farm guys figured this out a long long time ago, no prep at all just lay it on the rust/paint/grease and it'll be fine as long as you say "that aint going nowhere" once it's done 😂

I tried it once many years ago and got similar results. What I think makes removing it between passes more important is proper placement of subsequent passes. It's hard to judge with all that crap in the way, imo.

I used to see farmers going over 6011 or 7011 without cleaning and the welds always held, they used to use the same rod to cut with outs in the field, crank a 5/32 rod to the highest amp the machine would go to and blow through what they needed to cut!

Better than I thought. Nice of you to cut and etch for us! Welds can look like turds? That NEVER happens! 😉

Nice video Greg. I’ve heard of old timers that claimed they could weld over slag and still produce clean welds. I’m sure it’s a struggle to actually burn through and still get the weld placement where you want it. I was pretty shocked with how clean the etch was. You’re one of the only ppl on here with this video subject. I tried looking this topic up just to see if the “hot pass” over slag ppl were blowin smoke, or if it could really be done

Thank you so much for showing this. I saw "IC weld" spotwelding like stacking dimes without cleaning. It was thin material and he made sure, to penetrate and not to burn through. I would never question this man, but i asked myself, why he was so confident. Now i know.

My dad taught me to weld and braze with ox/acetylene and with SMAW when I was eight years old. I never had clean metal to weld until I started TIG on aluminum 20 years later.

LH rod's no but crap conditions and 6011 you bet, lost track of how many times I had to sneak a rod sticking straight out, stinger, arm snaking in between other objects just to lay several beads on a repair job. surface prep/chipping ect. wasn't happening, even after air-arcing, gouge and weld. An X-ray would be interesting to see how much slag inclusion there was if any. cool experiment 👍🏻ty.

I'm always on standby until you put out another video:) Always improves me as a craftsman and welder. Thanks, man.

Thanks Greg. Always good info. Live n learn. Keep on tinkering.

As usual, best of the best! Many thanks!

Hi Greg, thanks for sharing this information......always great stuff

Worked much better than I expected!

Very InTeReStiNg. I wish I didn't know this years ago.. Cheers from So.Ca.USA 3rd House On the Left

That is neat to see. I have often thought the first pass flux would be melted by the second pass, but probably not a good thing to do. Thanks for trying and sharing.

Hmmm. Interesting. Good video.

Surprised by that result. The best way l have found for cleaning slag off a weld and in particular multi pass welds is with a needle scaler. The needle scaler also has a peining effect on the weld to stress relieve the material. You can see the tiny dents on the weld surface when you look closely at the shiny weld bead as you inspect it before the next pass. All interesting stuff young man!

I do surface build up and hard facing for equipment and weld over slag for years

It's one of those things that works sometimes - like when you're working on very small parts that stay at 800 degrees and doing an in position weld - and then people think it's perfectly fine everywhere because they've never had a problem since. Then a bridge almost collapses because someone left a massive slag inclusion inside a weld, and it gets fixed and everybody forgets about it and goes back to doing shoddy work. It's a good thing to test though, and I appreciate you saying it's a bad idea. Be neat to see you break it too.

interesting ! I've always heard that your supposed to clean and wire brush between passes but on the Ranch I had a brace brake on the bush hog and I was in a hurry.. so I welded up the brace without any prep at all welding through the paint and some rust the weld is strong to this day.... so I figured the weld would penetrate through the slag on top and that is exactly what it did , this is good to know ! clean it if you can... if you can't weld it anyway it will still hold if you watch the puddles close keep them connected and your going to be fine yes it's harder to see under that slag but it is do able !

So “Africa Style” welding isn’t so bad😂. Thanks and greetings from South Africa 🇿🇦

Very interesting test … I hardly every clean slag with multiple passes, and friends have always said it’s a no-no. They told me my welds wouldn’t be solid … but ur video shows it’s perfectly fine

Its common for us car audio guys to use welding cable when wtraight runs are all thats needed.

It depends on what you're running, like with fcaw-g you can stack flat wire without chipping your slag, until you start the next layer

Greetings, I have done it before Greg, so much until i understood how to make my tie ins perfect. The only difference is that i did it on horizontal, so the flux ran down on the bottom side of the previous bead, then i layed another on the upper end. Didn't have to fight against flux doing it like that. The right way is to clean the flux off though👍

I'm a bit of a lazy person, I like stick welding because I'll weld something down in a crevace where a mig gun won't fit, where I can't get a grinder in to clean up paint or rust or debris, and just burn it off and melt it in. I have left slag in place before (not an entire covering of slag, but bits where I couldn't get to it to knock it off,) and I always figured the weld was compromised, but at least it didn't break. Seeing this was surprising, as I didn't expect the amount of layer adhesion. I have welded over tacks without bothering to clean the slag off or feather them back without any adverse results, I think I even passed a couple bend tests doing that when I was in school and was even lazier than I am now. I like welding because it seems pretty forgiving, compared to woodworking or pottery. Steel is pretty strong, even a lousy weld done by a competent welder is usually strong enough to withstand whatever it is being used for. Most stuff I weld, the metal will bend well before the welds break.

My thought is that this seems like something that might be worth teaching to people where "fast & good-enough" (in that order) is the name of the game, like shipboard damage control teams where you might not have the time to do it right. Thought what might be even better is to formulate a flux that tends to "self remove" enough while cooling that just a swipe or two with a brush will clean most of it off. What might be more interesting would be a test with just doing a "lazy clean": a wack or two with a slag hammer and brush off whatever that knocks loose and call it ready for another bead.

use to use 6010 to start as being a hard place to clean then finish with 7018 over the 6010 slag, only because you couldn't clean it.

very surprised by the results

I work in wrought iron here in my town by the border! Here the new home builder's use cheap labor from across the river! I cannot tell you how bad it is but I can say that every job I've seen,this is exactly the type of welds you find in the field!

