Say what you want about my little 100 amp, 120v welder I do all my welding with a Lincoln SP100 Mig. It's a mere 100 amp welder that operates on 120 volts. I use it in MIG mode with 75% Argon / 25% Carbon Dioxide shielding gas and solid .030" wire. I don't know how many times it's been criticized and I was told it wasn't the right tool for the job and it wouldn't hold up. I welded a Titan 36" weld on thumb on the crowd arm of my New Holland 575E eight years ago . It has 10,150 LBS of bucket digging force. When I welded it on I made 3 passes at each weld point to fill in the curved weld area of the thumb. I have picked up hundreds of stumps and logs with it and dig with it deployed in the 90 degree position. I noticed the thumb wasn't on center last time I parked the crowd arm and just got around to looking at it today. The metal in the crowd arm finally fatigued and broke open. The welds are still intact and holding. I may have to cut the whole thing off to repair the arm but that is a project for the future before I can use the hoe again. Not sure If I will just pound it back together and weld it or cut it off and weld a plate on before I reinstall the thumb. Probably the latter. Just Saying!
Just saying... The welds very likely could have contributed to the failure because the failure occurred in the heat affected zone. Quite possibly from not enough heat input and the steel on the stick became brittle. I think you need to remove the thumb and repair the stick and then add a reinforcing plate over top. Would have to see what it looks like with the thumb removed. Maybe could be straightened. If not may need to cut out a section of the stick and weld a complete new plate in. However it's repaired you need to bevel both sides to ensure you get 100% penetration.
I have a 120v Miller wire feed I use with the gas. It welds very good for a little welder. BUT, when I turn it wide open to get good penetration, it trips the 20 amp breaker. So I run a regular receptacle just for the welder with a 30 amp circuit breaker. Not up to code, but it welds great like that. On something like you are welding, I have a stick welder I use. A used A/C buzz box would be cheap enough, I have a Montgomery Wards buzz box. I just recently put a bridge rectifier on it, got that idea from You tube. Now I can use 7018 rods, and it really makes a nice weld. Get on Marketplace and see if you can find yourself a old stick welder cheap.
I put in a dedicated 25 amp circuit for mine. Regular house recepticles are only 15 amps here.
Did you preheat the boom ?
I don't think so. I'm not saying my methods are correct or professional. My point is the welds didn't break and it lasted 8 years. The WELDS obviously had adequate penetration and strength. I imagine 8 years of stress with a 10,000 lb force being applied to an area that wasn't designed to take it directly did the metal in. I haven't measured yet but this arm material is 3/16" thick at best. When I repair it I will cut the old off and heat and bend it back in shape. After I weld up all the cracked areas I will add some angle or plate to spread the forces out better before putting the thumb back on.
It broke next to the welds, in the heat affected zone. Not 3" away.
Generally you would stitch weld something like that so the boom doesn’t get stressed and possibly break but when you’re welding something that thin you probably should have welded a base plate to the boom first and completely welded than lightweight thumb. Yes the welds held up but you more than likely overheated the base metal on the thumb backing plate. Yes there is a lot of stress there. My Case 580 SE has a factory thumb and the welds on the boom and bracket for the thumb are about as bad as it gets. I assume it’s factory because any photos I can find for an E that has a thumb, all the welds are pretty much the worst, I have ever seen. I realize mig has its uses but if that was a real thumb, it would have been stick welded on, LOL.
Highly doubt the backing plate on the thumb was over heated with a 120 volt Mig welder. There's just not enough heat input with a welder that's marginally rated for 3/16" steel. It's also possible the thicker plate on the thumb sucked the heat away from the boom which further contributed to a quenching effect in the heat affected zone on the boom. The stitch welds probably didn't help either. Yes to putting an additional reinforcing plate on the boom before welding the thumb mount back on. I'd strongly suggest stick welding everything with 7018 or at the very least a 220 volt MIG that will burn .035" wire at 150 amps plus. Thumb mounting instructions I've seen don't recommend stitch welding. Here's a very stringent weld procedure that includes welding the top and bottom some in addition to the sides. Perhaps if the thumb mounts had some weld on the top and bottom of the mounting plates it may not have failed so bad?? Bottom line is it wasn't welded properly or mounting/welding instructions weren't followed. I remember when the thumb was welded on and I got shot down for questioning it... https://aimattachments.com/wp-content/uploads/2018/01/AIM-OwnerManual.pdf
Glad I could vindicate your superior knowledge with it's failure.
