How do I weld up a sump without making it look like crap?

[RAd28]

I haven't tried exhaust pipe yet, but I can't imagine it being all that easy... i've done some small OD thick wall pipe, and it's a bitch because you just can't get a long enough bead with out stop starting... and that's where things go wrong for me...

[RAd28]

Here's a question for the welding nerds... why do welding magnets repel the molten welding metal??? i noticed when I was doing my spot weld right next to the magnets, it would just spray the metal away (kinda like welding with no gas)... At first I couldn't figure out why it was doing it, later I realised it was the magnets doing it, but I was thinking about it today, and magnets are suppose to ATTRACT metal like that... So I figured it must be the current flowing through molten metal that creates an opposite magnetic field...

any one able to provide a explaination?

[auto351]

I have been using Co2 as a shielding gas for year and it works well with my SIP, I have found using Co2 reduces the effective current output of the unit giving lower setting that would other wise be available.
I find welding with Co2 give me better results that Argon (most likely as I have been using it for so long) , the only problem is it tends to produce more splatter.

[essaysixtythree]

I haven't tried exhaust pipe yet, but I can't imagine it being all that easy... i've done some small OD thick wall pipe, and it's a bitch because you just can't get a long enough bead with out stop starting... and that's where things go wrong for me...

Yeah its a bit stop start gotta keep changing angle and turning the workpiece over. Some of my joins had gaps I had to fill to start with too which made it a bit more difficult. Just turn the heat and speed down.

I may have to do my sump too. Rwd 3s but iv just put the baffles in there with some hardcore epoxy at the present. See how long that last and if the motor starves

[marc280]

Hey RAd28, good to see that the welds are improving. Looking at the pics it seems you had the spots looking good at about photo 6. In the second photo where there is a weld bead run along beside the spots, how does it look on the other side? I'm guessing you were doing this on the lowest voltage setting? If the settings seem to be working well, my suggestion would be to just lay down some beads in the middle of the practice piece and try to find a good travel speed where you get a nice consistent weld profile. Once you've got consistent width and penetration working well then move to the butt weld.

Like roadkill was saying, brass is a good heat sink and is what I've always used when welding thin stainless stuff, so if you can get a piece it would also likely help in preventing blowing through like you've been finding.

For the magnetism my guess would be that by having the current flowing in a magnetic field you are getting an electromagnetic force moving the weld metal (similarly to and electric motor where you have a current flowing through the windings in a magnetic field to create a force) maybe?......

CO2 can be good for welding mild steel especially for thicker sections as it does give deeper penetration like auto351 was saying. If I remember right, using CO2 changes the trasfer mode of the weld metal to a 'globular transfer' which gives the deeper penetration and a narrower weld bead profile when compared to argon mixes. Then you can use a Helium/CO2 mix if you are looking for a cleaner weld with good penetration and a wider profile.

[RAd28]

marc280 - That bead i've got running off away from the seam I just did as a test run, i can't remember now whether I did it on voltage setting 1 or 2... but there was WAY too much penetration, it looks almost the same from the other side... trying to do a decent bead like that on the edge of the plate like a butt weld just blew big holes...

[JZA70R_92]

I welded up my sump on my falcon using my oxy. size 6 tip and low settings on oxy/acy get it to nutral flame and get it so it just melts a puddle in the steel then slowy weld it up! I also use it do body repairs...oxy hammer welding FTW if you do it correctly and have a very paper thin gap you can fusion weld the steel. make sure to use a hammer and dolly to strecth the metel back and a wet cloth.......