[glassTransition]

Hi, I plan to weld a 1/2" NPT fully threaded female pipe fitting through the wall of a beer keg. Both are 304. The fitting is about .1" wall and the keg is about 16 ga. I would like to keep the joint autogenous.

My first question is about joint prep. Should I just keep the sides of the hole in the keg as-is (square) after drilling or should I bevel them?

My second is whether I should wash the external joint back and forth, pulse along the seam, or just drag the puddle straight around? I've read some of Rick_H's comments about 2.5 pps, 50%, and 50 amps and this makes sense to me and I've done that sort of thing on other jobs.

Finally, I will position the fitting so it is close to flush on the inside of the keg. Is it necessary to run a washing bead on the inside or can I rely on full pen to make the inner surface smooth? Of course it will be back purged. It will be difficult to get to the inside of the fitting as it will be near the bottom.

Thank you!

[Poland308]

If you have a good back purge there shouldn't be any need to bevel the keg wall. It's pretty thin. Run a few test pieces and you will get an idea of how hot to run to get full penetration on the keg for a fairly smooth back.

[exnailpounder]

I weld kegs all the time. Kegs are 18ga. Don't bevel anything or you'll be sorry. When welding thick to thin, concentrate your heat on the thick and wash onto the thin. I cut nipples in half and fusion weld them to the side of the keg and drill the hole afterwards. You can use filler if you want but it's not necessary. You don't need any pulse. You need to know how to use a foot pedal. Your fitting doesn't have to be flush on the inside of the keg. Purge the keg, weld a little and stop, put some wet rags on the keg to draw out some heat. Don't worry about pretty, weld a little and stop otherwise you will end up with cracks. Don't over-think it. Make sure you purge it good pay attention to controlling the heat. It's not hard so don't make it that way.Post up some pics.

[DLewis0289]

Put a plug in it and don't take it out until it's cool.

[Rick_H]

I weld kegs all the time. Kegs are 18ga. Don't bevel anything or you'll be sorry. When welding thick to thin, concentrate your heat on the thick and wash onto the thin. I cut nipples in half and fusion weld them to the side of the keg and drill the hole afterwards. You can use filler if you want but it's not necessary. You don't need any pulse. You need to know how to use a foot pedal. Your fitting doesn't have to be flush on the inside of the keg. Purge the keg, weld a little and stop, put some wet rags on the keg to draw out some heat. Don't worry about pretty, weld a little and stop otherwise you will end up with cracks. Don't over-think it. Make sure you purge it good pay attention to controlling the heat. It's not hard so don't make it that way.Post up some pics.

Agree 100%... good advice. I play with pulse when I'm doing the piping, but when I weld fittings, most of the time I use 2T with the ramp down, or foot pedal. I've drilled the hole making it fit the ID of my fitting (typically my fitttings have valves and some weight hanging off of them), weld the outside with a ID purge, fillet weld with filler, then fusion the weld the inside seam, polish it out and go....

The key is watching the heat so you don't suck the side wall in so bad...

[exnailpounder]

I weld kegs all the time. Kegs are 18ga. Don't bevel anything or you'll be sorry. When welding thick to thin, concentrate your heat on the thick and wash onto the thin. I cut nipples in half and fusion weld them to the side of the keg and drill the hole afterwards. You can use filler if you want but it's not necessary. You don't need any pulse. You need to know how to use a foot pedal. Your fitting doesn't have to be flush on the inside of the keg. Purge the keg, weld a little and stop, put some wet rags on the keg to draw out some heat. Don't worry about pretty, weld a little and stop otherwise you will end up with cracks. Don't over-think it. Make sure you purge it good pay attention to controlling the heat. It's not hard so don't make it that way.Post up some pics.

Agree 100%... good advice. I play with pulse when I'm doing the piping, but when I weld fittings, most of the time I use 2T with the ramp down, or foot pedal. I've drilled the hole making it fit the ID of my fitting (typically my fitttings have valves and some weight hanging off of them), weld the outside with a ID purge, fillet weld with filler, then fusion the weld the inside seam, polish it out and go....

The key is watching the heat so you don't suck the side wall in so bad...

