Wheres the end of the crack?

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I have a Caterpiller 3406 oil pan that someone hit a little too hard. As it always seems its kinda spider webbed. I got it slightly warm to find the cracks ends to drill them out. Put a groove with the carbide bit and then a ss brush. I welded , starting at the hole moving in. Flipped it over and the crack grew about a 1/4". I repeated....and again. Is there a better way to find the end?
Reply:not really,( hard to figure which way it will go )  i have chased a few cracksunless you preheat. or cut out an replaceidealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:spray the inside with some "spot check" penetrating  dye & give it a few minutes.  drill your holes 1/4" beyond the end of the crack that shows up.  Clean it really good afterward & weld er' up.Buy American, or don't whine when you end up on the bread line.
Reply:I patch and weld all around
Reply:Originally Posted by Fat BastardI patch and weld all around
Reply:Liquid penetrant testing is the best way to do it.  Relatively easy and something most shops should have on hand for things like this.  In the most basic form you need solvent, penetrant and developer.  Clean the part REAL good first and apply a light coat of penetrant.  Let dwell for 5-7min for most applications and then apply solvent to a rag and wipe it off.  You must make sure to clean every nook you possibly can with the solvent or the results will be impossible to read.  Then spray on a coat of the developer and wait a few minutes for inspection.Have we all gone mad?
Reply:sometimes you just have to take a rosebud and chase the cracks till they get tired of cracking.    otherwise the dye chem check is the only way.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Well I just watched the "Master" (castweld) work his magic this morning and if I had to guess he'd say prep / preheat / weld / postheat / slow cool.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:I had a 7/16" thick 304 stainless tank trailer in here the other day with a series of cracks all in a 12" square patch on the belly.  I've learned not to screw around chasing the cracks on these since they always come back, so I cut out a section larger than the cracked area and added a patch.  100% x-ray, double bevel, TIG, flat inside, overhead outside./None of my guys want to drill through 7/16" stainless with a hand drill and I don't want to pay for the bits, so it works out better.
Reply:I see...says the blind squirrel
Reply:dp is good but there is allways mt too simple and fastAfter the arc has died the weld remains
Reply:Originally Posted by Boilermaker237dp is good but there is allways mt too simple and fast
Reply:MT is nice, but requires more expensive equipment and more training,Have we all gone mad?