Analysis of a stainless weld and issue

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Hello,I joined the forum because I am not a welding expert by any means and I need an experts opinion.I am a brewer, and had a local shop do some welding on 18-gauge 304SS stock pots. They were just welding in a variety of full and half couplings.Just to preface: I specifically asked or restaurant quality welding experience because after all the product will be consumed. Much of what is below is the post I made on some online brewing forums. I received a lot of great replies but I am hoping to seek more specific replies. I know sometimes it's hard to judge from a picture.I have to determine if the problem is correctable is or not and if so, how? I also have to determine if there is anything unsafe and that may result in a premature or relatively near-term failure. Without further adieu - the post and some pictures and I thank you in advance for any replies.------------------I had a local welder weld some fittings into new 100 quart update international pots. The first contact with water was when I was passivating them early October. I used about a 3% concentration of nitric/phosphoric acid. - Loeffler KMS-10 which is formulated for this. I noticed almost immediately after finishing the passivation and flushing that every weld, particularly where ground, was developing what appeared to be rust. When I got home I tried to scrub the heck out of all the areas with Barkeeper's Friend. At first this seemed to work. But I'd come back the next day, and the rust would be right back. So after some reading, I found out the most likely scenario is that they introduced steel somewhere along the lines. Probably the grinding wheel - or maybe a brush. I also read the only way to fix this is chemically - that no amount of mechanical treatment will solve it. So I decided to run KMS-10 straight - which is basically around 40% phosphoric acid, and 15% nitric acid. All the reading suggested this combination should take care of removing the iron. So I decided to do a test soak - I soaked it for about 50 minutes. At first it was very promising - I saw no signs of rust. But after I got all the acid out and flushed it well, about 5 minutes and this is what I saw:If my eyes aren't deceiving me, I see pit corrosion. And not to mention it took almost no time for the rusting to start again. Anyone else agree with this? Any other comments on anything else I can try? At this point I'm close to throwing in the towel and calling the pots unusable. Just to reiterate - the pots have never been used!Here is the before:Thanks in advance.------------------Last edited by jcaudill; 11-07-2012 at 07:37 AM.
Reply:Originally Posted by jcaudillHello,I joined the forum because I am not a welding expert by any means and I need an experts opinion.I am a brewer, and had a local shop do some welding on 18-gauge 304SS stock pots. They were just welding in a variety of full and half couplings.Just to preface: I specifically asked or restaurant quality welding experience because after all the product will be consumed. Much of what is below is the post I made on some online brewing forums. I received a lot of great replies but I am hoping to seek more specific replies. I know sometimes it's hard to judge from a picture.I have to determine if the problem is correctable is or not and if so, how? I also have to determine if there is anything unsafe and that may result in a premature or relatively near-term failure. Without further adieu - the post and some pictures and I thank you in advance for any replies.------------------I had a local welder weld some fittings into new 100 quart update international pots. The first contact with water was when I was passivating them early October. I used about a 3% concentration of nitric/phosphoric acid. - Loeffler KMS-10 which is formulated for this. I noticed almost immediately after finishing the passivation and flushing that every weld, particularly where ground, was developing what appeared to be rust. When I got home I tried to scrub the heck out of all the areas with Barkeeper's Friend. At first this seemed to work. But I'd come back the next day, and the rust would be right back. So after some reading, I found out the most likely scenario is that they introduced steel somewhere along the lines. Probably the grinding wheel - or maybe a brush. I also read the only way to fix this is chemically - that no amount of mechanical treatment will solve it. So I decided to run KMS-10 straight - which is basically around 40% phosphoric acid, and 15% nitric acid. All the reading suggested this combination should take care of removing the iron. So I decided to do a test soak - I soaked it for about 50 minutes. At first it was very promising - I saw no signs of rust. But after I got all the acid out and flushed it well, about 5 minutes and this is what I saw:If my eyes aren't deceiving me, I see pit corrosion. And not to mention it took almost no time for the rusting to start again. Anyone else agree with this? Any other comments on anything else I can try? At this point I'm close to throwing in the towel and calling the pots unusable. Just to reiterate - the pots have never been used!Here is the before:Thanks in advance.------------------
Reply:Originally Posted by DSWI reposted your text so it's readable. In the future resize your picts a bit smaller as this forum will cut off text if the picts are too large. ( last one was the killer)There is a process called "passivating" that is done to stainless to help eliminate these issues. Here's a quick link since I have to run to work now.http://www.mmsonline.com/articles/ho...ss-steel-partsGood luck.