Not going to lie, those welds from a little 120 volt mig are impressive. I haven't personally come across a 120 volt mig that could do that.
I use an old school Miller bobcat 225 …no expert but 7018 or Arctec 223 structural repairs on rear crossmember (Ford F7000) washplant etc… no failures yet although bad ‘twisting’ roads, any good loads…. Thanks welder Dave…have learned a lot from you…preheat! Etc.
That absolutely did not fail because of heat/lack of preheat. It failed because there was not nearly enough strength in the stick metal, compounded by the fact it was stitch welded. It may still have failed if it was fully welded, and I'm guessing the bottom weld broke first, and then continued because it wasn't addressed.
It's really hard to tell what all contributed to the failure. It's likely a combination of things. Stitch welding with a low heat input Mig for sure has less strength than a full weld that would add considerably more heat input. Even with a 230 volt Mig they are not the recommended procedure. If the mounts could be welded in the flat position in spray transfer Mig would be considerably stronger. Short circuit Mig is notorious for good looking but weak welds. It is the reason Lincoln was very late in the Mig game. Had proper welding procedures been followed it may not have broke. Partial welds across the ends of the plate may have prevented the failure. There were only 2 short stitch welds at the first stress point on the stick. Once they failed the rest wouldn't be far behind. The welds did fail in the heat affected zone but could have failed anyway because they were just too small and with small welds there is less heat input. It would be interesting to get an opinion from someone who studies weld failures. I'm just giving an opinion based on experience I've learned over the years. Edit: I looked at the pics. again and it looks like the bracket where the thumb pivot pin goes isn't welded at the end of the bracket below the pivot point. That could be the crucial factor of why it failed. Right at the pivot pin is the highest stress point. The good thing is it's fixable if done right.
I suspect that your machine is paying you back for the comment about getting rid of her!!
Don't let any of the comments ruffle your feathers. I have a 480c and it has had a lot of use before I got it. It has welds all over it where the original untouched steel from Case had cracked and someone repaired it. I have welded cracks in the boom, and welded areas in the very thick frame way back beside the transaxle on either side. I guess like anything else, the metal can't take it anymore and cracks. What do you do? Weld it up and keep going.
That’s why we own these machines. Beat on them and fix them up, then, REPEAT! LOL.
There's never a shortage of things to fix. Some simple and some a PIA. Hopefully nothing too terrible.
Bit amazed that the manual thumb held up being as thin as the material looks. I remember your original thread on it but don’t remember the manufacturer, was it Titan?
Yes. It's the Titan 36". Very heavy!
Wow. Lots of opinions from "No Expert". I actually am a welding expert, and you're asking, so I thought I'd give you my thoughts. 1. Those are very clean welds. Sadly, I've seen a lot of "professional" welders who can't run a clean bead. Nicely done. 2. It looks to me like you were a little overly concerned about getting good penetration, so you went slow to let it burn in a bit more, but didn't adjust your pattern and wire feed to match your movement speed. This is what caused the undercut (sunken boarders) around the edges of your welds. The weakest point of any weld is where it meets the steel, so that's something to watch out for. I'm guessing if you'd known how thin the stick is at that point you wouldn't have worried about penetration so much, and your welds would still be holding. Live and learn. 3. I think stitch welding it was a good idea (the main reason for using that method is to avoid over-heating a large area of steel all at once...if you need the extra strength you can fill in between your stitches after it has cooled down). 4. Finally to the main concern: Where to go from here. If that was brought to my shop for repairs I'd cut the thumb brackets off for starters. Then I'd heat and hammer down anywhere the steel is bent out, and fill-weld the holes to eliminate any potential for cracks to grow. Next, I would weld a plate (anywhere from ⅜"-½" thick should be plenty) that covers the entire side of the stick and runs 2" above and 2" below where the brackets are currently mounted, and mate that up with an additional plate on each side (essentially creating a very heavy-duty C-channel wrapped around the stick). Finally, I'd weld the thumb brackets back on. If you do all of the welds as clean as your original welds (watching out for that under-cut this time), it'll still be solid when your grandkids are old. Good luck!