I usually don't have access to the inside of the keg like you would for an HLT. I weld for distillers so the top of the keg stays on. Heat control is paramount but I have had keg walls fold a bit and I just put a nipple in my half coupler and bend it back to where it should be, you may get a stress crack from that but I test my welds. Thin stainless is a trick because when you weld thick to thin it cools at a different rate and can crack if you get lazy and try to finish without heatsinking. You won't know it if you don't test for leaks and rely on visual. If I am welding on a nipple, I use a uni-bit until I get the hole big enough that I can thread the nipple into the keg up to the shoulder and then I usually just fusion weld it or sometimes add filler to control the heat a bit. I try to stay as sanitary as possible but without access to the inside of the keg, I have to rely on the purge to eliminate sugaring. When I first started welding kegs my o-ring would pucker but after a few you just dig in and get it done. I don't bother with dimpling either. It sounds like a sales point but doesn't do anything to help the process.

[DLewis0289]

Ok, now I am curious. All you guys that know how to weld cpgl's to beer kegs......is there a demand for this? The reason I ask is, it sounds like a perfect application for press projection.

[Poland308]

Most welders have a close relationship to beer!!

[exnailpounder]

Ok, now I am curious. All you guys that know how to weld cpgl's to beer kegs......is there a demand for this? The reason I ask is, it sounds like a perfect application for press projection.

Homebrewers always need something put on their kegs. They have weldless fittings and alot of them go that way but I have done quite a bit of it over the last year or so.

[exnailpounder]

Most welders have a close relationship to beer!!

[glassTransition]

Thank you all for the answers and recommendations. I have several spare fittings and plan to sort out as much as I can ahead of time with practice setups. I've read that the lid of the keg is thicker than the side wall. Is that everyone's experience? If so I'll have to find some 18 ga. scrap instead of using the cutout lid.

I want to be sure I understand part of the answers:

I've drilled the hole making it fit the ID of my fitting

Does this mean you attach the fitting to the outer surface instead of through it? Then you fuse the edges of the hole to the inner edge of the fitting? What if you wanted the fitting to penetrate the keg 50-50?

...with a ID purge,

I plan on using a small dam (a beer can with the top cut off! ) taped over the fitting inside the keg. The argon feed will be through a hole in the closed bottom end of the can. The fitting being welded will be taped over the outside opening with a hole poked through the tape for pressure release. Is argon flowing through the inside of the fitting what you mean by ID purge?

How do you get access inside to fusion weld the seam? I can get my arm in there OK, but what about room for one's head?

[exnailpounder]

Thank you all for the answers and recommendations. I have several spare fittings and plan to sort out as much as I can ahead of time with practice setups. I've read that the lid of the keg is thicker than the side wall. Is that everyone's experience? If so I'll have to find some 18 ga. scrap instead of using the cutout lid.

I want to be sure I understand part of the answers:

I've drilled the hole making it fit the ID of my fitting

Does this mean you attach the fitting to the outer surface instead of through it? Then you fuse the edges of the hole to the inner edge of the fitting? What if you wanted the fitting to penetrate the keg 50-50?

...with a ID purge,

I plan on using a small dam (a beer can with the top cut off! ) taped over the fitting inside the keg. The argon feed will be through a hole in the closed bottom end of the can. The fitting being welded will be taped over the outside opening with a hole poked through the tape for pressure release. Is argon flowing through the inside of the fitting what you mean by ID purge?

How do you get access inside to fusion weld the seam? I can get my arm in there OK, but what about room for one's head?

My recommendations are for not having access to the inside of the keg. If you can get inside and follow Rick H's recommendations then you have a more sanitary weld.
As I stated, I build for distillers so I have to purge the whole keg as can't get inside to do what you are planning, which will work perfectly. You might want to go with something a little larger than a beer can as the keg will heat up and the tape might release. If you are further from ground zero your tape will adhere better.
LOL, you might have a bit up trouble sticking your head inside that kegger. Thats what I deal with all the time. Fittings at the top are easy but those low ones are a bitch. Understand why I weld 1/2 couplers to the outside of the keg and drill the hole through the fitting? Then there is no inside to weld. You can just reach down in there with a grinder and polish up the inside. It is not as sanitary as welding the fitting through the wall but it eliminates having to get in there and weld round the fitting again. I just tell brewers, that they need to use a bleach solution to sanitize their keg because my way can give bacteria a hiding place in the fitting but distillers don't have anything to worry about because it doesn't matter because they are only separating alcohol. I hope that answers your questions. Oh...the whole keg is 18ga. At least every one that I have welded has been. YMMV..good luck and you can PM me if you need pics or something... One more thing...MAKE SURE you do short welds and stop and use wet rags to draw out heat or you will fry your weld area and you could get stress cracks. Forewarned is forearmed.

