of a prick without any help. Attempting to MIG it is asking for more problems. I also doubt that there is a FCAW wire for aluminum since it is almost too soft in solid form (to feed consistently) without making it into a tube.


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

it
you
but
like
just
In a nutshell...If you don't use gas you will gets LOTS of porosity!!!! You cannot mig weld alum without gas (we use Mison at work) It will never hold properly...I am surprised it doesn't leak too!!

work was being performed...especially if he was using a long push/pull style gun with an extended reach feeder...we have one called a Miller XR15A stands for extended reach, 15 foot, air cooled
Doobie










Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.