Reply:Looks like they were welding too hot and burnt through all over the place. That's not supposed to happen. I wonder if they used a carbon buffing wheel. In reality, this is not supposed to happen - there are welders who can skillfully produce a sound quality weld with integrity - I would never go to that place again if they let that go to the client.46’ sae30047’ sa200 w/Wisconsin VF451’ shorthood56’ shorthood56’ shorthood68’ redface69 redface07’ ranger 305G13’ sae300Inconel/Hastelloy – SS – Duplex – Chrome/Carbon Tig – F3Downhand – STT/RMD – F3F4 – B Pressure
Reply:Originally Posted by ThortonLooks like they were welding too hot and burnt through all over the place. That's not supposed to happen. I wonder if they used a carbon buffing wheel. In reality, this is not supposed to happen - there are welders who can skillfully produce a sound quality weld with integrity - I would never go to that place again if they let that go to the client.
Reply:One problem was the shop you had do your work didn't know how to properly do sanitary welding and they basically told you what you wanted to hear to make a few dollars off of you.I'd take the pot back to the fabricator and show them the rust and demand my money back.Explain the health risk involved and ask them if there ok assuming the liability.You need to find yourself someone who understands sanitary work and they can do a simple job like this and make it look nice and simple.Where are you located?  Many on this forum such as myself can do this in there sleep.
Reply:Originally Posted by Showdog75One problem was the shop you had do your work didn't know how to properly do sanitary welding and they basically told you what you wanted to hear to make a few dollars off of you.I'd take the pot back to the fabricator and show them the rust and demand my money back.Explain the health risk involved and ask them if there ok assuming the liability.You need to find yourself someone who understands sanitary work and they can do a simple job like this and make it look nice and simple.Where are you located?  Many on this forum such as myself can do this in there sleep.
Reply:I'll add my two cents in by saying that I agree with the previous posters, and your own assessment.  The generalized rusting around the fitting is from iron contamination by a grinding wheel, wire wheel, or buffing/polishing pad that was used at some point on mild steel.  Passivating will not solve this problem.  A more aggressive process called Pickling will.  To make an analogy, passivating is like washing and waxing your car's paint.  Pickling is like using rubbing compound to remove scratches from your car's paint.  Pickling must be done with much stronger, and more dangerous acids, like hydrofluoric acid, and is not something I'd recommend you attempt yourself.  You might find a local industrial plater who has a pickling tank large enough to handle your pot.  But I'm guessing you're going to discover that it's more cost effective to start over with a new pot after getting a refund from you local welding shop.Problem number 2 is that your welder definitely used too much heat, either by setting their welder to high or moving too slowly while welding.  The blistering around the fitting is evidence this occurred.  This excess heat has sensitized the stainless steel around the weld, degrading its' corrosion resistance.This problem could be corrected by heat treating the entire pot in an industrial furnace that uses an inert gas atmosphere or a vacuum to shield the metal from the effects of oxygen and nitrogen in the air, at high temperature.  Again, I think you're going to find that the cost of heat treating this stainless pot will far exceed the cost of starting over.  Not to mention the high heat involved will likely warp your thin steel pot and leave you unhappy with the finished part.Your 18 gauge pot should be readily weldable by a skilled stainless steel fabricator, unless the couplers you're using are unusually thick.  In the event that they are, the fabricator could apply a doubler plate to the outside of the pot to ease the welding.  There are issues with the pot wall warping from the added heat and stress from the extra welding, so again, a skilled, experienced fabricator is a must.A final suggestion.  Keep your damaged pot and ask your fabricator to produce a sample of the work on it.  Assuming the whole pot wasn't contaminated by the previous welder, your new shop should be able to produce a solid example of their work.  I'd expect you to pay for this demonstration if they perform the work correctly and to your standards.  But at least you'll know you've found someone who can do the job and not ruin another pot.  Your welder can also experiment with machine settings on the ruined pot to dial in the process 100%.  Speaking for myself, I'd appreciate the chance to make a trial run on a project like this, since it's not something I do on a regular basis.  In this way, you might be able to take a shop this isn't an expert and aid them in getting up to speed.  Note:  I wouldn't pay to help an inexperienced shop or welder practice.  Only pay for the demo if you know you're dealing with experts, and asking them to spend their time giving you piece of mind.  