Ravenbane, your theory is very flawed for a so called welding expert. I don't see any undercut but the steel failed in the heat affected zone (HAZ). Have never heard the term "sunken boarders" used by any welder or weld inspector in 44 years in welding. Would it have failed regardless is an unknown. The stick is likely not a high alloyed steel so would be similar to mild steel. Not enough heat input is a much bigger issue than too much on mild and low alloy steel. A 120 volt Mig won't put much heat in on thicker plates like that especially when it's stitch welded with short welds. It would have a quench effect and the same reason preheat is required on thick steel. Peening and post heat (stress relieving) are sometimes required as well. Some large excavators have stress relieved booms. If you're talking about certain alloy steels or stainless steel then you have watch you don't get things too hot. Mild steel, put the heat to it and don't let it cool too fast.
I am curious. I was told when welding a patch plate, to never weld it all the way around. Only weld it on two sides and these two sides should be the short dimension. In other words, the patch plate should be welded down each side of the boom, but not across the boom. If it is welded all the way around, this causes stress and will eventually crack the patch weld somewhere. What do the experts think? It was explained to me that each time you weld, you are heating the metal and it expands. When it cools of course it contracts. When welding the patch above, the boom can easily swell and then contract when welding near the long two edges. But if you weld in the ends, the boom will resist expanding since it is very strong and has already been welded on the sides. So the welded area on the ends will "roll over" on itself. Then when it cools it will be under very high stress from contraction of the cooled metal. I didn't use very technical terms above, but tried to get across what was told to me.
Wow, guess us welders that have been welding and went to school for it and maybe at one time, x-ray certified, don’t know crap. Awesome While I’m impressed at the ability of a manual thumb with what looks like a 1/4” backing plate, it’s definitely lacking. Of course the professional welder can drop 1k in steel and labor, the OP did great with what he had. Yes, it should have a base plate and yes it should be at least 3/8” thick and yes it should be 2” above and below the thumb backing plate, it’s unrealistic to do this to something made out of 1/4” steel. What nice is it will be easy to cut the welds off and grind smooth, hammer it back into place and hopefully build up backing plate and weld back on.
You don't want to weld straight across the stick. You can have curved or a V shape at the ends and partly weld across stick. Sometimes a curved end might be fully welded though. Extending the weld past the end of plate is also used. The weld procedure I linked earlier shows probably the most elaborate way to weld a thumb on.
Another thing Ravenbane got wrong is regarding stitch welds. They aren't done to limit heat input. They're done to save on labour and filler metal costs where full length welds aren't required and wouldn't add any more strength. They can be used to limit distortion as well. Back stepping doing stitch welds is very common to reduce distortion. This is where you want to limit heat input. Not because too much heat is bad but because it causes distortion.You space the welds out to limit heat input and go back and weld in between after the previous welds have cooled off. You weld back towards the existing weld instead of continuing the existing weld thus back stepping.
So I'm reading all the advice being given but I don't know that it will save me from myself. I already had a plan in place and bought some material. I contacted a professional welder friend but he got out of the business and sold his truck with all the welding equipment a while back. If a fella was to buy a used stick welder what would he shy away from? I don't need AC/DC do I? Would 180 to 200 amps AC do it okay? My pre plan and material was to repair all the torn metal on the arm then weld on some angle that will span around the sides to the bottom where the thumb base would weld back on. I bought some 4x4x1/4 angle and was going to trim one leg down for the sides some then trim the bottom legs as needed so it spans up the middle. I have a plasma cutter to trim the metal with. The crowd arm was constructed of two halves and has welded seams top and bottom. I figured I would stitch weld alternating areas to keep from overheating any one area but eventually weld the entire parameter of both the angle and thumb base this time. The bottom center where the two pieces of angle will meet would be welding onto the welded seam of the two halves of the original arm. In addition to not overheating any parts of the arm I have to consider the duty cycle on my welder if I use my little mig. It only has a 30% duty cycle at full power output. It will take forever to try and do this project all the way with the mig factoring in cool down time.
