Fixing Cracks in a Backhoe - Big ! with pics

   / Fixing Cracks in a Backhoe - Big ! with pics #11  
From the looks some of those pieces would be easier to build new than try and fix!:D

Too many patches on patches to be sure of anything.:confused:
 
   / Fixing Cracks in a Backhoe - Big ! with pics #12  
John,
Very interesting and informative post. Great photos too.
Looks to me you have that MIG all figured out. Then on the other hand, LOL ... anything you did would have been better than the geek who owned it before.;)
Great job wrestling with that bad boy and fixing it up.
 
   / Fixing Cracks in a Backhoe - Big ! with pics
  • Thread Starter
#13  
Thanks for the kind words.

Thingy, I will be getting some penetrant. In the past I have uses a sharpie to highlight the cracks. Then wipe off with a rag dampened with acetone. Sort of worked. It will be fun trying it with the real deal. However, I will probably spend some more time frying on Sunday while the family is off at church.

Egon, If I took off all the patches all there would be left is rust and grease! I'll add a few snaps of the swing post. There is a replacement that will be swapped in, once you see the original it's obvious why...

Spyderlk, I have had my eye on a needle de-scaler. Any thoughts on the one from (Ahem) Harbor Freight? It's about $65. Worth anything or save up and get a "real one"? Also, I would LOVE to be able to Vee both sides, flat weld from both sides and grind back down. But, many of the real nasty spots are so deep that it's hard to even see where the sparks are while welding. I haven't posted those yet as the welding is, uh well let's just say, a bit lower in quality. Ha ha! A couple spots I had to weld by feel and hope it was in the right area. (wasn't) Then had to go back and fix it up. Those are still a work in progress...

In June of this year, the swing post was in a bad way. Cracks with daylight went across the top below the top pivot thru nearly the whole post. Only a section about 3" long was solid. That wasn't the only areas that needed some hot love. This was intended as a patch to get thru until winter (now). Interestingly, the patches held up. Even though they were really crappppy welds. Done out of position, while on the hoe. The cracks were spitting fire even though everything was pressure washed, degreased, sprayed with brake cleaner and heated with a rose bud. You can see the porous welds in some of the pictures. Most were welded, ground, cleaned, v-grooved and welded again. Some were on 3 or 4 cycles of that. It was not perfect, but at least there was no slag in the metal!

Original swing post top bushing area in June 06
topleftpivot.jpg


Same area December 06 - This was not patched by me!
P1020016.jpg


Top down view of same area
P1020020.jpg


Left upper side - I found at least 6 (six) separate cracks under that junk
leftupperclosepre-grind.jpg


Still cracked - but the cracks didn't grow over the summer. (lucky)
CIMG0535.jpg


Bottom left side
bottomleftsidepre-grind.jpg


After grinding and v-grooving the cracks
bottomleftpostgrind.jpg


After welding - and grinding - it was v-grooved and welded several more times.
bottomleftpostweldandgrind-oilcause.jpg


Bottom right
bottomrightpostgrind.jpg



Take a close look, the metal to the left of the v-grooves is the only non-cracked metal that was holding the post from falling in two pieces.
Rightsidereartoppostgrinding-.jpg



Boom cylinder attachment
P1020019.jpg


Bottom view - Now that's some quality welding...NOT!
P1020018.jpg



Original next to replacement. We added a plate on the back as there were serious cracks at each of the 6 corners that you can see on the replacement.
P1010021.jpg


P1010022.jpg


jb
 
   / Fixing Cracks in a Backhoe - Big ! with pics #14  
Well,maybe not better than new?? but,,better,,yeah,the red dye,,,if you put two cans on,you'd only be able to wipe up one can,the other can would still be in the cracks,good pictures,just a question of time,you get done with this and you'll be able to open up a shop. thingy
 
   / Fixing Cracks in a Backhoe - Big ! with pics #15  
Now, on the picture where you said "Now that's some quality welding...NOT!", I have to agree with you. I really am not sure I've seen a worse looking weld job. :eek: Obviously no reflection on you, just an observation that agrees with your observation. Are you sure he didn't just put some bird seed on top of that and let some birds do that job? :D

Good job with your repairs. Have you set any grease on fire yet? The last time I was welding on a BH for a guy, I had some really thick and hard grease get hot and runny. The melting grease made a line right to the spot I was welding. The next thing I knew I was smelling something burning. Ick! My natural instinct was to just raise my hood and blow a little on it to put it out. That didn't work, so I then thought I'd just pat it with my gloved hand to smother it. Then I had my glove on fire along with the BH. :eek: Oh well, he needed to repaint it anyway. :)
 
   / Fixing Cracks in a Backhoe - Big ! with pics #16  
jb, This BH has seen a lot of neglect and band aiding. Basically it looks as if repairs were always too little too late. You have a formidable job to do it right at this juncture. I believe a needle scaler and flap disk grind wheels would aid you in this. The HF scaler is the only one I have experience with and it does well at 20% the cost of name brands. I dont know how much better they may work - - probably essentially the same, but longer. Mine has broken twice in the 15yrs Ive had it. I havnt fixed it the second time because Ive a needle attachment accessory for an air hammer that works fine in a pinch. Ill have to order the repair part so I can have them both. Also, this time I will look hard at the part in an attempt to find out why it breaks. Probably a stress riser at a sharp corner edge causing a crack to start. With the immediate affordability of the price I wouldnt hesitate to get one. Use of it to clean, strain relieve, and leave edges and surfaces under compression makes for durable repairs. Ditto a flap disk for blending to spread out stiffness transitions before the last peening.

