large cast iron exhaust manifold repair

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heat to 1100, OA spray weld, post heat 1100, cool down 100 degrees per half hour, grind excess weld, presure test, use needle scaler to give texture on non machined surfaces, stand in front of fan (me) between welds- its a hot job!Peter Attached Images
Reply:Nice work!Welcome to the forum.Rex
Reply:Is that from a bakery oven or a kiln?Good job.A butterfly without wings, is just an ugly bug
Reply:Nice weld..this may not be the right spot to ask about how spray welding is done, but ask those that have done so us that havent can learn..what equipment and what is the proccess??? Thanyou for any info..Bob
Reply:Originally Posted by roadkillbobbNice weld..this may not be the right spot to ask about how spray welding is done, but ask those that have done so us that havent can learn..what equipment and what is the proccess??? Thanyou for any info..Bob
Reply:thankyou for the reply..looks like that could be usefull in many aplications..well another toy on the xmas wish list....
Reply:Nice work.Working with cast myself, mind you not to that extent, I can appreciate the amount of work that went into that repair.....Mike
Reply:The above exhaust is an elbow to connect the exhaust port of a cylinder head to the exhaust manifold. It is off an large engine that drives a compressor. The compressor is to push natural gas downstream in a pipeline. I didnt ask make of engine it came off of, but I was told each cylinder has its own elbow. With a port size of 8x12 inches my guess is its quite large! The elbow weighed about 200lbs.
Reply:Man, that's neat.  Sounds expensive, and tricky."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Is that a gas-fired unit for preheating, and if so, do you have to shut it off while spraying?I can just feel the heat  radiating from the manifold when you open the oven cover. What grade lenses do you use while working? Why no pictures of the 'pretty  color' it gets when hot; don't chance ruining the camera, or just not enough hands? . .
Reply:Yes its a nasty (natural gas)  unit, 1,000,000 btu main burner and 250,000 afterburner. Afterburner is for heating oily parts, it burns smoke and fumes. Main burner is forced air, you can't get close while on!Gas welding-shade 5. No pics while welding because too much is going on! Two pair knit kevlar gloves under w/ kevlar loop wool lined gloves, fire suit, head gear while welding. Casting looses 200 degrees in 5 min with door open, then close and bring temp back up. Sometimes I get too hot to last 5 mins welding. 2 inch high pressure gas line to feed this beast, the utilities people love me.Peter
Reply:Originally Posted by paweldorIt's a specialty torch used with O/A.  Has a receptacle for inserting a bottly of powdered metal above the torch handle.  Heat you repair area to the desired temp, depress lever (like a cutting torch would have) and powder enters the flame stream, becomes molten and bonds/fuses with the base metal.  Various powders for various applications.  This is called "Hot Spray" as base metal is heated up rather high.  There is also a "Cold Spray" used mainly for shaft or bearing surface build up in machine shops.  Base metal is not heated to such high temps to prevent shaft warpage.  Temp controlled by cool air blowing on back of shaft, or, removing your spray torch, or both.  Temperature indicating crayons are a must when cold spraying.  Below is a Eutectic brand of a Hot Spray setup listed on ebay.
Reply:That's a good deal, bottles of nickel 99 powder are expensive.  I've seen metal spray done once before in a demo, I was impressed.  You have really got to be able to read the temperature of the steel, though.
Reply:Originally Posted by 76GMC1500That's a good deal, bottles of nickel 99 powder are expensive.  I've seen metal spray done once before in a demo, I was impressed.  You have really got to be able to read the temperature of the steel, though.
Reply:I did hot spray in college on a chevy exhaust manifold. Never got really good at it. Unless you do it a lot....I can't imagine that you practice much. After hearing your description of the heat you endure...not sure I would WANT to do it much!Nice job! Looks like you have that process completely under control. Another process we don't see much. I think it's cool we have this forum to see it.Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain