How would you repair this? Weld/Fab on excavator bucket

[Greg]

I figure we have enough guys on here that weld, fabricate and even work on heavy equipment for a living... might as well get some opinions.

This bucket is about 3 years old, cost $20k new has been used to ditch and move lots of Granite rock over the last few years. It's wearing on the back side of the bucket to the point that the seam is showing and its probably wearing thin. We could send it out to a welding and machine shop and have it rebuilt, but I don't think it's ready for that yet. And a field repair would be much quicker than sending it into a shop.

I'd like to extend its life, get more use out of it before it needs to get rebuilt.




I'm thinking about buying 1/2" thick AR (abrasion resistant) steel plate, having it cut in 2" wide strips and welding the pieces horizontally around the curve of the bucket, with just enough gap between the plate for a solid weld, capping the welds with hard facing rod.

Tomorrow I'm going to see what the local CAT dealer has for weld-on wear bars, they would be a high carbon steel plate.

Any other ideas?

 

[bryson]

From the pic you posted, it looks more like a gouge/scrape and not necessarily the seam you're looking at... maybe. I'm sure it looks different in person. What about just grinding it out to make it clean and then just weld it up and hard-face it?

 

[Greg]

From the pic you posted, it looks more like a gouge/scrape and not necessarily the seam you're looking at... maybe. I'm sure it looks different in person. What about just grinding it out to make it clean and then just weld it up and hard-face it?

Yeah, it looks like it... but that's 100% the joint where the floor of the bucket is welded and connected to the side. It's the same on the other side. The pics don't really show it well enough.

I plan to weld up the crack, build up the edge again with hard facing and then add wear plates to add even more life.

 

[Greg]

Found this online...

"If you run the wear bars from tooth to heel you still get wear on the floor where it is exposed. The dirt & small rocks are still scraping/grinding on the floor bottom. This in turn weakens the floor after a while. If you run them from side to side the spaces in between the wear bars fill in with dirt effectivly creating a "shield" for the floor in the exposed areas. Even if the dirt falls out it keeps getting replaced & also you wont get as much abrasion there as the dirt protects it. If you are in rock, the rock mainly passes over these areas also."

So a wider gap between wear bars would be OK. I think 2" strips with a 1" gap would be sufficient.

 

[1969honda]

From what I've seen in the past I think you are on the right track. AR plate in 2" to 3" wide strips from side to side, say 1/2" thick and 1"-1.5" gap to allow good welds and spacing.

Inner shield wire welding or stick was what Wheeler CAT was using for dozer blade plating. That was almost 20 yrs ago when I did a short stint with them between semesters in Logan.

 

[Greg]

From what I've seen in the past I think you are on the right track. AR plate in 2" to 3" wide strips from side to side, say 1/2" thick and 1"-1.5" gap to allow good welds and spacing.

Inner shield wire welding or stick was what Wheeler CAT was using for dozer blade plating. That was almost 20 yrs ago when I did a short stint with them between semesters in Logan.

Good to hear, sounds like that's how the pros do it! It'll be interesting to see what the CAT dealer says.

 

[Greg]

Some good tech about welding AR to mild steel, sounds like preheating is needed to prevent cracking.

Three Common Challenges of Welding Abrasion-Resistant Plate, and Their Solutions - Hobart Brothers

Welding abrasion-resistant steel plates, commonly called AR plates, presents several unique challenges that welding operators should know how to address in order to maximize their effectiveness and efficiency.

www.hobartbrothers.com

I was planning to stick weld this in the field, but I have access to a massive dual shield Miller XMT 350 Mig in my shop. It burns HOT and heavy welds and I feel much more comfortable with Mig. I'd have to remove the bucket and haul it 90 min away. It would be a ton of welding, probably take a full day or two to get it done.

 

[1969honda]

I tend I treat my civilian job repairs like my military repairs. Anything indepth done in the field, is triage, until I can actually get it to the shop. Conditions are more manageable and work area is better suited to quality. Not that quality can't be done in the field; but wind, dirt, light, etc are never ideal.

I would think UP would be much happier with spending the funds to have you remove/reinstall the bucket and drive it to the shop for a long term repair vs a temp on $20k bucket, even if the temp last 5 years vs 8.

 

[Greg]

I tend I treat my civilian job repairs like my military repairs. Anything indepth done in the field, is triage, until I can actually get it to the shop. Conditions are more manageable and work area is better suited to quality. Not that quality can't be done in the field; but wind, dirt, light, etc are never ideal.

I would think UP would be much happier with spending the funds to have you remove/reinstall the bucket and drive it to the shop for a long term repair vs a temp on $20k bucket, even if the temp last 5 years vs 8.

Fully agree, I know I'd do a much better job in the shop with a mig, versus in the field with a stick. The biggest issue is the downtime with the machine being out of service, with the bucket removed. That machine is basically on emergency standby, to move rocks and slides that come down in the canyon... and that's happening frequently right now. Shop repairs will need to wait until after the Spring thaw and rocks getting knocked loose.

