Keggle Weld/Build Questions

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JFlowers1300

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Hello, I'm a long time reader, but this is my first post on the site. I'm in the process of building 3 keggles, a HLT, MLT and a BK for a future HERMS system. I've been trying to collect as much info as I can prior to welding as to how I should have the 1/2" couplers welded on? I have gathered from the threads that I've read that backing with argon is preferable, however, the welder I talked to suggested tig welding the couplers from both sides of the keg walls which he said would form a food grade seal? (I already have the tops already cut off and the holes drilled in the kegs.)

I have no experience dealing with welding or welders but some of the work they showed me looked very clean and solid and they do have experience working with stainless.

The only issue I feel that I have is that they seemed to be very busy and wouldn't give me a price to back the kegs with argon after they quoted me $15 per coupler (inside and outside). However the welder did say that argon gas was produced by the torch they would be using to purge the oxygen from the surface they would be welding, is this accurate? Is there any downside to having the couplers welded on this way or should I take a chance finding someone else who will back the keg with argon?

Also I am planning on having the 1/2 couplers welded on so that they are close to flush on the inside of the keg so that the majority of the couplers face the outside of the keg shell, is there any reason that I should place them more 50/50 inside and out?

Thanks in advance for any advice, it's most appreciated!:mug:
 
Not sure what they are referring to as "backing with argon". What the welder guy was talking about was the argon gas he will be using in his welder which is pushed over the weld during the process. TIG = Tungsten (the arc tip metal) Inert Gas (argon in this case). The biggest thing would be to have a smooth weld with no pitting that would tend to hold contaminates.
After your previous research you may very well have know all that, but guess it can't hurt to see repeats......:mug:
 
Thanks for the info, I guess in my head from reading the other posts I was envisioning the gas needing to be opposite the side they would be welding? Like I said I have absolutely zero experience with anything that has to do with welding :drunk:.
 
That wouldn't be a bad thing, but IMO it wouldn't be necessary (says the faceless stranger that has nothing to loose..:ban:). If they were brazing I'd be more concerned, but the TIG should be injecting enough gas to the molten metal to keep the oxygen and impurities at bay. By welding both sides, no surface metal will have been molten while exposed to the air.
Ask them to be careful not to inject ferrous metal into the weld with grinders or steel wire wheels/brushes. If you've seen his welds on stainless and they actually looked good, then he's probably experience enough not to do this anyway but it can hurt to ask.

[EDIT] Should explain that a LOT of people say the weld SS, but the ones that can make it look good are far and few between.
 
Without backpurging the weld area, it's going to sugar so bad that laying another bead on that surface is going to require a LOT of cleanup after the first weld. Have them put it in writing that both sides of the weld will be clean without sugaring. Otherwise:
DSC02454.jpg
 
Without backpurging the weld area, it's going to sugar so bad that laying another bead on that surface is going to require a LOT of cleanup after the first weld. Have them put it in writing that both sides of the weld will be clean without sugaring. Otherwise:
DSC02454.jpg

Wow! Was that a MIG or TIG weld?
 
Awesome, I REALLY appreciate the clarity and advise. Between the time it's taken me to get the kegs and prepare them to be welded and the fact that I've not been able to work on this project as much as I would have liked over the past 6 months, I am doing everything I can to hopefully get things as right as possible the first go around without having to revert back to square one.

Doing all the research and finding someone I like to have these things welded has just been one of those sticking points in this project where it feels like the whole thing is going nowhere until I get it done.
 
Is that what will happen if it's not backed purged with argon gas regardless of the welder's ability?

Yes. When the molten stainless comes in contact with Oxygen it will 'sugar' (See Bobby's picture). It doesn't matter how talented the welder is or if they use MIG or TIG.

TIG is the way to go and that flows Argon from the tip to shield the front side weld. You will need to purge from the backside. I'll copy/paste this which I wrote in a different post on the same subject:

"As for what welding should cost... Most back yard garage welders will tell you they can weld stainless. Ask if they can sanitary weld / back purge with Argon (same thing). If they look at you with a deer in headlights look keep on looking around.

Once you find someone that can weld SS I would estimate between $20-$40 per weld. It only takes 5-10mins per weld but they will need to set up a rig to backpurge. More than likely they won't have one lying around That set up time could take an hour or more. That's where all the cost comes from."

If you have any questions feel free to PM or call!

-Ben
 
Is that what will happen if it's not backed purged with argon gas regardless of the welder's ability?