But if you can't find an expert to do the job, this might be another way to get what you want.  Which is what really matters in the end.  Having your new pot wiht the fittings correctly welded into place.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by A_DAB_will_doI'll add my two cents in by saying that I agree with the previous posters, and your own assessment.  The generalized rusting around the fitting is from iron contamination by a grinding wheel, wire wheel, or buffing/polishing pad that was used at some point on mild steel.  Passivating will not solve this problem.  A more aggressive process called Pickling will.  To make an analogy, passivating is like washing and waxing your car's paint.  Pickling is like using rubbing compound to remove scratches from your car's paint.  Pickling must be done with much stronger, and more dangerous acids, like hydrofluoric acid, and is not something I'd recommend you attempt yourself.  You might find a local industrial plater who has a pickling tank large enough to handle your pot.  But I'm guessing you're going to discover that it's more cost effective to start over with a new pot after getting a refund from you local welding shop.Problem number 2 is that your welder definitely used too much heat, either by setting their welder to high or moving too slowly while welding.  The blistering around the fitting is evidence this occurred.  This excess heat has sensitized the stainless steel around the weld, degrading its' corrosion resistance.This problem could be corrected by heat treating the entire pot in an industrial furnace that uses an inert gas atmosphere or a vacuum to shield the metal from the effects of oxygen and nitrogen in the air, at high temperature.  Again, I think you're going to find that the cost of heat treating this stainless pot will far exceed the cost of starting over.  Not to mention the high heat involved will likely warp your thin steel pot and leave you unhappy with the finished part.Your 18 gauge pot should be readily weldable by a skilled stainless steel fabricator, unless the couplers you're using are unusually thick.  In the event that they are, the fabricator could apply a doubler plate to the outside of the pot to ease the welding.  There are issues with the pot wall warping from the added heat and stress from the extra welding, so again, a skilled, experienced fabricator is a must.A final suggestion.  Keep your damaged pot and ask your fabricator to produce a sample of the work on it.  Assuming the whole pot wasn't contaminated by the previous welder, your new shop should be able to produce a solid example of their work.  I'd expect you to pay for this demonstration if they perform the work correctly and to your standards.  But at least you'll know you've found someone who can do the job and not ruin another pot.  Your welder can also experiment with machine settings on the ruined pot to dial in the process 100%.  Speaking for myself, I'd appreciate the chance to make a trial run on a project like this, since it's not something I do on a regular basis.  In this way, you might be able to take a shop this isn't an expert and aid them in getting up to speed.  Note:  I wouldn't pay to help an inexperienced shop or welder practice.  Only pay for the demo if you know you're dealing with experts, and asking them to spend their time giving you piece of mind.  But if you can't find an expert to do the job, this might be another way to get what you want.  Which is what really matters in the end.  Having your new pot wiht the fittings correctly welded into place.
Reply:When the welder ground/sanded down the excessive penetration he used a rock/disk that has obviously been used on carbon steel. I once worked in a tank shop that did mostly stainless work but also the carbon work that came with it and if you were caught even throwing carbon grinding sparks on stainless you would get your last check and be walked out the door.
Reply:Let me ask this before I go to the welders: if the weld would have been good quality: is there any need for further treatment besides passivation?
Reply:A skilled welder could cut out the affected area and replace so don't consider your pot useless just yet. This isn't a big deal or a hard fix.You just need to find a qualified welder.
Reply:The problem is the one area you see, multiply that by 9. I had 9 fittings welded in, all with the same symptoms. And also they hit the bottom of the pot too which is tri-clad - I'm not so sure that can be repaired. Agreed or?
Reply:Originally Posted by jcaudillThe problem is the one area you see, multiply that by 9. I had 9 fittings welded in, all with the same symptoms. And also they hit the bottom of the pot too which is tri-clad - I'm not so sure that can be repaired. Agreed or?
Reply:$200...
Reply:You're going to need something more aggressive.  Nitrix/hydroflouric or muriatic acid.  Slightly elevated temperatures will help as well.  If it's carbon steel contamination, there's a good possibility that you'll have to remove some base metal to alleviate.
Reply:One more thing, copy this thread and all the replys and take it with you and show the person you deal with.There's more collective experience here than his shop will ever dream of having.