 

[STAG]

Found this online...

"If you run the wear bars from tooth to heel you still get wear on the floor where it is exposed. The dirt & small rocks are still scraping/grinding on the floor bottom. This in turn weakens the floor after a while. If you run them from side to side the spaces in between the wear bars fill in with dirt effectivly creating a "shield" for the floor in the exposed areas. Even if the dirt falls out it keeps getting replaced & also you wont get as much abrasion there as the dirt protects it. If you are in rock, the rock mainly passes over these areas also."

So a wider gap between wear bars would be OK. I think 2" strips with a 1" gap would be sufficient.

Current heavy equipment engineers are designing plates in large haul trucks to intentionally trap dirt and rocks in between the plates that doesn’t come out during dumping. The practice behind this is proven to drastically reduce wear on the steel, because when the load gets dumped out, the dumped dirt slides over the dirt trapped in between the wear plates and not sliding on the steel itself.

 

[STAG]

Some good tech about welding AR to mild steel, sounds like preheating is needed to prevent cracking.

Three Common Challenges of Welding Abrasion-Resistant Plate, and Their Solutions - Hobart Brothers

Welding abrasion-resistant steel plates, commonly called AR plates, presents several unique challenges that welding operators should know how to address in order to maximize their effectiveness and efficiency.

www.hobartbrothers.com

I was planning to stick weld this in the field, but I have access to a massive dual shield Miller XMT 350 Mig in my shop. It burns HOT and heavy welds and I feel much more comfortable with Mig. I'd have to remove the bucket and haul it 90 min away. It would be a ton of welding, probably take a full day or two to get it done.

My dump truck bed was built entirely out of AR450 plate for the bed cavity itself and tailgate, and then just mild steel for the fenders, taillight housings etc. it was custom ordered by my brother and I know for a fact that the shop that built it did no special preheating treatments. They also built the bed on my brother’s dump truck the same way.

No more cracking or premature failure than any other regular wear-and-tear that a bed sees, but the AR plate does make it much more resistant to wear, as a large majority of what those trucks haul on the daily is large sandstone boulders (like ones I delivered to @skippy’s house) and gravel.

 

[UNSTUCK]

I've done many, many bucket repairs in the field. Can't say I've ever used AR plate. Do like you said, get the Cat wear strips and weld them horizontal with the spacing the same width of the wear strip. What you posted is right, the dirt fills in and acts as a cover and protector. You'll get good wear. I like dual shield for these jobs, but I've done plenty with 7018 just fine. Open up that crack and fill it in on both sides. Do a cute hard face pattern as well, if you like.

 

[Hickey]

CAT should have corner wear blocks you can buy. It’s basically small squares of hardened material. Space them out as you mentioned above. They should also provide instructions on install, such as preheat or nah. Be careful with preheat on AR, it doesn’t take much heat to remove the hardened treatment.

 

[Hickey]

 

[Greg]

CAT should have corner wear blocks you can buy. It’s basically small squares of hardened material. Space them out as you mentioned above. They should also provide instructions on install, such as preheat or nah. Be careful with preheat on AR, it doesn’t take much heat to remove the hardened treatment.

The Hobart article mentions preheating temps for AR and its only 200* for 1/2" and not to exceed 400* for that exact reason.

 

[Greg]

Found bucket heel shrouds that protect the edges of the bucket from CAT, they're $55/ea. I think 4-5 of these per side, plus the AR plate along the floor should go a long way in making it last.

https://parts.cat.com/en/catcorp/280-4079

I got a quote for 45" x 30" of 1/2" AR plate and it's $500 for just the plate, without the cuts.

 

[Greg]

Spent most of the week getting this done, it was a much bigger PITA than I expected.

I ground the cracks out and filled them back in. The dual shield Miller I have access to was having issues, I ended up using an OLD Miller stick with 7018 for most of the work. I added 4 heel shrouds on each side, with 1/2" thick x 2" wide AR 400 strips. I covered the 7018 with hard facing rod, to keep wear at bay.

Most of the welds didn't end up looking great, far from my best welding work TBH.

The bucket has a couple dents in it, I used a chain and a bottle jack to get the AR strips tight so there wasn't a big gap to fill.

Should last awhile... 🤷‍♂️

 

[UNSTUCK]

These kind of repairs are my favorite. I could do them all day.

 

[Greg]

These kind of repairs are my favorite. I could do them all day.

I'd have felt better about it with a working MIG, I'm not the best with Arc welding... but I did get a lot of practice! It was pretty warm a few days, even though I was in a shop, I was sweating pretty good. I spent 4 full days on it!

 

[UNSTUCK]

I started the welding portion of my career stick welding, out of a service truck. I repaired many buckets that way. It is slow but worked well. I then got in a shop more equipped for these repairs. Air arc and dual shield changed everything. I was amazed at how much faster and easier those made these kinds of repairs.