Fixing Cracks in a Backhoe - Big ! with pics

[dfkrug]

Thx for thinking of us dialup folks, Rob. Actually they loaded
pretty quick, as I am usually getting 52K bps connection. It's
the 300-400K+ pix that I don't even try.....

Wow, those are some pix, John! Kinda like watching a train wreck.
Thx for posting...and nice looking repairs!

 

[john_bud]

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.

Presumptuousness?? Heck no! I'm glad you went to the trouble to explain it to me. I've wondered how people were able to do that. Then again, I haven't found the location for the "smiley faces" since the web page was updated! I'll be trying it with thumbnails in the future.

THANKS!
jb

 

[john_bud]

I did some frying on the cracks. DIdn't get finished, ran out of wire and have to change the spool. Thought it was a good time for a break.

Trying the clickable method -- here goes!








The 2nd from the last picture shows a crack. I knew it was there from when I was grinding, but the PT didn't show it. (what the ?).

I hope this is a better quality welding job than what was there previously!!

jb

P.S. Thanks to 3RRL for showing me how to add the smaller clickable pictures.

 

[3RRL]

I did some frying on the cracks. DIdn't get finished, ran out of wire and have to change the spool. Thought it was a good time for a break.

Trying the clickable method -- here goes!......

P.S. Thanks to 3RRL for showing me how to add the smaller clickable pictures.

No, thank you for using the thumbnails. Your pictures (and posting them) came out great! Excellent quality and clarity.
Hey, I thought you were supposed to be a novice welder?
Those beads you laid look pretty good. Looks like you got the heat (amps) right for some of that thick stuff you were on. Those welds are only about a hundred times better than your buddy (previous owner) did. hahaha
I don't know why the PT didn't show that one crack unless it was the one I saw in the 4th or 5th pic of the other batch of pictures?
Good work there John, thanks for sharing.

 

[thingy]

P.T.from what I could see,it looks like you are not wiping the dye off good enough,,its hard to get it all off,and impossible on rough welds,,but believe you can wipe it better. You gotta get all the red off you can after it soaks or it will hide what you are looking for.Also,you don't wanta do this when its real cold.
First,paint and rust and stuffs gotta be off area,than dampen a rag with solvent,and wipe.
Second,let that evaporate a few min,or it will fill crack.
Third,get you a little paint brush[makes it a lot neater] and spray dye on it,than brush it on area,brush it on area and about an inch on each side of where you are looking
Fourth,let that dye set and soak for 5-10 min,finer the crack you wanta see,the longer the soak time
Fifth,get you a clean dry rag and blot/wipe up most of the dye,than dampen a clean rag[not soaking],and wipe,,try to get ALL red off,,don't ever spray the solvent onto metal,you will wash it out of crack,,your goal is to remove all the red,but,most of the time that ain't possible
Sixth,let that dry for a min or so
Seventh,shake that developer can up real good,hold it about 12-18 inches away and spray light coats on,,like a women putting on hair spray,,,you want it a light white color,,but not runny or to thick,but you gotta get enough on to make it whitish and to soak that dye outta crack,,,thats what draws the dye out of crack,,if you do it right,[which is not done to often],you'll just see white,not much of a red background,,only thing you want red is cracks or holes.
Cracks of course will be longer than wider indications,,holes and slag inclusions will be more rounder,,,although they don't look good,a rounded indication is not much to worry about as compared to a crack,a rounded indictions generally will not spead,while a little crack will.
The way its used most often,is after cleaning area off,but before grinding,,sometimes grinding will seal a fine crack,you do a test to see what you got,,than grind,and retest,grind,and retest,,etc.
Most of those bigger cracks you got,,well,,guess there is no need to p.t. them first?! thingy

 

[thingy]