Reply:deleteLast edited by Kelvin; 11-07-2012 at 10:02 AM.
Reply:No, if the welding would have been done correctly, passivating would be the only thing necessary.Also, you might want to look into passivating with hot citric acid.  It's a little slower, and requires some heat, but the citric acid is much safer to work around than your phosphoric/nitric mix.good luck. Originally Posted by jcaudillLet me ask this before I go to the welders: if the weld would have been good quality: is there any need for further treatment besides passivation?
Reply:$200 for 9-10 couplers welded in?  so about $20 each?  That's below the range I'd consider reasonable, given the time, materials, skill, and care necessary to do the job.  Especially in a high(er) cost-of-living region like Norfolk or Hampton Roads. Originally Posted by jcaudill$200...
Reply:Originally Posted by A_DAB_will_do$200 for 9-10 couplers welded in?  so about $20 each?  That's below the range I'd consider reasonable, given the time, materials, skill, and care necessary to do the job.  Especially in a high(er) cost-of-living region like Norfolk or Hampton Roads.
Reply:I paid a hell of a lot less the first time I did this - you wouldn't even believe it. I still have one of the original pots and those welds have been just fine - no rust.I have no idea what welding should cost - $200 sounded in the range of reasonably professional to me.
Reply:If I were you, I would go in to the shop and ask "which apprentice weldedThis? It could very well be a journeyman who welded the material - I one time had "Edmund heads" from the 1940's from a ford flathead. Friend wanted meTo fix them but they were far, far too saturated & contaminated with grease, etc.. Stuff was very time consuming and needed to be machined - took them to "Charchun Welding" in Edmonton here; I Had someone drop themOff for me literally 3 times.. The 1st time it was only $200; had the aluminum heads dropped off again cause Charchun Welding in Edmonton Alberta here made a real mess of a job. Anyways, had them droppedOff again, the person dropping them off paid Charchun Welding an additional $100 to fix their poor excuse for work. Personally, I wouldnt have paid if I dropped them off, I probably would have broke everything in the shop because the heads weren't mine, but I was looking over them for the repairs. got the heads back, and the job Charchun Welding did was worse - destroyed them. terrible.46’ sae30047’ sa200 w/Wisconsin VF451’ shorthood56’ shorthood56’ shorthood68’ redface69 redface07’ ranger 305G13’ sae300Inconel/Hastelloy – SS – Duplex – Chrome/Carbon Tig – F3Downhand – STT/RMD – F3F4 – B Pressure
Reply:Besides the rust/corrosion issue there, you also have rather 'rough' welds that do not meet the needs for sanitary stainless welds (no rough spots or nooks/crannies/crevices that can trap things and bacteria).With having run some mild abrasive cleanser and also the passivating acids in the pot and still having rust/corrosion showing up after the pot 'looks' clean, I believe at this point you are dealing with pots that are pretty much ruined from overheating from the welding not from mild/plain steel contamination.With the passivating acids I think you have already removed any possible 'surface' plain-steel contamination and now are dealing with 'ruined' formerly stainless-steel pots that were maybe marginal as to their 'stainless' alloy.  What you have there (over the Net, from a few pictures, etc, etc, disclaimer) looks more like some wide-spread carbide precipitation corrosion from excessive and wide-spread over-heating of the pot during welding.  Weird corrosion pattern though, as it is wide-spread and non-uniform.Over-heating of 304 during welding (worst-case temperature is 1200F, range for carbide precipitation is 800-1650F) led to the chromium (what makes the stainless steel actually "stainless") joining with the carbon in the steel and forming chromium carbide,  Hard stuff, but now the chromium is no longer 'free' to keep the steel from rusting.  Annealling the steel at 1800-2150F and then rapidly cooling may restore the original (and desired) stainless corrosion resistance.  But I think unless you somehow find a heat-treatment shop willing to put your pots in with some other running 304 annealment job, the cost to anneal them would pretty much make those pots as 'ruined'. Even if you did anneal them and removed all the carbide-precipitation, you now have at least minor surface pitting (from all the corrosion) that would have to be polished out so as not to set up contamination trap points for food-service.  As well as those non-acceptable rough welds that would have to also be redone (possible GTAW smoothing and/or careful grinding/polishing to meet sanitary-service workmanship requirements).Not smooth welds, not done smoothly to begin with and not ground smooth afterwards, as well as the carbide-precipitation corrosion and those pots are NG for food service.  IMNSHO.  The best laid schemes ... Gang oft agley ...
