reskinning a bucket

[MTNGUN]

Neighbor's other backhoe bucket. The bottom was worn thin, then punctured while pounding fenceposts. It has other things wrong with it, too (note the missing teeth), but I only signed on to reskin the bottom.
http://i487.photobucket.com/albums/rr235/mountainmolds/old_bucket.jpg

The old skin was cut out with an oxy torch and a 4 1/2" grinder was used to clean up the edges. An air-arc would have been faster, but Santa hasn't brought one yet.
http://i487.photobucket.com/albums/rr235/mountainmolds/oxy_bucket.jpg

Rebar was tacked inside the bucket to guide the new skin as it gets bent around the curve of the bucket.
http://i487.photobucket.com/albums/rr235/mountainmolds/rebar_bucket.jpg

I cut the replacement skin out of 1/4" mild steel plate -- the same plate that I used to make my truck bumper (which is why I made the bumper out of plate). I had no way to brake the plate to the contour of the bucket, so it will have to be bent and tacked a little at a time.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack1.jpg

[MTNGUN]

I've never reskinned a bucket before, so I wasn't sure how to bend the 1/4" plate. I thought about making a brake attachment for my 20 ton press, but I don't think the 20 ton press is sturdy enough to bend 1/4" x 24" plate. So I improvised.

I started out using a come-along to bend the plate.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack2.jpg

The come-along quickly ran out of room to manuever
http://i487.photobucket.com/albums/rr235/mountainmolds/tack3.jpg

I added some levers and switched to a farm jack. The farm jack had plenty of power for the job, but it wasn't a real stable situation, and I don't recommend doing it this way, even though I made it work.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack4.jpg

This was as far as I could get with the jack.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack5.jpg

[MTNGUN]

This is as far as I got today.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack6.jpg

Tomorrow I will finish tacking the plate.

In hindsight, it would have been easier -- and safer -- to use the loader bucket to bend the plate. But, that's hindsight, and the backhoe is 7 miles away, with a flat tire. I made do with what I had available.

I curious to hear Torker explain how pros do this job ?

[boslab]

Good job, i did one on the machine [i have another to do weather permitting so i'll take some snaps] i used the machine to bend the sheet round after it was welded at the top by the hitch and piled the weld in from inside the bucket, rooted with stick capped with MIG [it was windy so working inside the shell stopped the shrouding blowing off] but as you did not have that luxury i think that would be the way i'd have at it.
Good job well done
regards
the other
Mark

[torker]

MNTGUN...I do it the same way but I use those little chain comalongs...they are shorter.
Where you are now...I would use draw down wedges on both sides if I had to....
BUT...I wouldn't....I'd weld two lugs on the sides...then loop a chain thru that and up over the top of the plate.
Put a hydraulic jack on the plate (with a U shaped adapter for the chain to run thru)...run the chain over the jack....pump up the jack till it bends the plate down and you got it!
You'll need wedges for the last bit no doubt. Just cut 1" or so holes on 1/4" plate ...tack it to the sides...run the wedges in from inside to out....and you'll suck the plate down very tight!
Russ

[MTNGUN]

Torker, I like your suggestions on the wedges and chained jack. I hadn't thought of either of those tricks.

However, the new skin has started to run crooked, with 1/4" gap on one side while rubbing on the other side. I was thinking to torch off the remaining plate so I could reposition it in the center of the bucket. The remaining section has very little curve so little or no bending would be required if I cut the plate.

Thanks for the feedback, Torker. One of these years you'll have to show us one of your bucket repairs.

Looking forward to seeing your pics, boslab.

[Errol]

I would be tempted to use some heat. But remember to keep your torch moving. I've done quite a few curves by tacking and torching including a bucket bottom that I built quite a few years ago. Careful or you will get "lumpies"

[AussieChris]

That's what one of my hoe buckets looks like. Thanks for posting this thread and giving me some ideas how to repair it.

Chris
Brisbane Australia.

[MTNGUN]

AussieChris, glad this thread is helping you. But, I am just an amateur welder. Torker is the master bucket builder.