Spatter - blops! (What I called those little round things when working at Sunkist. I needed to clean them off pattern-packer frames to get them ready for painting.)

Hey Greg, thanks for another excellent video! My welding instructor claimed that it is possible to "burn through" or "burn out" slag with basic electrodes but not so much with rutile electrodes. I have nowhere near enough experience to judge whether he's right or not, but it may be worth taking into consideration.

I have had to do this a time or two, but I prefer proper prep and flux removal between beads. However, the times I did do this, it has not failed, and I suspect it never will.

That looks totally fine. This is what flux is for. It's just doing its job.

Yes, you can stick weld over "some" slag. They just don't want you to know. There is a Pro Pipe Welder on KZfaq who welds over "some" slag all the time with 100% X-Ray required of every weld he makes.

The red weld cable is flex welding lead

Always buy the best cables. Not a welder, but I buy marine grade everything for solar.

I’ve done that same thing before when I’m welding on something not structural. It works pretty good actually. I use a needle scaler on the slag

Im thinking how many cleaninbetween when filling holes or large gaps. Your weld looked great

wow thats some chunk of steel you have for your table! how thick is it an how did you get that?

To slang off or not to slag off. That is the question

I have done welding over slag but its not an overly structural thing when I do it. Most the times I use Mig with flux core so the slag on top is quite thin so it works well enough. I have found going a bit slow at the start and giving a bit extra will get enough heat to allow the top layer to burn off or reflow. But again its not structural welding and more fill welding. Its a very situational use type thing and not an all the time.

I’ve bee forced to weld some really rusty steel at times. I don’t like it, but it is what it is. I crank up the heat high enough to burn through the rust, and go a bit slower I must have done something right, because I’ve not had a failure.

Best tool to clean up flux is spring loaded center punch, the one with the big plastic ball on the end...

LOL I'm a retired Boilermaker, we used to slag weld tubes all the time

🤔 Well, slag is actually an integral part of wrought iron. 🤷 might be somewhat OK. It is an electric insulator though. I can’t see that as good thing.

Why have I been wasting all this time cleaning the slag off. I'm going to start welding this way. Thank You!

6013 makes the worst slag in my opinion. I tried welding over 6013 slag and got too much porosity. That porosity would remain even if a big enough charge gives the electrode more penetration over sticky 6013 slag.

Holy s***! 200 amps arcing to the table! That would have been a change of pants for sure. Do not pass go. Do not collect $200.

Hoping for what is likely impossible, but I hope you get the camera back someday

Austin Ross did a vid on it a while ago.

I think the reason for cleaning is different than I would have thought.

Mentioning cables. I normally buy Excelene welding cable in 2 gauge. Last week I bought two lengths of it in 20 feet each. One red and one black. When it came in all it says on the cable are numbers every foot, or so indicating how many feet on the roll it was cut from. I sent a message to the supplier, one I’ve been using for several years about this, but haven’t received a reply yet. To say this is disturbing would be mild. I have no idea who makes these cables, or where they’re made. I’m hesitant to make anything from them. They weren’t cheap either, $115 for the total of 40 feet without shipping or tax.

Slag floors that’s why this works ok.

I used to f around in welding class and do this and my bevel bend tests would fail miserably

If you weld over slag you gonna have slag trapped inside your weld fillet and its not recommended :)

Camera got stolen?

Only time I did anything like this was plug welding holes.

Can you do the same video please with 7018

I used to do that all the time had pretty good results not saying it's right

I hope whoever stole your camera can never find the cool side of a pillow or trust a fart ever again.

Is this guy ToTs older brother? 🤔

What do you mean? That's the right way to do it, your SUPPOSED to weld over the slag! ... 😂

what a miserable thing to put yourself through! LOL

You can test for cracks maybe show something

I hope my dad never sees this video because he yells at me for taking the time to clean my projects before welding them and he would never even imagine grinding the paint off. He has been stick welding since that was high tech so he can or will not change his mind and I have watched him weld over slag countless times and even paint over the slag when he is finished arguing that it is just more protection for the weld. If he sees this video he will surely take it as confirmation that his way is the best, but luckily since I am old he is ancient and has a hard time figuring out how to use a remote so I feel pretty safe keeping the secret. Lol

I thought it was gonna end up like cutting into a cake, totally wrong.

Undercut comes from, 1. Arc length too long 2.Travel speed too fast. your ripple shape should be like the curve of a crescent moon not arrowshaped. 3. Amperage too high 4.angle on last pass too high. I taught welders to pass the Codes.I have been in the trade since 1967. Also the top pass should be allowed to cover 2/3rds of the bottom to avoid a mini valley between the two. Over all the weld is reasonable but can be improved to be spot on.

brother, Ive been test welding, and my welds are dog shit

I've seen guys pass CWB tests doing this shit.

I'd argue that not cleaning after each pass saves you about 20 seconds per pass of clean-up time. That's 60 seconds. That's 60 seconds you could spend having sex with someone. So, you know, make up your own mind. Or a nice cup of tea.

Weld over slag? You mean that you're supposed to take it off. 😣

I expected decent results, but not this good.

Great video! Supports the 7018 claim: "Its efficacy on rusty or painted metals makes it a practical option for field repairs, reducing the need for extensive surface preparation" ... (americanindustrialsupl)

Why would anyone waste their time doing this? I'm sorry I wasted my time