75/25 or 90/10 for welding loader arm?

[Steve Bowman]

I have been looking for an excuse to try a different shield gas lately.

For all of my general welding, I have been using 75/25 as that is what my supplier normally carries. But have the option of getting some 90/10.

I was planing on using(making due) my normal .035 solid ER70s-6 wire. Welder is Millermatic 210.

Anyway, the boom is 1" plate steel. Will be welding a "crack" in the upper section of the arm , and two new bushings for the bucket. I mase the "crack" in order to straighten a bent portion of the arm.

Does the 90/10 produce less spatter and potential for better finish, while the 75/25 better penetration?

Maybe just use the 90/10 for the cover passes?

The boom is off of the loader. Most welds will be made in flat position.

Thanks

 

[Steve Bowman]

Been thinking about preheat. The prevous, extensive repairs where done cold, so i don't see much sense in it, but it seems to be a common recomendation.

 

[Nige]

Not a welding expert by any means but some preheat (100C or thereabouts) surely can’t hurt.
Do a search on HEF for “runout tabs”. That weld repair would definitely benefit from them.
Also a needle gun to peen and stress-relieve each pass would be another suggestion.

 

[gtermini]

90/10 is for spray or pulse spray. It doesn't short arc as nice as 75/25 in my opinion. I don't believe your 210 has the nutz to get into true spray transfer. I'd just run the 75/25 if that's what you have, as hot as you can get it. Preheat and gouge out anything you don't like the looks of. I'd probably put a fish plate across it too.

I wouldn't be afraid of getting a roll of .035 dual shield and burning that joint uphill to get as much heat out of the little miller as possible.

 

[Junkyard]

Preheat is always a good idea. Gets things dried out and warmer so the welded area doesn’t cool as quick. The mix and wire you have should be fine with proper procedure. I wouldn’t be afraid of a pass or two on one side then grinding or gouging the back side out enough to make sure it’s clean and penetrated well. Then weld it up alternating sides to keep from pulling one way or another. Anything like that we also wrap up when we’re done so it cools slowly.

X2 on a fish plate.

 

[Nige]

Here's the info on runout tabs. I think they would be ideal for that repair in that you would be able to establish the arc and terminate it outside the length of the repair. As a rule of thumb the length of the masurement highlighted in yellow should be about double the thickness of the plate you are welding. The tabs get cut off afterwards with a cutting disc.

 

[Steve Bowman]

Thanks for the info guys. Will do some preheat and lay into it. I undertand that some have spray welded with the 210, but that's it's very upper end.

As I mentioned, there have been 4 or MAJOR repairs done to this boom. The loader lived a very hard foundry life before I got it.

As you can see in the picture, I pulled it in several directions after cutting it. Laying on my bench, it was pretty close just looking at it, but when i ran a long shaft between the eyes, it definitely lacked some. Given the fact that the pin bosses on the loader frame had also been repaired, i thought i might not have much to loose by just using the frame to help align the bores.

Glad i did. With one pin in, and the other only 1/2 in, i could see the rest of the boom was out of level. I pulled down right at my hinge, which leveled out the rest of the boom.

Fortunately, the cut i had made allowed for some adjustment. I ended up with a much bigger gap to weld, but both upper pins sliped right in/out.



Not so sure how well a fish plate will fit over that. Kind of nasty, but the twist i was compensating for was spread over a couple of feet.

 

[Nige]

That needs lining up and welding, then line boring IMHO. I don’t care how well the welding is done, the structure will always pull to a certain extent no matter how well it’s stress-relieved, and the pins won’t fit any more.

 

[Steve Bowman]

You're probably right, but these are factors that effected my compromise...

1. the bores are still good
2.the arm is twisted, and forces needed to twist it back are beyond my resources.
3. I am not setup to linebore, though i did consider modifying some old lineboring equipment i have acces to.
4. Intended use is "just" on my farm.
5.low budget.
6.on site cutting and welding capabilities.

Here is what i was dealing with...
Nearly 5/8 twist in the arm I cut. The other side was less than 1/16 out.