Anyway, taking up where I left off...... since the new plate was running a little crooked, I cut it off so that it could be reoriented.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack7.jpg

Refitted.
http://i487.photobucket.com/albums/rr235/mountainmolds/tack8.jpg

The curved part of the bottom did have a slight convex bow, so I employed Torker's excellent suggestion to use a bottle jack and a chain. The bottle jack easily straightened out the bow. Thanks, Torker.
http://i487.photobucket.com/albums/rr235/mountainmolds/bottle_jack.jpg

I'd been tacking with KT 3/32" 7018, but finally used it all up, so I opened a new 50# can of Lincoln 3/32" 7018AC. I bought the 7018AC because it seemed like the logical choice for my buzzbox, even though I normally run DC. However, I have since heard that 7018AC does not run as well as normal 7018. That proved to be the case.

My first serious effort with the 7018AC rod, dragging at 85 amps DC. Not nearly as smooth as regular 7018.
http://i487.photobucket.com/albums/rr235/mountainmolds/7018ac.jpg

The 7018AC did strike an arc effortlessly. It seemed to freeze faster than regular 7018, and I had no problem using it to fill 3/16" gaps, and no problem welding out of position. It seems to need more heat than regular 7018, and I eventually settled on 95 amps. Even at 95 amps, it still has a fast freeze, and that makes it challenging to get a smooth, consistent bead. When I use up this can, I will probably go back to regular 7018.

[MTNGUN]

The outside of the bucket got a root pass with the 3/32" 7018. Later, the outside will be capped with 5/32" 7018.

Meanwhile, I started welding the inside with 5/32" 7018. For the inside, I skipped the root pass. Dragging at 160 amps DC.
http://i487.photobucket.com/albums/rr235/mountainmolds/7018_5_32.jpg

While I was welding the inside, I noticed a crack.
http://i487.photobucket.com/albums/rr235/mountainmolds/crack_big_bucket.jpg

The crack was ground out.
http://i487.photobucket.com/albums/rr235/mountainmolds/crackbb_groove.jpg

The crack got a root pass with 1/8" 6011 at 95 amps, followed by a 5/32" 7018 cap at 160 amps, weaving a little.
http://i487.photobucket.com/albums/rr235/mountainmolds/crackbb_weld.jpg

There's another evening's welding left to do, but nothing too exciting, so that's probably all the photos for this project.

[Langanobob]

Thanks for posting this. Several years ago I built a smaller bucket for a mini-excavator and I think I heated the plate to bend it. But it was much smaller. I think I ran some hard facing rod over the heavy wear areas.

[mark61]

I started a job like that for a track hoe using 5/8" plate once. Tack, heat, bend and tack again. Never finished it cause the company owner found someone else to do my job for 10 cents an hour less........Also lined a bucket using the machine to push down while I tacked/ welded. That later developed stress cracks for cold forming or from bend lines I think since it did not bend smoothly.

mark61

[torker]

When I first saw this i realized it was too late... but...When I do a wrap over like that, I do it my way...
I cut the plate so it hangs out over the edges about 1" on either side.
Then wrap it over...weld inside and out and trim off the excess so there is about 3/8" hanging out the sides.
This gives far better wear characteristics and is much stronger because it is welded inside and out. The little bit of overhang also makes the corners last about two or three times as long.
It's also far quicker because you don't have the problem you had with the plate not lining up.
Also...I very seldom use a weave on a bucket. I always weld with stringers as it cuts down on stress tension and keeps the interpass temps down.
A lot of heavy weaves will yield a crack right beside the weld after time.
But...you've done a very nice job there and I'm sure it will last just fine.
Russ

[MTNGUN]

I cut the plate so it hangs out over the edges about 1" on either side. Then wrap it over..... It's also far quicker because you don't have the problem you had with the plate not lining up.
I considered that option, but in the end, I put the new skin between the sides, rather than wrapping over the sides, because that's how the old skin had been installed (and the old skin did not appear to be original, either). Also, there was an issue with the thickness of the sides at their outer edge. But, I agree that wrapping over the sides would have been simpler and provided some additional wear resistance at the corners.


.... is much stronger because it is welded inside and out.
My new skin is welded inside and out. The sides of the bucket are much thicker at the inside weld, whereas the sides taper rapidly to 1/8" on the outside corner, apparently due to years of wear. If I had only welded to the perimeter of the worn sides, the strength would have been limited by the 1/8" thick metal, no matter how good my welds were.