You don't need to worry about overheating the steel at all!!! Not enough heat is much more of an issue. It likely contributed to the failure. Ravenbane doesn't know what he's talking about. Your 120 volt Mig welder is just not up to the task. As far as a stick welder, get one with DC current. AC will just be frustrating and make the learning curve much more difficult. There's a reason you see so many buzz boxes for sale and not many AC/DC machines. 160 amps will generally burn 5/32" 7018 but more amps is better than not enough. A Lincoln Idealarc 250 AC/DC or Miller Dialarc 250 AC/DC are great old school welders that will last a lifetime and burn any rod you can throw at it. There are some decent inverter welders that aren't too expensive. They are smaller and use less power but expensive to fix if something goes wrong. They have a lot of electronics. Some will burn 6010 and some won't. 6010 is a great rod for dirty or rusty steel and has the most penetration. It is often used as the 1st pass or root pass and then welded over with 7018. 6010 and 7018 are probably the only rods you'd ever need. 6013 are garbage rods only good for sheet metal. 7014 is a better choice for things that don't need max. strength. For the repair, it would be better if you had a 3/8" backing plate on the stick. You could vee the ends and partially weld them leaving the center 2 1/2" of the vee's unwelded. Refer to the link I provided on mounting a thumb in post #9. The backing plate should extend past the thumb mount 1 1/2 to 2" on each end. On the actual thumb U shape the sides should be fully welded as should the backing plate. On the ends you could go around the corners about 3/4" or cut a small vee in each end. Cut the backing plate slightly narrower than the width of the stick so it's easy to weld. If it's wider there will be a gap where the backing plate goes over the rounded corners of the stick that will make it difficult to fill with weld. It's the one place you have to watch you don't get it too hot. Not because too much heat will weaken the weld but because the large weld puddle to fill the groove could burn through. That's the last thing you want! With the backing plate having the vee's on each end and properly welded you shouldn't have to worry about it pulling off the stick and the thumb mount will be securely welded to it. Oh, don't weld downhill with 7018. There is very little penetration and you get a concave bead. 6010 uses a back and forth whipping motion and can be used downhill a lot of the time. 6011 is similar to 6010 but not as quite as much penetration. It is a little easier to use though.
Ran out of time to edit above post. Just wanted to add that you should weld about 6" at a time alternating between each side to keep everything straight and reduce weld stress on the backing plate and thumb.
Why do all this ? You showed us how you did it the first time, and said the 8 years of usage was good enough. Weld it up again the same way, and re-start the clock.
Because I would rather it not break at all. I am near done with this machine so it may go down the road when I am. Now that I know it failed at 8 years I can't bring myself to do the exact same thing again. I will have to try and improve on it.
Thanks for taking the time to explain all of this. I will see if anything comes available used on the welder front. I'm not going to buy a new one at my age and have it sit in the barn but if I find something for a couple hundred bucks I will add it to the pile of stuff my daughter and SIL will inherit.
You might be able to rent a stick welder. I'm sure you could rent a small gas drive for not too much. You'd want to do some practice or try to get an experienced welder like your friend to do the welding. It's a little different than Mig. You're smart to want to do a permanent repair. If the stick were to fail again, then you'd have to worry about metal fatigue in the stick. I bought a thumb several years ago but haven't got around to installing it. The stick on my Cat hoe isn't flat where the thumb plate gets welded on. It has a long tapered plate on that side over top of the normally flat stick. I need to make a plate(s) to go around the tapered plate so the thumb has a flat surface the full width to weld too. Interestingly the long tapered plate is fully welded all around from the factory. From your experience I know I need to make sure it's as solidly mounted as possible without compromising the stick.