[Rick_H]

Thank you all for the answers and recommendations. I have several spare fittings and plan to sort out as much as I can ahead of time with practice setups. I've read that the lid of the keg is thicker than the side wall. Is that everyone's experience? If so I'll have to find some 18 ga. scrap instead of using the cutout lid.

I want to be sure I understand part of the answers:

I've drilled the hole making it fit the ID of my fitting

Does this mean you attach the fitting to the outer surface instead of through it? Then you fuse the edges of the hole to the inner edge of the fitting? What if you wanted the fitting to penetrate the keg 50-50?

...with a ID purge,

I plan on using a small dam (a beer can with the top cut off! ) taped over the fitting inside the keg. The argon feed will be through a hole in the closed bottom end of the can. The fitting being welded will be taped over the outside opening with a hole poked through the tape for pressure release. Is argon flowing through the inside of the fitting what you mean by ID purge?

How do you get access inside to fusion weld the seam? I can get my arm in there OK, but what about room for one's head?

I was assuming you had access to the inside, if not my method is not ideal. Yes you are correct about the ID purge I weld the outside with the inside of the fitting domed over and vent through the outside hole of the fitting that i have tapes over this way no sugaring occurs in the fitting or in the vessel.

I'm use to welding in a mirror and tight spots so I've figure out how to reach and weld at times holding my mask in front of me...lol Since I know where my settings need to be and I'm just fusing it together it makes it easier. Feeding filler is a whole nother issue.....

As far as 50/50 you could just weld the outside for strength but to be Sanitary the inside seam would need to be welded. So if you don't have access you would need to fit the fitting to a hole in the keg tight, then weld full penetration at the seam, harder then it sounds at times.

Exnailpounder methods will work fine if you don't have access, and drilling after the fact makes it much easier especially if you've never done this before.

So by your comments I'm assuming you have access to the inner of the keg? Are you distilling or putting a mash or something else in? It's all about preventing contamination or microbe growth..beer guys want super clean.

[glassTransition]

Thanks guys for all the info.

I'm use to welding in a mirror and tight spots so I've figure out how to reach and weld at times holding my mask in front of me...lol Since I know where my settings need to be and I'm just fusing it together it makes it easier. Feeding filler is a whole nother issue.....

I was playing with a webcam and a Shade 6 filter, but a magnifying mirror might be way easier! I have access through a 12" opening in the top, but the fitting is on the bottom so the access is limited.



I only had time to cut the top out this weekend. I will try a bunch of approaches on some samples before I decide on what will work best for me. I know I could just bang something out, but I want it to be as good as possible because I doubt this will be the last one I do and because
I think you should just do things the best you can .

I read about yet another approach that sounds promising. I made a dimple die to try it as well. The idea is to flare (dimple) the hole from inside to out and then flatten the surface of the protruding edge so you essentially have a butt joint of more or less equal thicknesses (the fitting is chamfered) of "pipe" to weld. This should also make the inside flow-out unnecessary.

This project will be used as a BK for beer so most of my sanitary goals are overkill, but it seems worth it to figure out now.

[exnailpounder]

Bring your A game on the pedal when dimpling thin stainless. Heat sink the heck out of it and post up some pics of the final outcome. Good luck.

[Rick_H]

I never tried a pull on stainless like your talking always wanted to make a setup for 1.50" which I do a lot.

Stretching 16g or 18g thinner will test your skills for sure since you'll be welding thick to thin. My only concern would be strength if any weight is applied to that fitting. You'll need your A plus game....

[glassTransition]

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Here are some cell phone shots of practice (sorry for the poor focus).