Reply:This is some good background info:http://www.bssa.org.uk/topics.php?article=55"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welderWhat you should do is take these welds to the various weld test centers (where they have welding Examiners) and ask them to give you a written document as to why the weld fails, what the weld faults are and anything else they want to write about it - and get enough welding Examiners looking at these welds, then when you have the documentation of what is wrong with the welds, go back to tge shop that welded them and say "here you go - This is why your have pisspoor quality welds and here's what's wrong with the welds. Because you see, some companies are going to try and bully you and say "oh there's nothing wrong with an ugly weld, there's nothing wrong" and if you ever go to court, and I've been to court before, I gotta go here regarding a lawyers' poor work ethic; more like lawsociety, not so much court, but you want documentation. Other people who are not familiar with welding - if the Welsing company says "we've been in welding for over 30 years, an ugly weld, or a little bit of contamination does not effect the metal, we're experts at this - people will believe them and you won't have a case because it's all about confidence. A Welding examiner if he's years upon years of experience and many tig welders who are obsessive about quality work will tell you that that **** protruding through the backside of the weld, that's - did some failure apprentice weld that whose just learning? Or? I would get lots of documentation on the piece. If you want, even figure out what the companies clients are and pay their clients a little visit, and show them the "quality" of work that the company does. Sorry for tge rant, but from experience, if you want something done properly, you do it yourself otherwise counting on other people - lawyers, mechanics, teachers, etc - some people don't respect their line of work/appreciate the history, and people who are only in it for the money put out work like this. Many places also overcharge big big time! It's like some companies and some people have no shame to realize they are bot as good as what they figure. Anyways - show tge welds around and get documentation on them with all weld faults so that you can shove the documentation in tge face of the shop and have them fix or replace *now* NOW free-of-charge.46’ sae30047’ sa200 w/Wisconsin VF451’ shorthood56’ shorthood56’ shorthood68’ redface69 redface07’ ranger 305G13’ sae300Inconel/Hastelloy – SS – Duplex – Chrome/Carbon Tig – F3Downhand – STT/RMD – F3F4 – B Pressure
Reply:Originally Posted by A_DAB_will_doNo, if the welding would have been done correctly, passivating would be the only thing necessary.Also, you might want to look into passivating with hot citric acid.  It's a little slower, and requires some heat, but the citric acid is much safer to work around than your phosphoric/nitric mix.good luck.
Reply:Carpenter Technology's website has an excellent discussion of passivation techniques, both with nitric acid and with citric acid.  http://www.cartech.com/techarticles.aspx?id=1566when I've passivated parts in the past, I purchased citric acid in a powder form from a chemical supply house, and diluted it in de-ionized water.  Carpenter's website gives you the relevant concentrations, times, and temperatures.  They also have a good discussion of the pros and cons of the two passivation methods, and some practical dos and don'ts.Their procedures and advice are aimed at a more industrial SS fabrication environment than your situation represents.  So be prepared to read and interpret their advice for your particular circumstances.As always, use common sense and safe practices when mixing and using acid solutions.  Citric acid is very safe, but the nitric acid procedures they discuss require a good understanding of safe handling and disposal procedures.   Originally Posted by jcaudillCan you tell me what type of citric acid to use? I've been trying to search a bit online about passivating with citric acid and I found enough about the actual process, but not much about what type to buy.Thanks very much.JP
Reply:Originally Posted by A_DAB_will_doCarpenter Technology's website has an excellent discussion of passivation techniques, both with nitric acid and with citric acid.  http://www.cartech.com/techarticles.aspx?id=1566when I've passivated parts in the past, I purchased citric acid in a powder form from a chemical supply house, and diluted it in de-ionized water.  Carpenter's website gives you the relevant concentrations, times, and temperatures.  They also have a good discussion of the pros and cons of the two passivation methods, and some practical dos and don'ts.Their procedures and advice are aimed at a more industrial SS fabrication environment than your situation represents.  So be prepared to read and interpret their advice for your particular circumstances.As always, use common sense and safe practices when mixing and using acid solutions.  Citric acid is very safe, but the nitric acid procedures they discuss require a good understanding of safe handling and disposal procedures.
