Rusty cold joint repair?

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It was dark last night when i got done, so i didn't get a pic.on my usual walk around after use, i found a broken weld on my snowplow -- no big surprise.The problem is that it is in a location where i can't get a grinder to it.To me it looks like the original weld was too cold and finally "popped" ... or about half of it did, anyway.how do you fix a rusty old cold joint you can't grind out?all i have is an AC arc welder.  ive thought about trying to cut it out with a cutting rod, but ive never done that before. OR .. just go over it with some 6011 for now and hope it makes it till spring.  thoughts?Ill try to get some pics here today....Mike
Reply:Can you use a die grinder with a long burr head like is used when porting heads? Attached ImagesMillermatic 200Hobart Handler 120Victor O/A & Ramco BandsawLincoln 225 ACSnapOn AD HoodMiller XMT304/22AHypertherm Powermax 1650 G3Lincoln Idealarc DC600 w/Extreme 12 VSMiller Digital Elite "Joker"
Reply:Needle gun, sand blaster, wire wheel or brush? I think we need a pic.  In some very tight spots I have used as little as a screw driver to scrape away some junk before welding.
Reply:How about an oxyfuel torch?
Reply:6011 on the buzz box and burn it in hot, nothing over 1/4" on most pickup sized plows. Throw a plate over it or make a gusset to stiffen it up. Seriously how deep do you want to go on an old snowplow.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:Here's the overall layout of the joint.  The weld in question doesn't see much load except with the blade is lifted.  I was pushing into some piles with the blade up trying to stack the snow up a bit, so i'm thinking that is why the weld finally showed it's weakness.another pic showing the layout ... the weld i question is the fillet weld on top of the tabs for the plow pinsHere's a closeup showing where the weld has failed.  this is why i say it looks like a cold weld from day one:Another showing the weld failure.TozziWelding makes an excellent point with how far to go with it.  I guess my answer would be "far enough to keep using it, and not much else"given the opportunity and skills, i'd re-do the whole thing, but i don't see that happening.  If i can fix on it here and there every year to keep it going, i'll be happy.  Maybe in a few years i can upgrade, but for now, i'm just tickled to death not to be driving the tractor/loader out in the cold.I do have a die grinder, but no bits small enough to get into the corner to grind it out.  I'd just weld over the top, but i know welding over cracks is bad Ju-Ju.  Not sure if this is really a crack, or just a lack of fusion.unfortunately, the whole plow is built with welds like this.  but it has held up pretty well for being a nearly 30 year old plow.on the plus side, my previous repairs have held up beautifully. They aren't real pretty, but worlds ahead of the "repairs" that were done with what looked like a 110v welder.... so i'm feeling pretty good about that.  Nothing to brag about, but they are all holding up well, gosh-darnit seeing the pics, what do you guys think?  Light up and light out, or try to grind it out before re-welding?Last edited by Meborder; 12-24-2012 at 09:13 PM.
Reply:I'm the Tozzi, 6011 and burn it in.
Reply:If you have the power you should be able to weld that clear to the bottom of the crack with 6011 . Its all solid Iron .  Not enough rust to bother you.   Mac
Reply:I'm betting I could get most of that out with either my 4 1/2" or my 7" grinder once the blade was dropped. Flip the grinder upside down and go at it on an angle to remove a good portion of the weld..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I think grinder too but a real course file would scrape the rust in a pinch.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:Hell, you could even get in there with a sawzall to clean it out.
