weld rusty metal

[LittleBill21]

I welded some really sad rusty cr@ap farm item a couple days ago--do it all the time-- and used Lincoln flux core wire. The weld penetrated well and looked surprisingly good. It's not going anywhere.

I know conventional wisdom around here is to wire brush and grind everything to clean metal--and that's true for MIG but I have not done that with rusty metal and flux core wire and don't think you need to. Read the welding section here for more. Some of those guys are world class welders and have good things to say about rusty metal and flux core wire (or stick). Wire feed is just easier and looks better in my view.

i just bought a roll of flux core wire, i was allways told to just use gas, but looking at my welder it appears it can welder hotter with the flux core. i will try the rusty steel with it, i will say it smokes crazy hard compared to gas, i actually have to clean my welding mask from it

 

[LittleBill21]

I've welded thousands of feet of rusty pipe for fencing. After 15 years the pipe may rust apart, but the weld holds. I use 6010+, and never clean the rust. It is a fast freeze rod and does fine.

what does the "+" gain you?

 

[joefromga]

what does the "+" gain you?

"It goes to eleven. "

 

[Gary Fowler]

Just because a rod MAY weld two pieces of rusty metal together does not mean that you should do it. Rust is oxidized metal and heating it produces oxygen in the weld metal AND that is not good especially on thinner metal like an exhaust pipe. The thin metal is not going to be easy to weld without burning thru when clean and will become extremely hard to weld (and hold together) when welding over dirt and rust.
With the proper tools and a little time, just about any part in any position can be cleaned. If you can get a welding rod in to weld it, you can get 100 grit emery cloth to clean it or a file at minimum. You will actually save time by cleaning it as best you can before striking an arc than trying to patch holes and fight the rust and weld metal falling off.

Just like the old saying "Pay me now or pay me later", the same goes for cleaning metal before welding. You can spend time grinding off the rust or spend more time grinding off the dingle berries, porosity and slag, and filling in burn thru holes.
If beginning welders would thoroughly clean the metal before trying to lay a bead, their welds would show a 1000% improvement over stuff welded on dirty, rusty material.

 

[SPYDERLK]

I've been struggling with repairing a trailer with 6011 and it's really bad rusty. It's so difficult that I'm beginning to wonder of I have bad rods. I have both 1/8 and 3/32 and the welds are horrible. It's not too bad on clean metals but rust is just not a good thing for welding.

Use 3/32 and pretty High Amp. Weld ~ 1/4" at a time. Stop - start to keep from blowing thru. Once you have metal laying down restarts will be easy.

 

[joefromga]

Use 3/32 and pretty High Amp. Weld ~ 1/4" at a time. Stop - start to keep from blowing thru. Once you have metal laying down restarts will be easy.

Thanks. I've been having trouble with not being able to get any arc length even 1/8th" or it cuts out. It easily restarts and I can tap and keep it going but I basically have to drag the rod and tap to keep it going. I'm going to try to remove more rust when I get back to it.

Learning is fun.

 

[D2Cat]

DC vs. AC Polarity for SMAW

6010 vs. 6010 +++++? [Archive] - Weld Talk Message Boards

 

[jenkinsph]

Just because a rod MAY weld two pieces of rusty metal together does not mean that you should do it. Rust is oxidized metal and heating it produces oxygen in the weld metal AND that is not good especially on thinner metal like an exhaust pipe. The thin metal is not going to be easy to weld without burning thru when clean and will become extremely hard to weld (and hold together) when welding over dirt and rust.
With the proper tools and a little time, just about any part in any position can be cleaned. If you can get a welding rod in to weld it, you can get 100 grit emery cloth to clean it or a file at minimum. You will actually save time by cleaning it as best you can before striking an arc than trying to patch holes and fight the rust and weld metal falling off.

Just like the old saying "Pay me now or pay me later", the same goes for cleaning metal before welding. You can spend time grinding off the rust or spend more time grinding off the dingle berries, porosity and slag, and filling in burn thru holes.
If beginning welders would thoroughly clean the metal before trying to lay a bead, their welds would show a 1000% improvement over stuff welded on dirty, rusty material.

I agree with this^^^
Clean it as best you can before starting to weld. I am not a welder imo but I do clean everything first and so far it sticks together without problems.

 

[Deezl Smoke]

Any welder with experience will have had to weld into places that can not be cleaned well as the OP mentions. You can clean as far as you can, but often there will those little spots on top of an exhaust tube, in some spot that can not be easily removed for cleaning. This makes welding a real head scratcher at times. I say head scratcher as I have already pulled all my hair out trying to weld those uncleaned spots. So scratching is all that's left.

Problem is, you set the welder for the clean area, then hit the rust. This is where issues will come up. Learn to set your welder. Weld as much clean as you can, then re set your welder and go to the rusty spots. But in general, if you can weld it, you can do some form of cleaning. Be it an emery tape, or a wire brush, as much cleaning as you can do will always end up benefiting the weld and the job time.

When I was young, I was an impatient sort that could'nt see 3 seconds in front of me. It always came back to haunt me in about every thing I did. Welding was the top of the list. Eventually it was shown to me how much quicker it was to "invest" some time before striking an arc in preparation. Sure enough, now I take the time to prepare the joint as best I can, and the welding not only goes faster, but I dont have to redo it later or chase leaks and cracks.

 

[lamanated]

I have a pistol type sandblaster, to clean small spots up, prior,, great tool and cheap