Reply:Thank you, Mr. B--for the Carpenter articleBlackbird
Reply:Here's the latest:I took it back to them today. They acknowledged the problem and they understood and agreed it could not be used for food service. I told them try whatever they want to try because at this point it's that or the pots have to be replaced. I also asked them to cleanup the sugaring. They said this is the 2nd time they've encountered this in 25 years of service. They said they've worked on a lot of food service equipment. But yes I do know working on equipment and knowing how to do sanitary welds are two different things.I got a message later in the day saying he had used some 120-grit sandpaper and hit the areas of concern. He then watered them down and as of the end of the day no rust returned.I am both optimistic, and worried. The optimistic side says maybe it just hadn't had the chance to go deeper. The worried side says what if it comes back later.I think he's going to run the flap wheel on all the areas to clean them up.Any thoughts on all of this?Someone told me even if the rust is gone it's too late because the alloy in the stainless has been hosed.
Reply:Your welcome.As far as dilutions are concerned: 10% By weight...literally is 1 part in 10;  It's easier method for expressing the amounts  for dissolving solids into liquids.  For example,  1 lb of citric acid powder plus 9 pounds of water gives you a 10% solution by weight.  The units don't matter, could be Kg or ounces, or tonnes. 10% by volume...usually only when mixing liquids together, but same idea.  1 gallon of pure acid to 9 gallons of water makes a 10% solution.  Except, if your acid is already diluted(as most are).  Then you'll have to do some math to figure out the proper amounts. Starting with 20% concentrated Nitric acid, need 10% by volume.  Take 1 gallon of 20% solution and add it to 1 gallon of water; presto 10% solution by volume.   Originally Posted by jcaudillThat works - thanks! When I've used nitric acid, it's in a pretty weak concentration and I do it in the brewery where there's proper drainage and everything can be well hosed down. For my home, I definitely want to go with citric since I can safely dump this with no environmental impact. I'll read something earlier today about citric passivation and the general recommendation was 15% by weight at room temp for an hour. I'll read through your link and see how that matches up. Of course I've been wondering how the whole by weight thing works - little puzzling.
Reply:You're welcome. Originally Posted by dave powelsonThank you, Mr. B--for the Carpenter article
Reply:Mechanical grinding can remove iron contamination.  But in your position, I'd wonder how much he thinned out the 18 gauge material in the process?If exposure to water and air produces no flash rusting overnight, you're over the first hurdle.  If the surface contamination is fixed, you might get some use out of the pot before the sensitized areas begin to rust.  It might even last until something else goes wrong first, like a thin spot cracking under the weight of the contents.  Or your pot may be toast right from the first batch of product you brew in it.  It depends on how agressive the solution you're brewing is.   If you can gamble on throwing out a batch of product when you discover rust in the pot at some time in the future, then it might be worth trying out.  But if the consequences are too severe, then perhaps its better not to gamble at all.  Only you can be the judge of what's right under the circumstances. Originally Posted by jcaudillHere's the latest:I took it back to them today. They acknowledged the problem and they understood and agreed it could not be used for food service. I told them try whatever they want to try because at this point it's that or the pots have to be replaced. I also asked them to cleanup the sugaring. They said this is the 2nd time they've encountered this in 25 years of service. They said they've worked on a lot of food service equipment. But yes I do know working on equipment and knowing how to do sanitary welds are two different things.I got a message later in the day saying he had used some 120-grit sandpaper and hit the areas of concern. He then watered them down and as of the end of the day no rust returned.I am both optimistic, and worried. The optimistic side says maybe it just hadn't had the chance to go deeper. The worried side says what if it comes back later.I think he's going to run the flap wheel on all the areas to clean them up.Any thoughts on all of this?Someone told me even if the rust is gone it's too late because the alloy in the stainless has been hosed.
Reply:When you talk about the possibility of failure, it sounds like you're thinking it would happen fairly quickly. Not months, years?
Reply:Originally Posted by jcaudill I took it back to them today. They acknowledged the problem and they understood and agreed it could not be used for food service.120-grit sandpaper and hit the areas of concern
Reply:Originally Posted by jcaudillWhen you talk about the possibility of failure, it sounds like you're thinking it would happen fairly quickly. Not months, years?
