The Worst Casting I Have EVER Welded

this is a transfer case cover for a suzuki samurai and it has suffered a pretty standard crack in a pretty standard place due to a pretty standard gear change that's about as typical as it gets but these things are getting harder and harder to find which is why a weld is going to be the repair for this one now the weld procedure is also pretty standard which is why i took the social media before taking this on to see if anybody was actually even interested in a pretty standard repair because well i wasn't gonna bother making the video about it but you guys said yes and as it turns out this repair was anything but standard as it is the dirtiest casting i have ever worked with and i almost walked away from it completely now how i managed to take the control back on this part and successfully finish it and repair it that's a secret i'm going to share with you guys so to start this off we need to get it cleaned and find the end of the crack the cleaner i'm using is a product called crud cutter which is general purpose cleaner that does wonders on removing oil it's water soluble and non-harmful and this episode is not sponsored by them in any way i just happen to use this stuff now it is important to find the end of the crack so that we can terminate it thus keeping it from cracking further or propagating the best way to find out where the crack ends is to heat it up heating causes expansion of the crack as well as makes the trapped oil seep out of the crack which is an added cleaning bonus now with the crack heated up i can see where it will propagate to if we don't terminate it this can be done with a very small hole drilled just past the point where i can see the end of the crack i decided to mark and drill both sides as it appeared to terminate in two different places and it doesn't hurt a thing if we add a little extra weld and now it's on to the grooving a carbide bird tool in my die grinder will cut the groove out of the crack which is necessary to ensure we achieve proper penetration with fresh metal throughout the crack which translates to more strength the width of the groove is roughly a quarter inch or about six millimeters the depth of it was left relatively shallow on purpose because there is another problem that we have to address when the casting is cracked it distorted the part which occasionally happens but in order to understand why this is a factor we have to consider you have to understand how metal is usually cut on a shear or tin snips for example you get a near perfect straight edge there is a small fracture area but it's virtually impossible to stick the two of them back together in a repeatable position when a part cracks it almost never comes out completely straight or with a perfect smooth cut line instead it fractures leaving several surfaces which form a mechanical lock when pushed back together think of it as kind of a natural position memory if you will so if we take all the surfaces away with the groove the mechanical lock will be removed and the part may not align properly when the repair is completed so with all the grooves created and the part rinsed off for the final time i clamped it down to the table to restore the flatness in correct position now welding cast aluminum is tricky for a handful of reasons the first is that the metal itself is about the consistency of a metallic sponge meaning there are several pores contained in the metal that often combine to create bubbles the lesser quality castings usually have residual particles from the casting itself or even from the metal that was used now those particles combined with the pockets of air create a very annoying byproduct which we often call junk in order to make a weld stick to the part we have to displace the junk first before replacing it with new fresh metal the standard procedure to displace the junk is to simply run the torch over the top of the joint to create a pool what you're effectively doing is melting it down pushing everything out or purging all of it out to create a nice thick fresh layer to weld to you've got to recast that layer and this is exactly where the standard job took a swan dive right down into the hell that it became i mentioned earlier that this is the dirtiest casting i had done in some time it's actually dirtier than nissan and toyota castings which have plagued welders for years it really didn't take long for me to figure this out too because as soon as that molten pool started to form a gigantic junk hole would appear or even several of them would appear at once this isn't super uncommon but it was getting worse and worse as i went along it got so bad at one point that the junk contained inside the casting was displacing my shielding gas which caused the aluminum to fight back this is seen here where the aluminum instead of staying molten created its own natural defense forming its oxide layer there are even a few other times where the junk would out gas so violently that it would just spoil the tungsten flat out now i knew this was only going to get worse if i kept chasing out the holes so the second trick i often employ on dirty castings is to physically displace the junk by forcing it out with fresh molten aluminum the idea behind this is that the fresh giant pool of molten aluminum is at the ready to fall into the junk cavity because it has more weight than the air the trade-off is that it doesn't always allow particles to escape from the casting and you often have less control over the size of your bead profile nine times out of ten it's gonna be much much larger now it was working well for just a little bit but this casting is a disaster altogether you can often see particles and sparks flying off of a cast part when you weld it but this is just a bit much here i mean come on every completed push of the filler in one spot to displace one section of junk meant that another one would open up right next to it chasing it only makes it worse and i very stubbornly kept chasing it until i finally just walked away i was literally seconds away from contacting the customer and saying this piece is fubar looks like you're going to have to go find something else but then i remembered something the decision to very stubbornly and frustratingly chase the junk out meant that i was making the weld pool wider and every time i tried to just put more filler in there to displace it only made it worse because i kept increasing the size of the molten area which only meant more junk would surface it was a completely uncontrollable perpetuating pile of junk experience is often the only way you will figure out how to handle tough situations like this so if you're getting your butt kicked by a part like i was walk away and clear your head for a bit there is literally nothing more expensive than a part made or repaired during a moment of frustration when you don't have a clear head taking the time to walk away made me think about it and i realized that since this was such a dirty casting that it would be best to consolidate the weld pool and profile which basically means run several passes much smaller until that can be filled back in and repaired so instead of one massive bead i kept it much tighter and i tied in several smaller beasts to create one big one this will keep the junk displacement more controllable which allows for a stronger overall weld to be laid in now i do have some reservation as to how well this is going to hold up over the course of time especially knowing what caused the crack to begin with add to that the discovery of how disgustingly dirty this casting is i decided not to charge the customer because it's probably just going to crack again so if you can do me a solid and smash that like button to spread this video around you'll not only be helping other people out in the future when they encounter a similar situation but i might get a couple bucks back on the labor so please and thank you now that's all i got for this round i'd like to thank you guys for watching as always i'll see you on the next episode you

Channel: The Fabrication Series

Views: 561,519

Rating: 4.9487057 out of 5

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Id: OWG1f5e7HEU

Length: 7min 40sec (460 seconds)

Published: Wed May 26 2021