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-   -   Keggle Weld/Build Questions (http://www.homebrewtalk.com/f11/keggle-weld-build-questions-372273/)

JFlowers1300 12-06-2012 03:01 AM

Keggle Weld/Build Questions
 
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:

501irishred 12-06-2012 03:12 AM

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:

JFlowers1300 12-06-2012 03:30 AM

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:.

501irishred 12-06-2012 04:01 AM

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.

Bobby_M 12-06-2012 04:08 AM

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:
http://i89.photobucket.com/albums/k2...2/DSC02454.jpg

501irishred 12-06-2012 04:27 AM

Quote:

Originally Posted by Bobby_M (Post 4654360)
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:
http://i89.photobucket.com/albums/k2...2/DSC02454.jpg

Wow! Was that a MIG or TIG weld?

JFlowers1300 12-06-2012 04:28 AM

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.

JFlowers1300 12-06-2012 04:31 AM

^^The above is the exact opposite of what I want to have happen.^^

JFlowers1300 12-06-2012 04:33 AM

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

SpikeBrewing 12-06-2012 04:41 AM

Quote:

Originally Posted by JFlowers1300 (Post 4654420)
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


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