Not really too hard to control with heat sinks on the back. My A game is probably about equal to most of your C games so I'm not sure my A+ will help too much LoL!

Getting my heat set by running a bead just on the keg wall I had my max set to 70 amps and was running around 40, but when I did the actual joint with the copper and aluminum blocks, I had to turn it up to 110 and stand on it to start the puddle.

I didn't want to waste argon on the practice so the back didn't have any purge - just the sink which I think may be good enough - what do you guys think? I just hit it with a quick wire brush. I doesn't look like the oxidation (chromium whatever) penetrated at all.

I don't know that the dimple adds much, but it also wasn't deep enough to stretch to the OD of the fitting. I'm conflicted as to strength pros and cons. It will thin the material and possibly make it brittle around the edge if I go that far, but it will also make the keg wall a bit more rigid. I'm thinking now that I'll put a small hole in just for the gas to flow through and then drill and countersink up to the ID of fitting after welding as exnailpounder suggested. I have to go beyond just drilling to the ID because it's a two-way fitting and it wouldn't be possible to screw something in from the inside otherwise. It looks like the penetration will be good enough to not have to flow the inside, but if I do it should be very little heat.

[exnailpounder]

OHHH...you put the fitting on the inside of the keg! I usually put them on the outside...I guess it doesn't matter. I guess we were kind of talking about 2 different things. Your weld look fine and it looks like you controlled your heat input really good as you have decent color. I know we all strive for beauty but there is no shame in stopping and starting a weld. Welding around one of those little couplers isn't possible anyway. Nice work! Show us the final outcome and then when the word gets out you can weld fittings on a keg you'll be a busy boy

[exnailpounder]

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This is one I did. I normally cant get inside the kegger to back it up so I thread the fitting in tight up to the shoulder and then concentrate my heat on the thicker fitting and wash onto the keg wall or I just weld a half coupler to the outside wall of the keg, this is an example of both. It is not sanitary because I can't get inside but distillers don't care. I can get inside of a beer brewers keg for a sanitary weld. but not down low on the keg.

[glassTransition]

Thank you for the help. We are talking about the same thing.

I will put the final one on the outside. I just did this one inside because the Sanke thing on this lid cutout was in the way

[exnailpounder]

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Here is a slip adapter for the copper column. This is 1/4" SS welded to 18ga.
This is just to give you an idea of the difference of what I mostly deal with. This Is why I have to purge the entire keg and have to really watch my heat input...blowing holes really sux!

[exnailpounder]

Thank you for the help. We are talking about the same thing.

I will put the final one on the outside. I just did this one inside because the Sanke thing on this lid cutout was in the way

You bet! You got a fine start at it so you will be busy. If you're like me, you love the challenge.

ps...I just so happen to be enjoying some of the fruits of my labor at this very moment!

[glassTransition]

That looks like quite a trick.

Did you just feather from the thick to thin or did you use some internal sinking?

[exnailpounder]

I did feather out the bead from the thick to the thin and used filler to control the heat a bit. I would weld about an inch or so and stop, throw a wet rag on the top to draw out some heat and then weld on the opposite side. I also used a thick copper disc inside it to hold in the purge gas that also drew out some heat. The result wasn't very pretty but there was no warping or distortion or more importantly, heat cracks.
I brazed a fitting onto a keg once because I didn't have any way to purge it at the time. It came out really pretty as silicon bronze does and I even leak tested it but the owner called me about 2 weeks later and said the keg was leaking around the fitting. He brought it over and I checked it and sure enough, there were little spider web cracks in the keg wall, all around the fitting in the HAZ. You couldn't even see them they were so small so that taught me to be very anal about controlling heat on thin stainless. Knock on wood, I haven't had another one crack yet.

[glassTransition]

I wondered about using silicon bronze. Thanks for saving me the effort!

I put four evenly spaced tacks on and then welded 1/4, opposite 1/4, backstep 1/4, and then the remaining 1/4. I let it cool a bit after each section and then removed the heatsink and dunked it in water. Does that sound workable or do I need to take all of remaining heat out of the stainless too with the wet rag? I'll do it anyway BTW just to be safe, but I'm curious how much is really required?