Welding Tips and Tricks

There has been a little interest in welding on kegs so I thought I would post these pics of a project I am working on right now. That big thick ring on the top of the keg is a custom column adapter that is 1/2" thick. It wasn't supposed to be that thick but my machinist went crazy on me . It also wasn't supposed to be 400 series or have a beveled shoulder either but nothing a little 309l didn't fix. Welding 1/2" thick to 18ga. is a little hairy. I stop after about welding an inch or so to heat sink so I can't make the welds really pretty The smaller fitting is where a thermometer will go. The bigger fitting welded to the keg is to cover the bung hole. The keg is purged with whats left in that 300cf argon bottle in the background. This is a essential oil extractor and is shown for demostration purposes only. I will post up the finished project.

Thanks for posting. That looks like a real mismatch in thickness. Must have been a bear.

Did you patch the top? There looks to be a boomerang-shaped piece added on.

Have you ever cut a cross-section and etched it to see how well the fillets penetrate when done from the outside only?

Montell Jordan said it best. "This is how we do it", looks good!

glassTransition wrote:Thanks for posting. That looks like a real mismatch in thickness. Must have been a bear.

Did you patch the top? There looks to be a boomerang-shaped piece added on.

Have you ever cut a cross-section and etched it to see how well the fillets penetrate when done from the outside only?

That boomerang shaped thing is an asset tracker. The brewery welded those on to deter thieves. I have never gone as far as to check penetration because all I am looking for is my welds to not leak. There is no pressure involved so as long as she holds water and there is no sugaring, all is good. The 1/2" thick ring was easier than I thought but my crazy machinist put a bevel on both shoulders which opened up that filet so I was worried about blowing holes but it came out ok. Lots of starting and stopping to cool things off but thats the game.

I'm surprised nobody has come up with an electric (like spot welding) jig for these fittings. It seems like it could be done and it would be perfectly clean and very little skill required.

Have you every tried to autogen weld a mismatched joint like that? I've found that you have hold the arc on the thick stuff until it puddles some and then wave over the thin and back to the thick over and over until it flows - like a tack. Is there another way to do it?

They have, it's called press projection welding. Most people can't afford a welder that can supply 80,000 amps.

My little foot-operated 110 VAC spot welder will fuse a 0.250 inch diameter spot. That's ~.05 sq inches at 15 Amps (primary side) give or take.

The area of the joint of a 1" diameter fitting through 18 ga (0.048 thick) is ~3 x 0.048. So would it only take 45 Amps to get the same current density? Why 80,000? I know there are differences in heat transfer and many other variables, but....

glassTransition wrote:I'm surprised nobody has come up with an electric (like spot welding) jig for these fittings. It seems like it could be done and it would be perfectly clean and very little skill required.

Have you every tried to autogen weld a mismatched joint like that? I've found that you have hold the arc on the thick stuff until it puddles some and then wave over the thin and back to the thick over and over until it flows - like a tack. Is there another way to do it?

Thats exactly what I do. I use a little filler to reduce undercut on the thicker metal and control the heat of the puddle but it really isn't necessary as in autogen. Since I have to stop so often and can't really make the welds as pretty as I want to at least I can control the undercutting.
If you look at kegs, they are all robot welded and they may come up with a process to spot weld fittings on but from the factory a stock Sanke keg only has one fitting so I don't think it would be a viable way to put the spear fitting in.

When they weld couplings like this in industry (actually called "spuds") They will put it in basically a large press with copper tooling, place the spud under pressure and run high current through it causing it to heat and go into "upset". The entire weld only takes around 6 cycles. One example in industry is water heater companies. They will weld the heavy couplings to the thin tank wall using this process.When done effectively you can thread a pipe into the coupling and pull 100% parent metal around the weld (very good weld). It is in the resistance welding family. I have designed and built welders that can get to a steady state current of 150,000+ amperes.

The only problem with the keg is you would have one helluva a time getting the bottom platen in the keg without cutting the bottom off of it.

https://www.youtube.com/watch?v=krbr7od4Cgk

jeff
have you ever thought of making a platform
to set the keg on that would allow you to move
around it rather than having to reposition it.
or some type of lazy susan...
seems like you do a lot of these..
craig

motox wrote:jeff
have you ever thought of making a platform
to set the keg on that would allow you to move
around it rather than having to reposition it.
or some type of lazy susan...
seems like you do a lot of these..
craig

craig....I gave up on making anything helpful I have made so many purge boxes and specialty clamp devices and I end up canibalising them for parts so I take the hard road I usually just have short 2x4s on my table to prop on and I just use them to support the keg while I work. I probably make it sound like more work than it actually is but it's not bad working with kegs. I have done so many I just have my way of doing things that works for me. If you saw my scrap pile you would laugh. People always ask why I have so many half-done projects in my scrap pile and my response is that they were done but I needed something off it so I tore it apart It's not easy being me

eople always ask why I have so many half-done projects in my scrap pile and my response is that they were done but I needed something off it so I tore it apart : It's not easy being me

god i know how that works........

Looks good!

I laugh at the fixture thing because I go through it also. I see all these guys doing flanges and pipes with a positioner so of course they are perfect.

Not sure where those jobs exist for the most part I'm always out of any normal position, crinkled in my neck, sore lower back. However for some reason I still want to build one...lol