I have used a stick welder a few times in the past. Just enough to know I don't know how. My biggest problem with an arc welder is controlling the changing distance of the hand piece to the work. I have bad nerves from too much Sevin Dust as a kid on the tobacco farm and I need something to rest against to even mig weld. If it turns out I need more heat a larger mig welder may be a better choice for me.
I wish you guys that need/want a stick welder lived closer. I wanted a AC/DC stick so I got the stuff I needed from a 3ph welder and put on my buzz box. Then I was at a auction and bought 2 small AC/DC welders . Then I went to another and bought 2 bigger better AC/DC stick welders and sold the 2 small ones real cheap. I now have one of the others I will try to sell or scrap. I have less than scrap value in it and I would sell it for that.
I am not a welder. But I have done my share of welding in my career in maintaining and repairing machinery. I love a 6011 rod. It holds like crazy. It burns through paint, rust dirt, etc. It starts very easy and it's easy to stop and start when you are filling holes and welding something thin. The only thing not so great about it, the finished weld doesn't look that great. If you use A/C, there will be a lot of splatter and the weld will look rough. But it will hold like the dickens if you get good penetration. DC with the 6011 seems to lessen the splatter and makes the weld look a little better. But doesn't seem to help the weld hold any better. Since I put the bridge rectifier on my A/C buzz box to turn it into a DC machine, I can now use 7018 rods. I used to use them at work on a regular basis. They can be a little hard to get started. But once you get it going, it makes a very nice weld that holds really well also. The weld looks so good and is so easy to lay down with this rod, someone may make the mistake and think I know what I am doing. P.S. About keeping the proper distance for the stick when welding; With the 7018 you have to be a little more careful, but with the 6011 once you get a puddle going, you can just lightly put it in the puddle, you can actually feel the stick melting away on the end. Like was said, practice a little bit first. Also the 7018 can be a little more touchy as far as humidity and moisture getting into the rod. 6011 doesn't really care too much about this.
I have a new plan. It dawned on me that since I added the thumb I also acquired a larger John Deere tractor that I added a grapple on so I have less need for the thumb. Also I am no longer digging stumps to pull out and just have a few trees I am taking down with the stumps attached. All I need to do from here is cut stuff small enough the grapple will handle it which I am already doing. The new plan is to cut the thumb off, repair the stick, and leave the thumb off for now. My little mig is plenty capable of welding the metal the stick is made out of. I will reshape and weld it all up then anneal it with a rosebud to relieve any stress created. Without the thumb it will no longer be stressing the damaged area. I will miss being able to pick up whole trees to position them but I can work around that.
You don't need to heat it with the rosebud after it's welded. Preheat it to a about 300 deg's. before welding and bevel both sides leaving a little gap in middle. Your Mig will easily bridge the gap. Keep your arc right on the bottom edge. You want some weld build up on the inside. You can't see it but it should look like it was welded from the inside.
Had to get it dull red to bend it back in place. Nothing I can do about the top where it bent inwards a little but it's not bad. At the bucket end it ripped a couple of pieces out about 1/2"x3". I had to cut some filler pieces out of 1/4" scrap to fill those. Got about 2/3rds of it done today. The thumb has doubled in price so I should be able to get my money back out of it.
I do love my propane weed burner for a preheat torch and dozens of other uses, clamp it to a sawhorse or anything to hold it fast and let it warm up a big area. Also have a trash can sized propane space heater, drop a 3/8 plate on the top and leave it on medium. When winter comes put all your wrenches on the plate and they stay toasty warm to keep the chill out of your fingers. Less of a concern in Fla!
so sometimes to bend stuff in or out, I'd take a 2' piece of flatbar, stand it up on end so it bridges the crack, tack weld onto the part to be lifted with the other end on the base metal, heat it up and lever the flat bar to pull the recessed piece up and then add some tack welds on the crack.