Exactly. Every welder worth his salt should back flush these welds. Obviously, a sanitary weld is not required in this scenario but back flushing doesnt take that much extra effort. It can be set up with cardboard and duct tape.
 
Alright, thanks to everyone for the advice. It's really starting to sound like my initial worries about this place might be accurate. It seems like they just don't want to take the time to do what I need them to, the welds will just have to wait a little while longer to be done right, unfortunately, but at least my kegs weren't ruined figuring that out the hard way!
 
Okay, injecting ferrous materials is one thing that should be avoided in the grinding and finishing process.

BUT - you guys are a little nuts with the back flushing of the welds. I have done a lot of welding in my time, took a night school class to learn it and improve my skills, and worked in industrial maintenance for a large national poultry processing plant that produced all of the chicken for Wendy's chicken sandwiches globally. I was the welder for my shift and everything there was stainless. I can tell you that in an FDA inspected plant, there was never back gassing of the welds. If properly shielded with argon and tig welded, then there will be no sugaring, porosity, or issues. By welding from both sides as the welder suggested above, this will further flush and smooth the weld. This is often called tig washing by experienced welders and is a process used in food service applications to smooth and flush the weld bead without grinding.

Think about it this way, when you boil something like wort, the by-products rise through the liquid and escape out of the top surface of the liquid. The same thing happens in a weld. When you strike an arc and burn in to your base metal, you push the impurities to the surface of the weld. The shielding gas displaces the impurities and keeps them from re-entering the weld surface until it has cooled. The sugaring that you get on the back side of the weld is from the arc burning through on the back side of the thin metal and that is partly inexperience of the person welding but nothing that a tig wash on the back side won't fix.

Do you really think that welders back gas large welds in bulk holding tanks or vessels in food processing plants? No way as it is impractical and unnecessary. That may be the reason that some welders look at you like you have two heads.
 
Okay, injecting ferrous materials is one thing that should be avoided in the grinding and finishing process.

BUT - you guys are a little nuts with the back flushing of the welds. I have done a lot of welding in my time, took a night school class to learn it and improve my skills, and worked in industrial maintenance for a large national poultry processing plant that produced all of the chicken for Wendy's chicken sandwiches globally. I was the welder for my shift and everything there was stainless. I can tell you that in an FDA inspected plant, there was never back gassing of the welds. If properly shielded with argon and tig welded, then there will be no sugaring, porosity, or issues. By welding from both sides as the welder suggested above, this will further flush and smooth the weld. This is often called tig washing by experienced welders and is a process used in food service applications to smooth and flush the weld bead without grinding.

Think about it this way, when you boil something like wort, the by-products rise through the liquid and escape out of the top surface of the liquid. The same thing happens in a weld. When you strike an arc and burn in to your base metal, you push the impurities to the surface of the weld. The shielding gas displaces the impurities and keeps them from re-entering the weld surface until it has cooled. The sugaring that you get on the back side of the weld is from the arc burning through on the back side of the thin metal and that is partly inexperience of the person welding but nothing that a tig wash on the back side won't fix.

Do you really think that welders back gas large welds in bulk holding tanks or vessels in food processing plants? No way as it is impractical and unnecessary. That may be the reason that some welders look at you like you have two heads.

Every tank I ever had any retrofit welding on from 50bbl to 300bbl had the weld back flushed. I agree it is not always necessary when using low heat and a tig torch. I do think that if the welder in question did a good job on the outer weld, that doing follow up pass on the back would yield a good product. But most welding shops just break out their MIG and leave results like the first couple posts.
 
I dare the OP to let that guy weld on his kegs and post pictures later. I love Wendy's spicy chicken sandwich, but now I'm worried about eating them ;-) Just kidding. This is the first time I've ever heard of a sanitary welder not back gassing. If you get penetration on the keg wall, you'll get sugaring. Back gassing with argon is the simple way to avoid this and if you use a volume reducing attachment, you don't spend up all your gas in the process. In vessels this size, there really is no room to get in there and play around with welding from the inside. Most of the sanitary standards that the FDA would lean on are specific to the dairy and pharma industries and even a quick glance from someone outside of that industry can find back purging language. Hey, what do I know. I have never TIG welded in my life so I could be blowing smoke, but I do know how to read. That's probably just enough info be an ass though.
 
I will accept the challenge and be willing to post the pictures myself. If the OP wants to pay to ship the keggles both ways to Georgia, send the fittings, and throw in $20 for the consumables that I use, bring it on. I am not trying to be arrogant or assinine. I would say that back gassing is an insurance policy against a crappy weld from an unskilled or unprepared welder.