In other words, this bucket really needed a total rebuild, but for cost reasons, I only replaced the busted bottom.


I very seldom use a weave on a bucket. I always weld with stringers as it cuts down on stress tension and keeps the interpass temps down.
A lot of heavy weaves will yield a crack right beside the weld after time.
Hmmm ..... you know far more about welding than I do, Russ, but I'm having a hard time buying the weaves-are-evil theory. The Lincoln bible encourages the use of weaving with 7018. Every 7018 pipe weld I've ever seen used a woven cap. If weaves are so evil, why are they commonly used by pro welders and recommended by Lincoln ?


you've done a very nice job there and I'm sure it will last just fine.
The bucket really needed a total rebuild, not just a new bottom, but this is a homeowner bucket that only gets used a couple of times a year, so it'll probably outlast the owner. At least now the owner can use the bottom of the bucket for pushing fence posts without having to dodge the big holes in the bottom.

Thanks for your tips, Torker. I've learned a lot.

[Bob Ford]

Mtngun

Looking at your welds I think you might try a magnifying lens in your helmet.
I use a 2 makes the weld look larger and is easier to see what is happening.
http://www.millerwelds.com/products/weldinghelmets/parts.html

Bob

[torker]

You see weaves on pipe because it just sits there. A bucket gets the crap beat out of it and will crack beside a weave.
I have to rebuild big coal buckets to very strict codes. They do NOT EVER allow weaves. Ever....you weave on them...they send them back

[boslab]

Try this, french chalk, run your chalk along where the weld is intended to go, when you spark it up [and before if your glass is a low number] the chalk almost flouresces [spelt?] with uv, you just seem to see where your going better, even with an autolid.
regards
mark

[JMI]

You want a good 7018 rod go with Atom Arc (http://products.esabna.com/can/EN/home/filler_metals_catalog/filler_metals_product_detail/q/display_id.id4367f2a94f4fe5.88107142/category_id.257/path.filler_metals_covered_electrodes_carbon_low_a lloy_steel_low_hydrogen_atom_arc_7018_e7018). IMHO there is none better.

Jim

[Carm]

"Hmmm ..... you know far more about welding than I do, Russ, but I'm having a hard time buying the weaves-are-evil theory. The Lincoln bible encourages the use of weaving with 7018. Every 7018 pipe weld I've ever seen used a woven cap. "

You'll see woven pipe caps on low stress Gr.B pipe systems sometimes, but to my knowledge work under ASME IX has mandated stringers for over twenty years. Torker gives some reasons, there are others, grain refinement, shrinkage stress (visible as reduction of O.D.) and weld metal dilution/pickup.

[MTNGUN]

You see weaves on pipe because it just sits there. A bucket gets the crap beat out of it and will crack beside a weave.
I have to rebuild big coal buckets to very strict codes. They do NOT EVER allow weaves. Ever....you weave on them...they send them back
You have codes for buckets up there ? My goodness !

Pipes actually have serious dynamic forces to deal with, in addition to heating/cooling and expansion/contraction, and even seismic considerations. Not to mention, people can get killed or injured when a chemical or steam pipe fails.

Pressure vessels are highly regulated, but all the field welds I have seen on pressure vessels were capped with a 7018 weave.

In fact, in my jurisdiction, the only time you need a certified welder is for boiler piping or for pressure vessels. Boiler piping only as far as the main isolation valve, after that, no cert required. That's in the private sector -- government projects may be a different ball game.

I don't have access to ASME codes, but I'll review what the Lincoln bible has to say about weaving vs. stringers. So far the only thing I've found is not to weave too wide (generally no wider than the diameter of the electrode). Otherwise, the Lincoln bible shows page after page of 7018 welding procedures with a weave. So yes, I am puzzled ! ! ! ! ! I don't claim to have the answers, but it's fair to ask the question.

My first thought that maybe the buckets you are working on are made of AR or some other fancy alloy ? I've heard (on some of the welding and fabrication forums) welders mention the need to preheat when welding on buckets that are made of alloy. But mild steel ????? I don't think so.


