Fixing Cracks in a Backhoe - Big ! with pics

[JimR]

Have you tried just putting the torch to these areas to see if the slag will pop off?

 

[john_bud]

Not yet, I'm out of gas. O/Ac

jb

 

[thingy]

Scafing tip for torch,yeah they sell them in all shapes,,might work,,but seems like I used one[tried to use one would be better] a long time ago,and didn't like it much,,,but,maybe I just wasn't using it right,,,,I do know that carbon arc works pretty slick once you get the hang of it,,and if you do it right,alls you need to do is power brush gouge area before welding,,,course I'm talking stick welding,not mig,,you'll need a stick machine that puts out about 150-200 amps,in d.c.,,,but,like I said,think they make a different carbon rod for a.c.,,,but if you ain't got a stick machine but do have oxy/act torch,wouldn't cost much to give it a try,,,,thingy

 

[HomeBrew2]

Not yet, I'm out of gas. O/Ac jb

You might want to consider getting a propane adapter for your regulator fitting for these times when getting the Ac filled is inconvenient ... it's sure kept me working when I've run out ...

 

[john_bud]

Silly Harbor Freight!

I ordered a needle scaler that was supposed to be delivered on the 18th. The tracking page has shown the package to be "Data submitted to FedEx" since 10 hours after I placed the order. Well, on the 19th, I called and asked WTF? He he, seems the box was still on the frigg'n floor of the shipping dock. Ha Ha! Looks like we goofed. Oh boy!

New delivery date is the 24th.

Looks like it's still me and a chisel, hammer, punch and other assorted toys.

I did get pretty decent welds after the 3rd time grinding them out. I honestly don't know where the slag is coming from. At this point, my best guess is that space aliens with a sick sense of humor are using a teleporter to beam it into the melt pool.

jb

 

[thingy]

John,I musta not read the part that said what you are doing now,,your getting slag from old welds? or your getting slag from the base metal or what? You still mig welding,right? You working on the bucket or something else,something ain't sounding right...thingy

 

[john_bud]

John,I musta not read the part that said what you are doing now,,your getting slag from old welds? or your getting slag from the base metal or what? You still mig welding,right? You working on the bucket or something else,something ain't sounding right...thingy

Not sounding right? That's the understatement of the year!

I'm still Richarding around with the bucket. It looks like a liner patch was welded in by a person with a stick or flux core mig. They also replaced the cutting edge and added side cutters. The fit up was pretty good, just the knowledge of the most basic thing you do after using a welder was missing. (chip off the dern slag).

The welds looked ok when I bought it, but I found out that the "welds" were actually just pretty but stubborn slag on top of snitty welds. I have been grinding them out and rewelding, but where they are, there is a lap joint. I think that slag from the other side is migrating to the melt pool. I have to be less than agressive with the grinding as it is pretty easy to hit air and that makes it harder to weld.

A for example, today I ground out the welds from the side cutter on one edge. Using a 4 1/2 x 1/16 disc. I could cut into the weld both vertically and horizontally, cutting it off of the bucket. Then plunge the disc into the area between the side cutter and the bucket side. Well, the (cough cough) "welder" must have beveled back nicely and put down a good root pass, that I am having a hard time getting out. Cuz when I welded a nice fillet, in several spots out came grey ooze. It hardened up and could be chipped off. Real glassy looking and tough. My Milwaukee 4 1/2" grinder with an extra course 5" wire cup doesn't take off the slag. I have been using an air hammer with a rounded point to get it off. The needle scaler would be helpful. When I get the ooze, it's back with the grinder and then reweld. There were only a couple spots on the side cutters that oozed after the first go round. No ooze on the 2nd round. Worst was the bucket liner which had 3 rounds of ooze in places.


To try and get any slag to show itself, the power has been turned up on the MIG. It's running at 399 IPM and 25.0V rather than the 24.0 that would be normally used. It spatters more, but is getting hotter. The joints are being pre-heated too, but only with a propane torch.

Funny thing is that this bucket was used a lot by the previous owner (who welded it) and the welds never broke or cracked that I have been able to see. The teeth he put on fell off, but the bucket looked ok. Even with use, the slag stayed on in most places. Any idea what was used?

jb

 

[thingy]

John,sounds educational,,grey oooz,,must be trapped whatever in between plates?flux core sometimes is pretty hard to get slag off once it cools,,,figured it was on the bucket,just couldn't figure out where all this trapped slag you was talking about was coming from,sounds worse than just some slag,,,air arc,,,would be of real help to you here,[well],if you had a stick machine,,Yeah you must be scottish or something,,sometimes things just get so wore out that they are actually useless,,you can fix anything,,but,,I do alot of richarding around,,,but seldom do I do johning around,,will work on junk if I have to,but if I don't,I won't,,,,thingy

 

[john_bud]

Here are some pics of the creaping ooze.

Starting with a grind on a weld that looked solid

Next spot over

It is getting better, slowly. But --> This isn't making me a fan of stick welding nor of flux core MIG welding. That's fer sure! At least a snitty MIG weld looks like a snitty weld!

jb

 

[schmism]

<cough> TIG <cough>

can you OA weld stuff this big? i mean either method works by just heating the surface/area to a point that it starts to melt.... would not the hot intense heat draw it up like what your doing with the MIG, just avoiding the weld/grind/weld/grind over and over because the constat addtion of filler you have ot then grind back out?