I may be observing in error, but it looks as tho some of your v's are very shallow. Have you gone to the root of the crack? - - or a little beyond, if possible? Would stick arc give you better access in some of the tight places?
Good luck.
Larry
 
   / Fixing Cracks in a Backhoe - Big ! with pics
  • Thread Starter
#17  
Dargo, Yup, it does look like fossilized bird dookie. Grease fires? Hmmm, only about a dozen or so. Real small though. That's why I spent about 2 hours with a pressure washer, a stiff brush and some purple degreaser. Then a lot of scrapping. Still get some pockets of fire from the oddest of places.

Spyderlk, Sigh... yeah the old girl has had a rough life. A neighbor has helped me with it a time or two. He thinks it had a high speed meeting with an overpass. Possibly right, but who knows?

You have mentioned the flap disk, why it over a solid disk? Choice of grit? I use the solid and get a LOT more life out of them. But, if there is a better way -- by all means -- let me know!

Shallow V's? Some are. I hope most are OK. It's a balancing act between shallow and out the bottom. It's easier to jack up the current or voltage and put down more metal than it is to weld across a 3/16 th gap. At least for me anyway. Even with shallow V's, I have to dance across some of the V and into the thicker metal to avoid burning thru.

I have only limited experience with stick, but I doubt that it would be head & shoulders better. In some areas it would be worse as the arc may want to flare out the side of the stick --- then again, with my limited experience ...

I started on the bottom of the Boom this morning. Here's some pics of the "as found" and "cleaned". I started to clean off the old bird dookie, got a lot of slag that should have been chipped out 20+ years ago. Then took a chip in the eye and decided to come if for lunch! (Yeah, I'm a wimp....)

PC240001.jpg


PC240002.jpg


PC240003.jpg


PC240004.jpg


PC240005.jpg


PC240006.jpg


PC240007.jpg


PC240008.jpg


PC240009.jpg


PC240010.jpg


PC240011.jpg


PC240012.jpg


PC240013.jpg


PC240014.jpg


PC240015.jpg


PC240016.jpg


I may wait to fry this up until I get the P.T. supplies in. Would be interesting to see how much more I am able to see.

Merry Christmas All!

jb
 
   / Fixing Cracks in a Backhoe - Big ! with pics #18  
jb, The flap disk would be in addition to, not instead of the hard disk. They would only be used for the last little bit of finish grinding. They have a soft aspect and it will be easy to blend. In this manner they last a long time. I recommend 40 and 60 grit.
Larry
 
   / Fixing Cracks in a Backhoe - Big ! with pics
  • Thread Starter
#19  
Ok, I have held off on doing any welding on the boom until I got a Dye Penetrant Test. Well, I had to go to 3 places but now I have it. And I must say, it is harder to use than I expected and gives worse indication that I anticipated. BUT, it is probably due to "operator error". Anybody with experience doing them PLEASE tell me what the best way of using it is!

Here are some pictures. I spent a bit of time grinding over the holiday and then sprayed the penetrant today.

Grinding discs used up.
PC250003.jpg


Still have more grinding to do. And YES, that is slag in the weld. I have changed my mind, I no longer want to kick the previous welder in the butt, I want him to turn around first!
PC250005.jpg


Penetrant sprayed
PC260002.jpg


Developer sprayed after wiping off wiht the cleaner
PC260003.jpg


PC260004.jpg

PC260008.jpg

PC260009.jpg


So, what did I do wrong? and or how can I do it better?

jb
 
   / Fixing Cracks in a Backhoe - Big ! with pics #20  
John,
I'm no expert but it looks like you did it right. The penetrant is supposed to reveal cracks and it will show up darker in those places as it gathers there. An example would be in your 4th and 5th pics in your last post (from top down).
There appears a darker line that may be a crack, but looking at your photos, they are most likely weld overlap? A real crack would show up like crazy. Try spraying a crack you know exists for sure and you'll be able to tell the difference.

BTW, your pics are great. Super clarity and detail.
I noticed you use Photobucket as a host. As a suggestion, for the sake of the dial up guys, you want to post them as thumbnails so they can click on them and let them load up while they are reading /viewing the rest of the post. Otherwise the thread takes a long time to load up for them. If you are interested in posting thumbnails, this is how you can do it.

Go to your Photobucket account where your photos are. They are shown in thumbnails, right?
Underneath the photo in front of the photo name is a square box you can check.....check it.
You can check more than one photo if you want.
Then scroll all the way down to the bottom of the page.
There is a rectangular box that says "Generate HTML and IMG code" .... click that.
A new page will pop up and you will want to highlight the 3rd rectangle down that says "IMG clickable thumbnails for message boards - recommended"
Then right mouse click and copy all that text in that rectangle.
Open up TBN to your post and paste all that text into your post.
I usually have TBN and Photobucket open so I can work between them.
When you "preview" your post, the photo should appear as a clickable thumbnail.
Then you can submit your post and the photo should come out like this example.



John, please excuse my presumptuousness about you not knowing how to do this.
If you already know ...I'm sorry and just ignore the Photobucket part of my post.
 

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