Reply:Ok, all I needed to know.One thing I'll toss out - though won't really matter: they said their welding tool supplier is the one who recommend the sandpaper approach - along with synthetic steel wool.
Reply:Originally Posted by jcaudillOk, all I needed to know.One thing I'll toss out - though won't really matter: they said their welding tool supplier is the one who recommend the sandpaper approach - along with synthetic steel wool.
Reply:I am not a sanitary welder but have worked on several sanitary jobs involving both food processing equipment and installing beverage bottling facility piping and there is 0 chance of those welds passing to sanitary standards.  The shop that did them ought to a) be ashamed of themselves and b) not taken the job on in the first place.  the first sign of a hack is someone who doesnt have enough care or respect for their craft to know when to step aside and let those more versed handle a project.  It's too bad, when done properly sanitary stainless is a thing of beauty.
Reply:Thorton,Thanks for posting the link to AMI Orbital Welding's website.  Good article with lots of good information.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:there's no way for me to predict when it might fail.  Too many unknowns.  Could be the first time you use it, or anytime(including never) thereafter.  That said, the odds of getting long life out of the pot in in it's current state are very, very low. Originally Posted by jcaudillWhen you talk about the possibility of failure, it sounds like you're thinking it would happen fairly quickly. Not months, years?
Reply:Ok... fair enough!Thanks. Still losing a lot of sleep over this mess!
Reply:Ok I have decided that I'm going to abandon these pots because the truth is after reading everyone's replies here and on the other forum I'm always going to be worried about the possibility of imminent failure or continued rusting issues. I told the welding company to stop working on the pots and I will come pick them up tomorrow. I plan to have a discussion with them then to see if they will accept any responsibility.It seems a challenge for me that there is some speculation in that many of the issues presented here may or may not crop up in the near future. So on the surface, nothing is "wrong". This makes it difficult on me.So I want to be armed with as much "fact" as possible when I go in. Would someone here be willing to sum up what is pretty darn close to factually wrong with this?Know that at this point, in their minds, nothing is wrong. They claim to have corrected the contamination by what in their summary was with 120-grit sandpaper and then I'll make an assumption maybe they used a flap wheel after that to cleanup things. I have not seen the pots since dropping them off Thursday.Thanks in advance.
Reply:What is factually wrong is that they took no effort to sheild the backside of the weld from oxygen from the air that caused sugaring that traps contaminants that bacteria thrive on.Then they tried to dress it up and compramised the material side adjacent by embedding corrosion prone elements deep into the surface. Those elements will result in intergranular corrosion from bacterial as well as chemical reaction.The only proper way to save the pots is to cut out the bad material, replace with fresh metal, purge or flux, and reweld.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:From what I see, that is unacceptable work, done by a shop that had no knowledge of what you asked. As far as I am concerned  that vessel is now a trash bin. I am willing to bet the fit was NFG and no form of back purge was used. It looks like it was boogered in there by a monkey with a 110 MIG .Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:Originally Posted by jcaudillKnow that at this point, in their minds, nothing is wrong. They claim to have corrected the contamination by what in their summary was with 120-grit sandpaper and then I'll make an assumption maybe they used a flap wheel after that to cleanup things. I have not seen the pots since dropping them off Thursday.Thanks in advance.
Reply:*ALSO* think to yourself, "If they say that they dont see anything wrong with their welds", then WHY? are they yet again trying to fix them? If the weld was done right the first time, they should not have to be fixing them. I bet you that the welds are going to be in even worse shape when you get them back - they will probably be missing a great deal of material thickness when they go to "smoothen out" the backside of the weld where it was all pathetic and rough - where the stainless was far, far too hot for the base metal and the weld sunk down. I bet you that they probably kept welding and welding away even when the stainless was getting hotter and hotter - stainless will start to sink in on itself - it is a very sad state to see.46’ sae30047’ sa200 w/Wisconsin VF451’ shorthood56’ shorthood56’ shorthood68’ redface69 redface07’ ranger 305G13’ sae300Inconel/Hastelloy – SS – Duplex – Chrome/Carbon Tig – F3Downhand – STT/RMD – F3F4 – B Pressure
Reply:Thorton, if you still need the heads done Zap's buddy is a head guy. It might be worth sending the set south for a propped job.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:Originally Posted by TozziWeldingThorton, if you still need the heads done Zap's buddy is a head guy. It might be worth sending the set south for a propped job.