Try this, french chalk, run your chalk along where the weld is intended to go, when you spark it up [and before if your glass is a low number] the chalk almost flourescesnt with uv, you just seem to see where your going better, even with an autolid.
I've never tried that, but I'd like to. Sometimes I do have a hard time seeing the intended path, and I've even been known to veer completely away from the joint. French chalk, is that generic welder's chalk ?


Looking at your welds I think you might try a magnifying lens in your helmet.
I use a 2 makes the weld look larger and is easier to see what is happening.
Yes, I do benefit from a magnifying lens. I'm currently using a 1X (or something like that) which helps, but I'd like more magnification. A 2X is on my shopping list.

Hey, Bob, that was not exactly a compliment. LOL ! ! ! If you were referring to the 7018AC weld, yes, that was a sorry bead, but my point was the AC rod was difficult to work with. Sure, a better man could make it look decent, but Joe Average like me would benefit from a smoother rod.

You guys are tough to please, but at least I am getting some constructive tips. Thanks for that !!!

[boslab]

I can see what torkers point about the HAZ, with the weave it will be wider and therefore less distinct and the seggrigation within the weld would be less distinct, or the weave will input less heat per sq mm or whatever, i'm unfortunate in that i learnt to weld working for a pipelaying company called Somerville years ago, root with celulouse rod [stovepipe weld] run, run etc cap with weave.
i need some education i think, good place to get it here is [yodaish]
mark

[Bob Ford]

Mtngun

Was not trying to run your weld down. Look at my jib crane thread, those welds would get me fired if I was still working. Just pointing out it is easier to see with magnification. Instead of French chalk. Go to a stationary store and look for a silver lead pencil. Draw a line with it and it shines like a small mirror.

Bob

[Carm]

"Go to a stationary store and look for a silver lead pencil. Draw a line with it and it shines like a small mirror."

Either silver or argent, depending on the maker. For fine layouts and lines that don't blow off when gas cutting, unbeatable.

[boslab]

Mtngun

Was not trying to run your weld down. Look at my jib crane thread, those welds would get me fired if I was still working. Just pointing out it is easier to see with magnification. Instead of French chalk. Go to a stationary store and look for a silver lead pencil. Draw a line with it and it shines like a small mirror.

Bob
good one, ill try that asap. thanks
mark

[MTNGUN]

Well, Torker's criticism of weaving was a shock to me, and I didn't take it very well.

But, as I have said on other threads, I was self taught, under some of the worst circumstances, and I know I have a lot of bad welding habits. Now that I can "play around" with welding at home, under more relaxed circumstances, I finally have the luxury of experimenting with different techniques, amps, etc.., and seeing how they compare. And getting intelligent feedback from better welders on these forums.

Though -- I'm still puzzled as to why weaving (or oscillating, whatever you want to call it), if it so evil, is still widely practiced, and is recommend by some authorities like the Lincoln bible ? And, how do you run 7018 out of position without some sort of oscillation ? I find that that oscillating the rod helps make the puddle "stick". But, I'll keep practicing. I may be an old dog, but I can learn the occasional new trick.

After I finished welding up the bucket last night, I practiced running stringers, with different heats and speeds. I have to admit, some of those stringers were looking a lot better than my typical weave.

I tried using a chalk line to guide the bead -- at first it worked, but eventually the line got coated with welding smog and was no longer easy to see. Silver art pencil, huh ?

I also made some progress with the 7018AC rod. After turning the heat up 5-10 amps higher than I would run regular 7018, and slowing the rod movement to a crawl, until the arc was on the verge of drowning in the encroaching puddle, the beads started looking just like regular 7018. If I get to the point where I feel I've got it licked, I'll post a little thread on 7018AC. There may be other buzz box users out there who would be curious to know more about the AC rods.

[Bob Ford]

I notice you have a fixed lens helmet. Have you tried a gold lens? I like a #9 for 3/32 and up to 1/8. If I am running lots of 1/8 more than 10 rods as fast as you can use them I then use a #10. Also try to keep the sun from behind you it reflects on the lens and makes it harder to see.