As far as mig welding stainless goes I have never attempted it and don't know what the results would be if I tried. In my opinion, this is one of those ares where just because you CAN doesn't mean that you should. I can say that the weld pictured earlier in the post was something that was not tig.
 
Bobby_M said:
I dare the OP to let that guy weld on his kegs and post pictures later. I love Wendy's spicy chicken sandwich, but now I'm worried about eating them ;-) Just kidding. This is the first time I've ever heard of a sanitary welder not back gassing. Hey, what do I know. I have never TIG welded in my life so I could be blowing smoke, but I do know how to read. That's probably just enough info be an ass though.

For the record, I still eat chicken sandwiches from Wendy's. I always thought it a bit macabre but the served fried chicken in the cafeteria almost every day...and it was good chicken.

And Bobby, you aren't blowing smoke....you are back gassing :).
 
Argoodin is correct in a way on this. The picture Bobby posted has something that protrudes through the sidewall. In this case you would need to purge the otherside with argon. If you make the hole smaller on the keg and weld a half coupling to the sidewall you don't have to purge the otherside and worry about sugaring. All of the argon will be shielding the puddle on the front when the half coupling will be welded to the keg. If the welder burns through that keg then yes it will reach oxygen and cause sugaring. A lot of pipe fitters love the socket weld style fittings because it's a small fillet weld that doesn't require purging.

On the flip side of this is trying to be as sanitary (clean and smooth) as possible for us homebrewers to avoid small places for infections to form. You do want to purge and get the puddle hot enough to create a nice bead on the inside as well. If you don't have your heat high enough and just join the top layer of metal together, you'll still have a lip/crack where the two joints meet on the inside which can leave an area for bacteria and junk to form. You want that puddle of molten metal to go all the way through to have a nice bead both inside and out for 16ga (.065) sanitary systems.

Like others have said I'm no certified welder that been welding for decades but I've been around stainless welders that have.
 
By welding from both sides as the welder suggested above, this will further flush and smooth the weld. This is often called tig washing by experienced welders and is a process used in food service applications to smooth and flush the weld bead without grinding.

The problem in a lot of our setups is that you cannot weld from both sides when the coupling sits as low as it does in the kettle.
 
Agreed, as I have welded these fittings before and it is extremely difficult if not impossible to get to the underside of the coupling on the interior of the keg. Personally, I insert a pipe plug into the fitting to keep the threads in good shape and only insert the fitting far enough into the keg to get a good joint. I haven't found a reason to shove the fitting any farther in than that and it leaves some room to get the torch in on the underside in the interior of the keg.

I agree with using sockets wherever possible.

I guess that I should take a step back and clarify my position on this...back gassing has its place and its use. It may be preferable in some situations in order to achieve a sanitary weld. Is it absolutely necessary, no.

AG
 
argoodin,

I'm sorry but whoever you worked for had the FDA in their pocket.

If you were welding thin walled stainless there's no way you only welded with shielding on the weld side and upheld the integrity of stainless steels corrosion resistance on the back side of the weld.
Even the discoloration from heat tint on stainless means that stainless steels corrosion resistance is compromised in that area. Therefore it should be removed mechanically or chemically.

The only way "back gassing" is not necessary is if the material was thick enough to absorb the heat, and you were not doing full penetration welds.

By the way, have you ever pipe or tube welded to code standards requiring inspection?
Purging the inside of the pipe or tube with Argon while welding is absolutely required. Period!

Protecting the backside of thin walled stainless with Argon is standard procedure when welding, and if not, it's being done half-assed.
 
As far as sanitation goes, the keggles will be at a high enough temp for enough time to kill any bacteria or such right?

I know this debate is about purity and optimum scenarios for sanitary welding. Clean tig welding with an atmosphere purged of oxygen is the only way to go. I cant think of any reason why you would not take the time to purge/sheild both sides of a thin walled vessel.

However... Its not a Fermentation vessel.

Im just wondering if sugaring and porosity really pose a considerable threat in the big scheme of things. can you still have a contamination threat after cleaning and boiling the keggle?
 
As far as I can see I still have both the left and right butt cheeks.

