[subwayrocket]

I've been doing some welding on a F450 flatbed lumber deliver dump truck with my buddy . The guy he bought it from added to the upright section that is directly behind the cab . Everywhere else on the dump body welded very nice, I had him prep everything to shiny bright metal at least a half inch beyond any weld joints . One piece of 1/4" angle iron the guy added was hell to weld . As soon as I would initiate an arc, it would flash, sizzle, boil out yellow and become porous, much like very crappy cast aluminum . Just like when you light a match. If I tried to add filler, it would start to take but often pop and blow out the weld, leaving either a 1/32" or 1/16" porosity hole or blow out leaving a very shallow crater surrounded by yellow and or white smoke. It smelled strongly like doritos or garlic .

Anyone have an idea what I was dealing with here ?

Since it acted like crappy cast aluminum, I decided i'd treat it similarly. With pedal pumping, I would go a few inches (no filler) just boiling out the impurities. Then wire brush it and "tin" the area fusing in good metal (er70s6) . This seemed to work. So then I decided to try "tinning" it with the 625 filler I have. This seemed to resolve it. Then I was able to wiggle the cup all the way down this joint with er70 . The original owner had a mig bead on this piece of angle and the whole bead was cracked right where the bead edge went in it. I'm hoping that by boiling out the "crap" and tinning in good metal that this wont happen again. . . . not sure if i'm using the word "tinning" correctly .

Again, if anyone has ever dealt with something like this, share your experience. I appreciate it, and thanks in advance !
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This dump is for construction demolition, wood, shingles, etc ...not loads of fill or tons of rock.
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DumpBodySides.jpg (45.8 KiB) Viewed 1115 times

[AFR_Autoworks]

Sounds like you are trying to weld galvanized steel. Try grinding the material down further and see if it helps. The only way I have ever had luck welding galvanized is taking the material down past the coating. If you use a flap disc you will clearly see when you break through. Make sure you do the same with the backside as well. Also, are you welding outdoors? Slight drafts can really mess with you while Tig welding.

[subwayrocket]

Sounds like you are trying to weld galvanized steel. Try grinding the material down further and see if it helps. Also, are you welding outdoors? Slight drafts can really mess with you while Tig welding.

I was thinking that it might be galv , but it had a slight rust coating when we sanded thru the paint so then I wasn't sure . We flap disc'd it with 36 grit real good . I went back and skimmed the entire joint with a cutoff wheel held at an angle. We were definitely thru if there was any coating there . Thanks !

[AFR_Autoworks]

If it was already welded there is a good chance you are pulling the zinc into the weld from the backside of the angle iron. Galvanized is some nasty stuff. Once the zinc reaches a certain temp it seems to pop and your puddle explodes.

[AFR_Autoworks]

If it is not too much trouble you may be further ahead cutting the whole piece off and starting over.

[subwayrocket]

There was no welding done where I had to weld. Just the one spot where I examined all the previous mig welds and found that 2" bead , no where close to where I was welding. This piece is integrated into the whole front of the thing or I would have cut it out . I will try to get a few pics of it soon . We were calling it "Pig iron" ...haha ... great Johnny Cash song btw ...Rock island line
Thanks man !

[AFR_Autoworks]

I am sorry I could not be of more assistance. If you are forced to weld it, just run a bunch of small welds and let the material stay cool.

[Poland308]

If it is some sort of galv. And your description sounds like it is then burning through or grinding down is your only option. The galv process is like a deep etching it really is embedded into the pores of the metal. Trying to tig over an existing mig weld will give almost the same problems. Try to burn through it if you can't grind. Be ready to change tungstens often. It's messy and grind out as much as you can along the way.

[subwayrocket]

Trying to tig over an existing mig weld will give almost the same problems. Try to burn through it if you can't grind. Be ready to change tungstens often. It's messy and grind out as much as you can along the way.

Thanks much AFR , your input helps shed some light on what I've got. The weird thing is I never felt or got sick from welding it...and it had also some surface rust .

Poland , that's exactly what I ended up doing. Do you think this is ok , what I wrote in my original post ?
And I cut out that bad mig weld with a cutoff wheel .
Thanks much !

[Poland308]

If your carefull and outside and keep your head out of the fumes you will be ok. Galv poisoning is something you get more sensitive to the more you are exposed to. I've welded on lots of galv and never gotten sick. But I've seen people who have gotten sick from it. It doesn't look like fun.

[motox]

drink a big glass of milk before you weld it
craig

[subwayrocket]

drink a big glass of milk before you weld it
craig

we never felt sick . Felt great the next day . idk

[big gear head]

Could it have been cast iron? Maybe it was something other than mild steel.

[xryan]

Galvanized. Grind the crap off, wear a HEPA mask (P100/N100) and weld it outside. Or better yet, let your buddy weld it.