Bob

[MTNGUN]

I notice you have a fixed lens helmet. Have you tried a gold lens? I like a #9 for 3/32 and up to 1/8. If I am running lots of 1/8 more than 10 rods as fast as you can use them I then use a #10.
Bob

A gold lens is on my shopping list. I tried a gold when I first began welding, and didn't notice an improvement at the time, but that was 27 years ago.

I'm currently using a green #9, because most of my welding is small repair jobs with small rod, and I have a hard time seeing where I'm going. However, #9 is too bright with 5/32" rod. I've got a #10 and #11 laying around, but was too lazy to change the lens. Probably should get another helmet or two so I don't have to swap the lens.

Haven't tried the auto helmets yet. I don't feel the need for the auto feature, but an adjustable shade might be handy.

However, they say a fixed gold lens offers the clearest view, so that's what I will try next.

[Bob Ford]

I picked up a auto darkening helmet in HF about $50. My welding now is by myself and whatever interests me mostly less than 1/4. A mig does well for most. The auto dark works well for this use as you leave the hood down and can see to position the wire, fire up and the lens is dark before the flash. The cheap hood does give false darkening as it will trigger from sun and flashing, but it has never failed to darken when needed.

Bob

[torker]

MTNGUN...I had a guy drop by last nite with a Bobcat...I'll be gettin that job in a couple weeks. It's a perfect example why you shouldn't use a weave on equipment that takes a lot of abuse.
The boom developed a crack...then someone weaved in a repair...which pulled so hard that it busted the entire opposite side off.
Hang on now tho...I do use a weave the odd time if I think it is in a non stressed area.
Rule of thumb...it you are repairing a crack...don't weave it. It's obviously under stress and a weave will only induce more stress.
A lot of buckets I work on are built out of AR...or 425 and if you weave that stuff...it will crack right beside the weld almost guaranteed.

Yes...weaving is highly acceptable. Except in extreme stress situations....which is the life of earth moving equipment.
Russ

[MTNGUN]

Torker, I posted a question on weaving vs. stringing over on the Welding Web forum, to see if anyone else shared your anti-weave philosophy. Most people were skeptical, and didn't see what all the fuss was about.

But ...... one guy who used to work for a mining company had this to say:

When I used to weld on mining equipment we were not allowed to weave anything...ever under penalty of death. Those were the foreman's exact words. Weave and die. We were welding all AR plate though. Anything that got weaved got instantly rejected by the mine and we had to haul our mobile rig out there and fix it. Only had one guy ever weave anything that made it out of the shop. He got fired about 30 sec after he got back from fixing it. Heavy equipment people seem pretty hell bent on stringers so I'd go that route.

The reasoning being that slag can get trapped a lot easier and "pepper" if you are weaving wide enough for the puddle to solidify before you weave back to that edge. (that was the reason given to me) We had quite a few arguments about this subject since most people who worked there were or had been D1.1 certified for unlimited thickness. I personally, have never gotten certified in D1.1 though.

We weren't allowed to whip either for the same reason.
That helped me understand where you are coming from, Torker.

As to whether weaving causes more stress in mild steel, I will remain skeptical until someone provides a link with some authoritative data.

I will admit that it is easier to produce a clean, quality bead with a stringer than with a weave -- providing you are welding in a flat position that lends itself to running a stringer. I will try to use stringers more often for that reason alone.

[MTNGUN]

I picked up a auto darkening helmet in HF about $50. My welding now is by myself and whatever interests me mostly less than 1/4. A mig does well for most. The auto dark works well for this use as you leave the hood down and can see to position the wire, fire up and the lens is dark before the flash. The cheap hood does give false darkening as it will trigger from sun and flashing, but it has never failed to darken when needed.

Bob

How do you like the headgear in the HF helmet ?

The reason I ask is that I tend to be pretty hard on head gear, plus I seem to have an odd shaped head that helmets refuse to hang onto. Right now I have two cheap helmets and I'm constantly fiddling with and repairing/replacing the headgear. I was thinking to pick up a Fibre-Metal pipeliner helmet because they are supposed to have nice headgear, with an elastic band.