Just saw you last photos,,you got to let it soak,like I said above,and don't spray solvent on metal or wipe with a wringing wet rag,,its possible the grinding sealed it,,but not likely,,follow my above directions on dwell times,soak times and how to clean and dry,,and bet you if there is crack there,you will see it.......also,,the weld didn't look white to me,,did you put developer on it? You are supposed to be looking at a white surface,,that draws the red out,not shiny metal,,,,thingy[or maybe it was after you cleaned it?],,in any case,if you can see a crack with your eye,,you shouldn't have any trouble at all seeing it with p,t.,,,p.t. is meant to be used really,when you can't see it with your eye,so,,you must be doing something wrong,,follow them directions I wrote,,,,but for the most part,them directions are on the sides of the cans or any can I've seen anyways,,,thingy

 

[john_bud]

No new pictures or progress today. Spend 9 1/2 hours helping a buddy turn logs into boards on a band saw. 1/4 sawing wet oak is some heavy work! Due to space contraints, we had to muscle the logs onto the mill. No room for a tractor to help. My arms are sore!


Thingy,

From your directions (which are much more detailed than the ones on the can!!) it seems I did a couple a few things wrong. First I did the PT after grinding, probably sealing off the crack, then I sprayed the dye and got so much on that it was a real bear to clean off (didn't spray the cleaner on directly), and I think I didn't use enough fine coats of the developer. Good tip on putting the dye down with a brush. That would give better control. Like most things, you have to know what you are doing to get good results. Oh well, back to the shop for more practice. Hope I don't run out of cracks to check. Huh? What the heck am I thinking!!


3RRL - I AM a novice welder! but I did pay attention in the tech school class on welding and have been playing at welding for the past 15 years. I could be even better if I had taken the class sooner, it was only 2-3 years ago.

Now in comparison to the "expert" that did the welds I ground off, well no comparison is possible. (ha ha)

Anyway, I hope to get the parts in to the machine shop next week. I feel it's better to do all the hot work before the precision machining. No sense buggering up a new bushing with weld slag or warping it into a new and exciting shape.

jb

 

[thingy]

John,no,,,not likely,,,just said it was possible,,,to seal off crack by grinding. Thats the way to chase a crack,grind,than p.t.,,grind some more,than p.t. again...If you p.t. a visable crack,and you get no indication,,its something you did wrong in the p.t. process,,,probably washed the p.t. out of crack.
The goal in p.t. is to leave the red stuff in a possible crack,,get rid of all the p.t. thats out of crack,,than spray the white stuff on for background and to draw red dye out of possible crack. A visable crack [before p.t.] is a wide crack,which is easy to wash p.t. out of.
Also,they make water washable p.t.,,next time you get some,get some of that kind,,,,[it will say it on p.t. can],,,you don't need solvent to wash p.t. off,,,you just get you a water spray bottle,,and with water washable,you can even spray water,[out of your little spray bottle],directly on steel,,you can still use the solvent to first clean area to get any grease or oil off,,,easier to remove p.t. with water washable,,,not quite as sensative as solvent but works fine even for fine cracks.Do not clean water washable off with solvent.

Doing p.t. right takes some time,,,and you got to do it right,,its simple,,but still have to do it right,,if you just remember what you're trying to do,than it will help you do it right.P.T. is just an aid to your eyes. thingy

 

[EddieWalker]

John,

I just came across this thread and wanted to commend you on an amazing job. Working with heavy iron is very dificult. More so than most people realize!!!!

You have taken on a job that I thought was overwhelming, and it's way beyond my skills. But I'm sure enjoying your progress.

I am curious if you had any idea how bad it was before you started and if you had known what you know now, would you still have tackled it?

Thanks for al the great pictures and updates,
Eddie

 

[PBinWA]

Great work John! Thanks for sharing this project and getting the PT and trying it out and thanks to Thingy for tellin us how to use it.

Unless you're in the welding business a lot of the new stuff hasn't filtered out to us novices.

I picked some up today. Don't really have a use for it at the moment but I thought I'd keep it around.

PB