The way i weld cast iron without fancy welding rod is, torch everything till its like 250 to 300 degrees. Tig it with 316L filler wire. Continue to torch the rest of the material to maintain heat in the entire piece. Quickly wrap the whole piece in fiberglass welding blanket to trap heat in. Let it cool very slowly. I have had very good luck doing it this way with no come back repairs yet. Ive done this on stock manifolds and turbo cast manifolds. The ping you hear is the cast cracking from rapid heating and cooling. So trick is, to try and mantain the same heat for as long as you can with equally distributed slow cooling. And ... at end of day, cast is crap to weld, good luck
I used to do similar but with SS 312 rods (these rods are made for welding difficult alloyed steels, it's strong and very ductile 20%) or more difficult to find nickel rods and simply a small inverter stick welder. The piece is prepared (holes, grooves, etc), heated to 250 to 300 degrees Celsius, on hot iron the 312 melts like butter with a mere 40-60 amps for a 2.4 mm rod, I make first several "stitch" welds spaced of 2 cm and 3 cm wide ACROSS the crack, so the crack cannot further open nor "move". That permits also to relieve the welding stresses over a large surface, so the stresses are not concentrated only in the central weld of the crack. Immediately after the stitches, I begin to make the welds on the grooved crack by small lengths of 2 cm starting from the ends of the crack and alternating sides so the crack is welded from the ends to the center. You have to keep an eye on the temperature of the cast iron, it must stay around the 250-300 degrees great max, so you may need short cooling periods. No pinning necessary. The job done cover well and let it cool very slowly. The "glass" of the weld will peel alone when cooled. The advantage of the 312 is that it melts and grips so easily that you heat very little the piece, it's as easy as applying hot glue. I have repaired hundreds of cast iron pieces with very few failures. Bronze brazing with TIG AC does also pretty well but the strongest is the 312.
I've repaired a lot of cast in my career. I've had good results with high nickel rod and also silicone bronze. What I found works best for me is a good preheat of the entire piece (or as much as possible) and controlled cool down period, usually wrapping it all in welding blankets if possible. Clean, clean, clean beforehand, cast metals are somewhat dirty by nature and seem to fight you every step of the process. In the case of engine blocks, transmission cases ect, I usually use a torch and bring the temp around the cracks to aprox 160-175 degrees for a time to sweat out oils which also contaminate the welds. Just a few thoughts, nice repair.
Seems like best method is no preheating tigging aluminium bronze.or silicon bronze tig wire.brazing not fusing.stainless is shit your trying to fuse it to the cast instant cracking all that carbon making the join hard asf Some good vids on tigging with aluminium bronze or silicon bronze.aluminium bronze would be my choice.
You forgot the preheating. Forgot hammering. Forgot heating on oven. And you cut the pipe and use mild steel filler: you shouldn't cut and make space and you should use good and fit filler rod.
I can sympathize. Cleaning it better and then preheating it a lot more with a torch and then letting it cool very slowly over a day can help for next time.
Preheat and post weld cooling are essential to successful repairs on cast iron items. I also recommend brazing over welding and especially using the lower melting point braze fillers. This has to do with the time temperature transformations that occur in cast iron as it is heated and cooled. I would go into more details but it is a lengthy subject. I recommend looking up metallurgical references on cast irons for more information.
@@gtxmiata The major obstacle in successful cast iron repairs is the lack of ductility of the cast iron. This one of the reasons why nickel filler rods are recommended and the use of copper based brazing rods. I have found good success in many cast iron repairs by using high silver content brazing rods. hth
you can CLEARLY SEE ITS CRACKED right at 3:19, there is a crack on the 4th and 5th "dime from the right in the middle.... you clearly have no tig skills and you have no clue how to fix cast.
@@RageKage1776 he clearly stated that there was no cracks... there is plenty of info on the internet how to try and repair cast and even in all the 101 welding handbooks i have they all cover cast as having to be preheated and cooled SLOWLY and some times hammer welding works. besides that there are a ton of videos and online resources on how to repair cast. He did this for a customer and charged them $... that is so wrong its crazy.