Reply:so i put a new disc on my 4.5" (found one!) grinder and was able to get it in there to grind out the old weld.  95% of it anyway.  i couldnt get it in to the very far left side (inboard side) of the weld, but i was able to shine it up and thin it out.so i've got the old weld almost completely out and all the metal shined up.Any reason not to use 7014 instead of the 6011?  I'm way more confident with the 7014.  My welds with 6011 always look like poop.  I've never found a "bad" one when i've ground them down postmortem, but my skill level and confidence is lacking with the 6011.If 6011 is the way to go, that's fine, i'll just have to practice before i spark up on the plow.  I think it is 3/8" angles, and i have some 3/8" strap i can fab up some lap joints on which to practice. ... come to think of it, i'll probably do that anyway, just for good measure.I'm out of 7014 so i'd have to get some anyway, but i could get some 7018AC if i need to.  I'd rather not because i don't have a proper way to store it and i'll never use it up before it goes bad.all opinions are welcome!I've heard i should unhook both battery terminals before welding on a vehicle ... true?  anything else i need to know?thanks in advance!mike
Reply:If you got it clean I would use 7018, but use what you want and what you are comfortable with. Even if you don't have a way to store 7018 it will still make very strong welds. Don't know about the battery, alot of people disconect them and alot don't.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:I've got a big handful of 7018 H4R thats been sitting in the front seat of my work beater for about a year or so.  I guess i just wrote it off because it's old and it is not an "AC"maybe i could just use that?if nothing else i could use it for practice ....thoughts anyone?oh yeah .... Merry Christmas!
Reply:If its not 7018ac it may not weld well, I have not done that so I'm not sure. I think Lowes and Home Depot sell 7018ac, you might try that. Run a few beads with it on scrap to see how it does on your ac welder.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:As much as I hate Walmart, they have small pkgs of 7018 AC. I weld on a lot of computer controlled vehicles and I disconnect the negative battery cable and grind a nice shiny spot for the ground on the piece that I'm welding and I've never had a problem.Last edited by RaptorDuner; 12-25-2012 at 10:55 PM.Millermatic 200Hobart Handler 120Victor O/A & Ramco BandsawLincoln 225 ACSnapOn AD HoodMiller XMT304/22AHypertherm Powermax 1650 G3Lincoln Idealarc DC600 w/Extreme 12 VSMiller Digital Elite "Joker"
Reply:Thanks for all the advice. Forecast for tomorrow is calling for a 100% chance of snow .... so i think it might snow  LOLHopefully i can get into town today and find some welding rod. But if not i'll have to get it put back together tonight with what i have on hand.My only concern now is the cold.  It's 2*F right now, and i'd expect the temp to be about the same here tonight when i get time to work on it.  I'd like to preheat, but all i have is a little propane torch.any real problems with welding in very cold temps?
Reply:Couldn't make it to TSC to get some 7018AC, so i had to stop by the farm store and get some more 7014.I did attempt to "pre-heat" ...  i also  ground of a spot for the weld as close to the weld as possible and disconnected the battery.I don't think it did any good though, because when i got to the end of the first weld it started popping and spattering everywhere, so i think there was some moisture or other crap in there.  It did get better when i restarted though, so i don't know what was up with that.In the mean time i tacked up a lap weld and ran a practice bead:135ish amps with 7014.  felt good and i thought it looked good so i went to work on the truck.It was a little hard to get at it, and i wasnt happy with the way the weld started or ended, mostly operator error.  So i did a 3-pass type fillet weld..... or at least my best attempt, anyway.here's where i quit:I always have a tough time with ending the weld all the way out at the end.  and i got too carried away with the pecking hammer ... so that sucks ...but other than that ..... i think it is at least better than where i started, not a "pro" fix for sure, but at least passable, i thinkopen to constructive criticism ... go ahead and be brutal, if you need...  i can take it
Reply:7A749,Good advice, i'll try to get that done after i get done using it here this week.  Snowing now and expecting 5" or better over the next 24 hrs.  Nice to have someone with more knowledge and skill than myself give it a visual, so thanks for that!Since you've been so gracious, if i may:when i grind out the right side, should i do a root pass with 6011, since i already had problems in that area?  What's funny is the right side is where i was able to grind the best and get all the old weld out.  I'm thinking there was just a bunch of crap down between the two angle's that had been building up for a very long time.  I think the original weld was never any good, so there was a bunch of contamination in that spot.I tried some practice beads with 1/8" 6011 @ 120amps and i just felt like it was not controlable, maybe try something closer to 100-110 and try it again?  Perhaps use some 3/32" 6011?Looking at it in the pic i can see that there are some problems for sure.  It looked much better in the cold, laying on my back in the snow   LOL.any advice is welcome.thanks in advance!  Mike