In response to the testing, no I have not. Structural, yes but stainless sanitary no. I am sure that there are certainly more qualified people out there in the field of sanitary stainless welding than I am. What I can speak to and have been speaking to is the fact, not the theory, that I personally have welded plenty of stainless and have never had issues with the corrosion, pitting, etc. that is associated with bad welds. Many of my welds were in locations subjected to a constant regiment of chlorine and other caustic sanitizers. Am I an expert, no. Do I have more experience than people who read about what should and should not be done, yes.

Again, back gassing has its place but is it absolutely necessary, no. I agree with the last poster in terms of the use of the welds in a high temp environment. Are we making plutonium powered homebrew rigs that must meet the latest FDA, USDA, EPA, and OSHA standards, no. There is a point where "knowledge" outweighs reason, experience, and skill. The reason for not back gassing, particularly in large vessels, cost. Pipe and tube is a little different environment in that regard and yes, I am aware that there are instances where this procedure is required to be and should be used. I am pretty sure that I acknowledged that in a prior post.

I just keep reading all of these multiple posts with people acting like you are going to kill the baby Jesus if you don't back gas your welds and you should treat any welder/fabricator that doesn't like they just fell off the turnip truck. It annoys and frankly frightens me a little bit.
 
As far as sanitation goes, the keggles will be at a high enough temp for enough time to kill any bacteria or such right?

I know this debate is about purity and optimum scenarios for sanitary welding. Clean tig welding with an atmosphere purged of oxygen is the only way to go. I cant think of any reason why you would not take the time to purge/sheild both sides of a thin walled vessel.

However... Its not a Fermentation vessel.

Im just wondering if sugaring and porosity really pose a considerable threat in the big scheme of things. can you still have a contamination threat after cleaning and boiling the keggle?

In the case of hot side brewing it's not important to have everything sanitary, just clean.
Sugaring results from poor welding procedure, and can trap debris making the area hard to keep clean. Stainless is no longer stainless in that area, and it's ugly.
Porosity can happen to any welder, but a good welder keeps flaws in his welds to a bare minimum and fixes his mistakes.
It's not so much a sanitation issue, as it is pride in workmanship.
Me personally, don't do half-assed.

When I weld for someone I try to surpass their expectations and usually do.
I'd rather have someone ecstatic over my work, than just thankful.
 
Is there a compelling reason not to go weld less? I also have 3 keg getting ready for conversion. Tops are off.
 
^^^This is exactly what I'm wondering at this point. With all the time I've already put into cutting, drilling and polishing up my kegs and the fact that I am going to be putting much more time and money into completing my brewery as a whole, an extra $15-$20 a weld doesn't seem like a high price to pay to ensure that I get good welds. I understand from the previous posts that there may be people out there who can weld without back flushing with argon, but it seems to me that I am taking a much larger risk accepting this and possibly getting a hack job than finding someone who will take the time to do a more detailed and albeit safer job with back flushing (safer in the sense that sugaring is less likely to happen when back flushing).
 
Dude, you're over thinking things. Just take it to a professional and pay them to weld it for you. You're already saving money by using keggles.
 
He's not overthinking it at all. Everyone that comes here to post pictures in a thread titled something like "do these welds look OK?" took a "professional's" word for it that they knew how to properly weld stainless. There's nothing like toiling for months trying to find some kegs, cleaning them up and then having some hack screw them up completely and then act like you should do jumping jacks over the work.

img0441.jpg
 
^^^I can't believe I hadn't thought of that already, lol! There is a micro brewery 5 mins from my house. Gives me a reason to go up there :rockin:. Thanks!
 
If your considering going weldless have you looked at silver soldering? (is this an electric or gas build?) There's a huge thread sticky in the DIY forum with more info.
 
It will be a gas build at least to begin with, I've looked into silver soldering, but I'd really like to have them welded.
 
Got all my welds completed and couldn't be happier, I'll post the pics as soon as I get them off my phone. Thanks to everyone who posted a response to my questions, the advice I received was and is greatly appreciated. I ended up taking a little more time and found a custom fabrication company to back flush and weld them for me.
 
14, planning on building a single teir HERMS system. MLT and BK have 4 total welds each will have a sight glass, thermometer, ball valve and return and HLT has 6, 4 for everything previously mentioned but with two additional for the coil.
 
I just had this welded the other day. How does it look to you guys??
My main worry is the little gap on the inside of the ferrule. This is my book kettle so maybe I'm worrying over nothing? Should I leave it out have someone fill the little seam?

The first 2 pics are the inside of the 2" tri clamp ferrule

170993d1389221312-weld-ok-image.jpg


170991d1389221074-weld-ok-image.jpg
 
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