Someone liked one of the posts in this thread and brought it back to my attention so I decided to follow up. Like I said at one point my need for the thumb has lessened so I probably won't put it back on. I do appreciate everyone's input and helpful suggestions. This is what the arm looked like after cutting the thumb off. This is what it looks like after welding and filling the holes and priming it. I used a flap wheel to smooth it out some. It ain't pretty but I don't expect any problems out of it. The middle seam on this arm goes all the way through. The factory design is actually two formed tubes welded together. I haven't been able to match the faded paint so it will probably just stay in primer. Also an update on my welder. I came across the PrimeWeld 180 multi-format welder and was impressed with it. The price was too good to pass up at $549 before tax with free shipping. It can mig, stick, and even comes with a spool gun for welding aluminum at that price. So after all my bragging about my SP100 I broke down and bought myself a new welder. It runs on 120V or 240V but I went ahead and put in a 240V, 50 amp circuit next to my 120V, 30 amp circuit. After selling my Lincoln for $175 I was into the welder for $415.18 not counting the electrical upgrade.
I think you will be much happier with the 230v.
I'd see if New Holland had a close paint or go to a body shop supply and match it. It might be the pic. but the primer makes the stick look like a beat up mess. Not the best if you're planning to sell it.
It is a beat up mess from the thumb. I agree it detracts from the appearance but I don't think paint will do anything to mask that. Especially off color paint. It doesn't look as bad in person to me but it will stand out and be questioned. If I sell it I will price it taking it's flaws in consideration. New Holland changed the color on the tear after my machine was built so the old color isn't available in the aftermarket. No way to match dull faded with new glossy anyway.
Regarding paint matching, check with your local Sherwin Williams store. Take a paint chip with you, they have a machine that will read the paint chip and probably come very close to what you have.
^^^^^^ for metal outdoor paint? I have used the paint chip things a few times, was never that happy. Best I would do, is buy the correct paint and when dry and degassed, I would run some red or grey scotch brite pads over new paint to dull it, then put a satin clear coat over it. Works pretty good. Honestly, not sure how I would feel looking at that 555, with the primer, especially knowing what you’ve already said you kinda want for it. Now, knowing exactly what work you have put in it, I would have no issues. Unless you can sit some prospective buyer down and have him go threw all the posts, not sure you will get the appreciation due, you and the machine. It would look better patched up a bit, in my opinion.
I have used them a few times and it was not a perfect match but the person operating was very knowledgeable, Some people may not have the knack or experience.
Good autobody shops can match paint. I wouldn't be surprised if there's a paint code for Ford/New Holland. I don't know if Sherwin Williams does machinery paint. I agree with HappyHarley. The 1st thing a prospective buyer will cast their eyes on is the stick. Make it look as good as possible or it could cost you thousands or even a sale. First impression is abuse and what else was abused.
The whole machine is weathered looking so it isn't going to bring restored value. The fenders look worse than the stick. The fact that the hours are unknown is as big of a detractor as anything. ANNND if nobody wants it it has a place to rest in my barn. It fires up, runs quiet, and has good power. AC blows cold and it even has a new radio. Cold AC will make up for a lot down here.
Matching the paint shouldn't be that hard and could help you get more money. The primer is pointing out a potential problem.
You could always bury the ol' girl in her own hole when you are done... No income from that but it seems a fitting end. Except your holes that deep probably fill with gators fast.
I tend to agree with you. Welder dave made some good points also. The op did not have enough strength in the assembly. I would have put in a longer plate that spread the force over more area and combine with length welds. Those thumbs can get an incredible amount of pressure on and constant movement. Once it starts flexing the base metal starts cracking for me at the weld meets plate joint. I look for cracks in dirt and oil to find the weak spots. Proper maintenance and re-welding the cracks before they tear open is key. On grapples it is a yearly or bi-yearly item. To me the welds he did looked great just not enough there for the power of that tractor My go to repair is to plasma out the cracks following it till it disappears. Then filling the crack. Then laying new weld over the fill and getting the new weld to fresh plate. They have been many excavator arms completely twisted and destroyed because of thumbs and large logs. Your damage is not much compared to some I have seen.