RE: exhaust manifold [was Re: Pietenpol-List: humped center sectio

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RE: exhaust manifold [was Re: Pietenpol-List: humped center sectio

Post by matronics »

Original Posted By: owner-pietenpol-list-server(at)matronics.com
et>For those contemplating stainless steel ehaust systems, let me share alittle pearl of wisdom that I learned just a bit too late:My original exhaust system on my Pietenpol was TIG welded stainless steel,welded by my neighbor (who also welded my aluminum fuel tank).- The weldslooked good, but after about 30 hours of operation, the left stack broke offand was only kept from departing the airplane by the SCAT hose on the heatmuff.- I had my neighbor re-weld it, with an additional strut to helpdistribute the load.- Then I flew the airplane to Brodhead and OSH (this wasin 2005).- On the way home, the right side stack broke off and was againheld in place by the SCAT hose.- I had to find a local welder make emergencyrepairs so I could make it home.I decided that stainless was simply not a good choice and made a whole newset from plain carbon steel, which I could weld myself.- No problem with it,except that it has begun to rust.- In another 10 years or so I'll have toreplace it.Meanwhile, I was talking to a fellow who makes exhaust systems for race cars(TIG welded stainless), telling him of my troubles.- He asked "What did youdo to shield the inside of the tubing?"I just looked at him with a stupid look on my face (fairly easy for me todo), and said "Huh?"He said, "TIG shields the area around the weld with argon gas to prevent theweld from burning, but with such thin walled material, the metal on theinside of the tube is just as hot as the outside.- You've got to shield itas well."He said that when he does a job like this, he plugs one end of the tube,then turns on the gas from the TIG torch and uses it to flood the entiretube with Argon.- He tests to see if he has enough by striking a match andinserting it into the tube.- If it doesn't go out immediately, he knows hedoesn't have enough Argon to shield the weld.So when it comes time to replace my exhaust system again, I may givestainless another try, using this technique.Jack PhillipsNX899JPRaleigh, NC-----Original Message-----
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RE: exhaust manifold [was Re: Pietenpol-List: humped center

Post by matronics »

Original Posted By: owner-pietenpol-list-server(at)matronics.com
>For those contemplating stainless steel ehaust systems, let me share alittle pearl of wisdom that I learned just a bit too late:My original exhaust system on my Pietenpol was TIG welded stainless steel,welded by my neighbor (who also welded my aluminum fuel tank). The weldslooked good, but after about 30 hours of operation, the left stack broke offand was only kept from departing the airplane by the SCAT hose on the heatmuff. I had my neighbor re-weld it, with an additional strut to helpdistribute the load. Then I flew the airplane to Brodhead and OSH (this wasin 2005). On the way home, the right side stack broke off and was againheld in place by the SCAT hose. I had to find a local welder make emergencyrepairs so I could make it home.I decided that stainless was simply not a good choice and made a whole newset from plain carbon steel, which I could weld myself. No problem with it,except that it has begun to rust. In another 10 years or so I'll have toreplace it.Meanwhile, I was talking to a fellow who makes exhaust systems for race cars(TIG welded stainless), telling him of my troubles. He asked "What did youdo to shield the inside of the tubing?"I just looked at him with a stupid look on my face (fairly easy for me todo), and said "Huh?"He said, "TIG shields the area around the weld with argon gas to prevent theweld from burning, but with such thin walled material, the metal on theinside of the tube is just as hot as the outside. You've got to shield itas well."He said that when he does a job like this, he plugs one end of the tube,then turns on the gas from the TIG torch and uses it to flood the entiretube with Argon. He tests to see if he has enough by striking a match andinserting it into the tube. If it doesn't go out immediately, he knows hedoesn't have enough Argon to shield the weld.So when it comes time to replace my exhaust system again, I may givestainless another try, using this technique.Jack PhillipsNX899JPRaleigh, NC-----Original Message-----
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Re: exhaust manifold [was Re: Pietenpol-List: humped center section]