 

[Welder Dave]

It's going to be a bit tricky but can be done. Gtermini was bang on regarding the shielding gas and welding. I just don't know if an MM210 is enough machine for the repair. Preheat to at least 200F deg's. Mounting on the machine is good for one end but I'd get a bar or heavy wall pipe that is a fairly tight fit (machined if required) to fit across the bucket mounts and the holes for the linkage further up the loader arms. I would also weld braces between the loader arms close to where the pins go to keep them at the correct spacing. It moves 1/16" and you'll fight to get the pins in. The nice thing is the break has enough room to move during the welding and cooling process and won't make a lot of difference if it isn't completely flat with a straight edge as long as all the pins fit. This is a perfect example of where to use run off tabs as Nige has mentioned. The gap to fill adds to the excitement. I think the easiest way to fill the gap once everything is clamped straight is to put a piece or round bar or flat bar in the middle and once you get enough weld on one side, grind/gouge the round bar out from the other side so you have 100% penetration. Wrapping the weld in a fire blanket or some insulation when completed to let it slow cool is a good idea in addition to peening between passes. More passes ran as hot as you can make a sound weld are better than 2 or 3 heavy passes. Reinforcing plates should be oval or diamond shaped and you can cut some holes in the them for plug welds. I agree on .035" Dual Shield as well. Something like the Lincoln 71M below.

https://www.lincolnelectric.com/ass...Shielded-Outershield-Outershield71M/c3101.pdf

 

[StanRUS]

Steve, if you want bit more penetration use CO2 shielding gas with Outershield 71M or similar wires from Hobart (Elite-Arc) or ESAB (DualShield); they're designed for both types of gases and all position welding.

CO2 is a reactive shielding gas; you'll have a bit more smoke and sparks, but reduced gas cost.

I would be using 'cold water spray > water fire extinguisher' to move the plate around and straighten during the welding process. Then fish-plate with the plates tapered @ ends to 30 degrees for reinforcements. Probably cut off both pin-bore bushings and align with a precision bar and re-weld after the arms are repaired. Home DIY project? Paying customers, cheaper to make new bushing and align bore.

Good luck

 

[Nige]

Steve, understanding the circumstances and constraints regarding line boring would convince me more than ever to use a needle peening gun to stress-relieve every weld pass after it was laid. At least it might give you half a chance of getting away with keeping things in line and not having to re-bore.

 

[Steve Bowman]

Yea, home DIY. Will definitively take the advice and get some 71M, preheat and needle scale. I have some good material to insulate and let cool down slow.

I definitively know that welding up and lineboring is the correct way to go for a paying job. But as rough as the boom is, i have little to loose other than my time.

 

[Welder Dave]

Was the original crack completely through? It would have been better to leave the bucket on and get everything lined up and braced before working on the repair. I think the only way to possibly avoid line boring is to have tight fit shafts going through all mounting holes on the loader boom and have some heavy bracing welded on the rest of the loader boom. Even still you may need to do some heating to get things straight and lined up when completed. During the welding process I don't think I'd want to be using water to control distortion. You want to get the repair hot and keep it fairly hot till the repair is done. Peening will help to keep from getting it too hot as will welding from each side. After the crack is repaired then you could use some heat shrinking techniques if required. This is a pretty major repair and the twist may be in or near where the cross member for the bucket cylinder attaches. I'd do a lot of checking and measuring to try and determine where the twisting originates. It may be beneficial to heat or cut the welds on the cross member to get the 2 sides parallel and level. What make and model is the loader? If it's common you may find a decent loader boom on a scrapped machine. It would save you a ton of frustration.

 

[StanRUS]

Was the original crack completely through? It would have been better to leave the bucket on and get everything lined up and braced before working on the repair

I just downloaded #1 photo / post 7. Dave is correct, 'would have been better.....

I would reinstall the loader arms and pin up to the loader frame and lift cylinders / 4ea pins. Measure the lift cylinder stroke to be equal and level (machine) and across the arms @ the loader frame and straighten, shrink working forward.
Peening after each weld pass. Not required because the weld joints are not highly restrained; just the opposite, those arms will walk around like wet noddles. The only areas that are restrained are @ the large crossmember.

Material? Grade50 A572 maybe... Outershield 71M 0.035" is tiny wire, turn up the amps (wire speed / voltage)

 

[Steve Bowman]

I may need some more education on the flux core wire.

I dug out a partial roll that I have. It's a E71T-11

From what I gather(and how i used it in the past) it is a gassless flux core, which may be different than something like an E71T-9 or GS that mentions the addition of the gas?

Correct?

 

[StanRUS]

E71T-11 is a Innershield wire. The internal flux creates the shielding envelope @ the weld puddle.

E71T-11 is a general purpose, all position wire used for general fabrication, repairs and also multi-pass welding.

Lincoln example NR-211, limited metal thickness 1/2" for wire diameters 0.068" / 3/32" Also not impact rated, per Charpy-V notch test.
https://www.lincolnelectric.com/en-...rshield-innershieldnr-211-mp(lincolnelectric)

Very popular wire, but you'll have chip flux and lightly grind after each pass when doing multi pass welds. STRAIGHT POLARITY and low deposition rates compared to external gas shielded wires.

Small diameter NR-211 like 0.030-0.035-0.045" I consider as sheet metal wires. I carry a 25lb roll of 0.045" to use for filling open weld fillet gaps caused by guide rollers' edges rubbing. External gas shielding doesn't work will in that application because of breeze/wind disrupting the shielding gas flow.

Impact rated self shielding Innershield wires like Lincoln's NR-232/233 SEMA approved cost over twice as much versus Lincoln's Outshield wires...$4.50-ish versus $2.00 per lb @ jobber wholesale cost.

NR-232/233 welding procedure is critical; demo video

 

[Steve Bowman]

Cool, thanks. Will chew on that a bit.
But, it IS different than an outershield flux core with gas?

I figured i would be dealing with slag either way with any of the flux core wires.

 

[Welder Dave]

NR211 would be like welding the repair with 6013. About the worst choice possible and the other Innershield wires are like StanRUS says are quite a bit more expensive and ten times more smoke. A Lincoln rep told me years ago that the white stuff floating in the air after using NR211 is like milk and won't harm you. Yes a Lincoln rep. said that. I remember looking at the test procedures for NR211 and it took 20 some passes on 3/4" plate to meet specs. The gas shielded Flux-Core(Dual-Shield) is the best wire for this repair. When the weld is done properly slag is easy to remove from flux-core but I'd use a wire brush in a grinder and have a grinding wheel ready if any flaws or inconsistences show up in the weld. If you wanted to peen it some a needle scaler would remove the slag. My personal choice would be to stick weld it but maybe I'm a little old school. I might use solid wire Mig for the initial passes to fill the gap being that it would be ground or gouged out from the other side. That said you really need to figure out why the gap got so big. Measure the distance from loader pivot pin on the machine to the pivot pin for the bucket on the good arm and compare it to the cut apart arm. You also need the width of the arms at the bucket the proper spacing. Get those measurements accurate and then measure diagonally from the same pivot pin locations, ie/ top left on loader to lower right on bucket. It needs to be the same on both sides or darn close. It needs to be corner squared the same way a steel skid would be. Then you want to be able to slide line up bars in the bucket, lift cylinder and linkage holes. If everything is straight they should slide in but putting the line up bars in first could help keep things from moving too much when trying to get everything straight. I'd guess you're going to need a big rosebud or 2 get things lined up but get it as close as possible at the start of the repair.

 

[Steve Bowman]

Thanks, but i have a disconnect between the NR211 and the E71T-9 wire. We are talking about different wires, no? I tend to agree the e71t-11 i have is not correct for this repair.

The gap got so big because of some(many) repairs. While the repairs are sound, it seems that the upper pin bushings/bores on the loader frame where replaced. It seems that they may not have been not lined up correctly.

At some point, it appears likely that one of the pins fell out or broke with a loaded bucket. The subsequent severe missalignment twisted the upper section of the loader arm thst remained attached. Including the mounting point for the lift cylinder.

Had the major twist in one arm have not been present, i would have chose a different repair method. I used the spacing between the arms at the center lever weldment as my reference. Even that area had been broken in half an repaired in the past, but, that area damn sure was the most solid part of the boom.


I am not worried about the bucket mounting points. Those will be new. Including fabricating a quick tach for skid steer buckets/attachments. And, they are no longer available to measure from.