[torker]

All I can say is..."Thank God for the Weavers of the World!"
They provide me with a constant source of income.
Prolly 75% of the repairs I do to buckets and other equipment are due to heavy weaves causing stress to welded joints.
The best example I have is one shop where I do part time heavy bucket repairs.
Myself and the other old weldor there always use stringers. We very seldom have any cracking issues.
The younger impatient guy...he whips in weaves any chance he gets. The boss lets him get away with it because he only welds there once in awhile.
He is the reason I get called in so often...to repair the cracks he always gets from weaving.

It's so simple...far greater HAZ...a lot more pull from the heavier weld bead.
You have to understand how strong a weld can pull.
A big weave can deform 3/4" T425 steel like you can't believe.
I've seen over 100 feet of heavy Hydro dam penstock...20 foot sections welded together...pull out 1" thick welds like they where bandaids...and pull the whole pipe section out over 1" in that distance.
THAT constitutes a whale of a lot of energy.
I'll take pics of the mild steel on that Bobcat boom when it comes in and post them.
That one weave caused a 3/32" crack to split open all the way down the boom. It split a good weld right in half.
My background in bucket and other repairs is largely mining also.
These guys have some very well kept records and proceedures on what works and what doesn't. They also have some very savvy engineers who keep us on our toes.
I can honeslty say that I've never had a bucket returned with a crack that had anything to do with the way I weld them...all stringers...watch my interpass temps...proper fillet sizes...proper preheating and post heating.
But I'm hopin all the other guys keep right on weavin...it's very good for my wallet!
As for your lil backyard bucket and the smallish weaves you made...you will likely get away with them...it's not the end of the world.
But rememeber...buckets are always flexing and are always under great shock loads. This is why they fail and the piece of pipe resting in the dirt doesn't.
Russ

[Bob Ford]

I have used he Huntsman 411p for 30-40 years. They stay in place and are comfortable as a helmet can be. The 411Ps I have are light weight, not the heavy bucket I saw in your picture. The HF was bought mainly to see if a auto dark was useful. Before you buy carefully check the head band and adjustments, if you can not adjust for you don't buy. If it adjusts put it on then tilt you head to the side. If the window moves don't buy. I have been retired for 20 years so I am not up to date with all the new things.

Bob

[Bob Ford]

Torker

Makes sense to me. A stringer is quick and puts less heat in the metal. With stringers there is time between rods. A weave has more rod time in the weld and affects a wider area. When it cools and contracts there is more stress. A good welder tries to minimize stress or make it work for them.

Bob

[MTNGUN]

Cracking of mild steel is generally due to fatigue. My 20 year old snow plow is a good example of fatigued steel. Every year I have to weld up a dozen or so new cracks on the plow and its frame. The plow's OEM MIG stringers are especially prone to cracking. So far, all of my stick weld repairs have held up, however, new cracks keep popping up in new places. After a while, it becomes more cost effective to install new steel rather than continuing to repair old, fatigued steel.

The manufacturer of Hardox AR plate provides some detailed welding recommendations on their website. Document TS #47 called "Weld Defects" is particularly good. It's in PDF form, so I can't provide a direct link, but here's the starting point:
http://www.ssab.com/en/Media/Downloads/

They talk about things like

-- use dry low hydrogen rods

-- avoid starting and stopping the weld in corners

-- the joint gap must be neither too big nor too small

-- use a back-step welding technique for long joints

-- sometimes a little preheat is required (but only on thicker plates)

-- the bead should be convex

-- controlling the heat input (mainly to avoid annealing the hardened plate)

-- the bead should not be excessively wide relative to the depth

It doesn't directly address weaving vs. straight dragging. Sure, an extreme weave would violate the width-to-depth rule, but that still leaves us with moderate weaves, wagging no more than 1 or maybe 1.5 rod diameters.

Sure, a big weave has more heat input, but if the only goal was to minimize heat input, wouldn't they recommend 1/16" rod, or TIG ?

Torker, you have helped me see the advantages of straight dragging 7018, and I plan to use that technique more often in the future. But, if the need arises to use a modest weave, I'm OK with that, too.

[torker]

Oh hell...if that's all the weave we are talkin about then...ya...lots of times I do that "fudging" too. Sometimes you have to to get the right bead profile etc.
I was thinkin moe along the lines of a heavier weave.
What you are talking about is rod manipulation...fudging....to fill in one pass.
Ooops!
Russ