Post by matronics »

Original Posted By: Ryan Mueller
Subject: Re: exhaust manifold [was Re: Pietenpol-List: humped center section]
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RE: exhaust manifold [was Re: Pietenpol-List: humped center section]

Post by matronics »

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Don't know - I haven't seen the procedure done, just heard his descriptionof it. I believe he said he plugged one end of the tube and flowed argoninto the other end for several seconds until it had displaced the air in thetube. He then checked the oxygen level by inserting a burning match.As Yogi Berra said "I've already told you more than I know".Jack PhillipsNX899JPRaleigh, NC _____
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RE: exhaust manifold [was Re: Pietenpol-List: humped center sectio

Post by matronics »

Original Posted By: owner-pietenpol-list-server(at)matronics.com [mailto:owner-pietenpol-lis
Actually=2C the repair on the way back from OSH was made by a professional welder=2C TIG welded. It lasted nearly twice as long as the first one (50 hours). It cracked too. At the weld.You=92ve confused me a bit ' in your 5th sentence you said =93you can weld 4130 without preheating or fear of cracking.=94 Then 3 sentences later you say =93With 4130 the area will need to be preheated to prevent cracking=94. Which is it?Anyway=2C to some extent I agree with you ' I like oxyacetylene welding. However=2C for some applications TIG is far better. I=92ve tried gas welding aluminum=2C I=92ll leave that for the pros. I also tried gas welding stainless and burned up a lot of test material without any good welds. MIG I have no experience with=2C but I know Champion Aircraft uses MIG to build Citabrias and Decathlons (at least the Citabria I helped rebuild had a lot of little twigs of welding rod stuck to it like MIG tends to leave behind).This was just a tip given o me that I passed along. I have not tried it=2C but it makes sense to me. Your mileage may vary.Jack PhillipsNX899JPRaleigh=2C NC
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> RE: exhaust manifold [was Re: Pietenpol-List: humped center sect

Post by matronics »

Original Posted By:> owner-pietenpol-list-server(at)matronics.com
> .net>> > For those contemplating stainless steel ehaust systems=2C let me share a> little pearl of wisdom that I learned just a bit too late:> > My original exhaust system on my Pietenpol was TIG welded stainless steel=2C> welded by my neighbor (who also welded my aluminum fuel tank). The welds> looked good=2C but after about 30 hours of operation=2C the left stack broke off> and was only kept from departing the airplane by the SCAT hose on the heat> muff. I had my neighbor re-weld it=2C with an additional strut to help> distribute the load. Then I flew the airplane to Brodhead and OSH (this was> in 2005). On the way home=2C the right side stack broke off and was again> held in place by the SCAT hose. I had to find a local welder make emergency> repairs so I could make it home.> > I decided that stainless was simply not a good choice and made a whole new> set from plain carbon steel=2C which I could weld myself. No problem with it=2C> except that it has begun to rust. In another 10 years or so I'll have to> replace it.> > Meanwhile=2C I was talking to a fellow who makes exhaust systems for race cars> (TIG welded stainless)=2C telling him of my troubles. He asked "What did you> do to shield the inside of the tubing?"> > I just looked at him with a stupid look on my face (fairly easy for me to> do)=2C and said "Huh?"> > He said=2C "TIG shields the area around the weld with argon gas to prevent the> weld from burning=2C but with such thin walled material=2C the metal on the> inside of the tube is just as hot as the outside. You've got to shield it> as well."> > He said that when he does a job like this=2C he plugs one end of the tube=2C> then turns on the gas from the TIG torch and uses it to flood the entire> tube with Argon. He tests to see if he has enough by striking a match and> inserting it into the tube. If it doesn't go out immediately=2C he knows he> doesn't have enough Argon to shield the weld.> > So when it comes time to replace my exhaust system again=2C I may give> stainless another try=2C using this technique.> > Jack Phillips> NX899JP> Raleigh=2C NC> > -----Original Message-----
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