welding a locknut onto a kettle

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paledragon

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so i bought an NPT coupling off mcmaster and planned to have it welded onto my kettle. however, whether or not the elements screw in enough seems to be hit or miss. i just got some of the stainless locknuts from bargain fittings, and all the elements i have screw in nicely. is there any downside to having one of the locknuts welded on instead of the coupling?

thanks,
p.d.
 
I have what looks like the same nut as listed on Barging Fittings and plan to weld it to the outside of the keg. Right now I am using it weldless to hold my element on. I plan to have the gasket groove facing the element. I do not see why it will not work. I originally wanted to use a coupling but that will require me to make some other changes to my setup.
 
If you are going to weld, weld on a coupling!

the problem is the NPT coupling and the straight threaded heater elements. sometimes they play well together, sometimes not. the locknut is almost the size of a half-coupling on it's own.

have you had luck screwing elements into the couplings?
 
Both of my elements on my HLT are screwed into a 1/2 coupler that I welded into place. They don't really feel like they work well together, but they do. Also I have since burned up one of my elements and had to remove and reinstall one, and it worked out just fine. I would go w/ the coupling myself.
 
I assume you have to be liberal with the thread sealant or teflon tape. NPT and NPS sorta sometimes mesh, but I doubt it would be leak free with no sealant.

If I were doing it, I'd be silver soldering the locknut to the kettle.
 
I have 2 pots with 1" couplings and have no problems getting the elements in and out. Is there enough thread on a locknut to prevent leaking?


The nut has a groove on it for a o-ring. I think it will work. Time will tell ..LOL
 
The locknuts I sell will fully thread. And they will thread in either direction all the way down the thread.

Thread sealant should be used but the gasket/o-ring is what forms the seal.
 
i guess i was a little vague on the original post. i want the o-ring/gasket/whatever you want to call it to make the seal, not the threads like a typical male and female NPT seal.

i'm having the welding done by a welder, not myself. all the posts i've seen here have only mentioned welding on NPT couplings for the elements, never a locknut. i'll be the guinea pig on this one and try having the locknut welded onto the kettle.

thanks to everyone for all the input. i'll be sure to post back with the results. not sure when i'll have a chance to bring the kettle to the welder, so it might be a few weeks.

p.d.
 
The only issue I see is that a locknut will be easier to overheat and warp when welding it. The coupler will be more forgiving. Since you're using a welder do the work, I hope he'll know that. Other than that, I don't see an issue.
 
things appear to have gone well. minimal to no warping on the locknut. a little warping of the kettle, but it also could've been from them flattening out the area to make the welding easier. leak tested with hot tap water until i can wire up the element. goodbye propane :)

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No back gas or flux huh Yuri? It's not pretty but I'm sure it will be fine. It's not a conical.

Now that I know silver solder works like butter, I won't be soliciting welders anymore because they overcharge and under perform 90% of the time.
 
Now that I know silver solder works like butter...

Yea, I too was also really impressed w/ some of the things I've seen done w/ silver solder. Got any pics Bobby? Do you use a standard propane torch? I've read mixed things as far as the melt point of the different silver solders available, and am curious as to the "butter" procedure.
 
I hope you didn't pay for that...

nope. it was free.

i'll probably pick up an aluminum oxide grinding stone for my dremel and neaten things up, unless you think that's a bad idea.

ironically, after i dropped it off, i found the threads on silver soldering. anything else i do will be that route.

p.d.
 
No back gas or flux huh Yuri? It's not pretty but I'm sure it will be fine. It's not a conical.

Now that I know silver solder works like butter, I won't be soliciting welders anymore because they overcharge and under perform 90% of the time.

Boy that's putting us all in one basket under perform 90 percent. That hurt, I don't know what you have on the right coast for welding. Not a welder by trade just a retire engineer but I do a lot of sanitary tig welding for brewers in the KC area. I charge 12.00 for a 1/2 coupler sanitary tig welded and I furnish the coupler. 15.00 dollars for a 1 inch half coupler also sanitary tig weld and I furnish the coupler. Overcharge I don't think so.

Here is what I do for a 1/2 full coupler.
1. Drill a 1 inch hole
2. Most coupler run about .125 over one inch so I turn down on the lathe half its length to one inch strong.
3. I back flow with argon in a dam on the back side of the weld while weld the front side this gives a smooth inside.

About the same process on 1 inch half couplers.

Just a word of advice when you go to a welder ask to see his work. Any worth there salt will be happy to show you. Also ask about back flowing the weld if they don't know hit the road.

Dominus Vobiscum

Swagman:cool:
 
All we have around here are large scale shops doing either major structural or high sanitary medical stuff. It's not that they can't do a good job obviously, but they either don't want the small job or just do it quick and dirty. I should have been more clear that this was just my experience locally.
 
All we have around here are large scale shops doing either major structural or high sanitary medical stuff. It's not that they can't do a good job obviously, but they either don't want the small job or just do it quick and dirty. I should have been more clear that this was just my experience locally.

that pretty much sums up the boston area as well. given it was a freebie (friend of a friend), i'm hard pressed to complain. i doubt i could find anywhere else that was much better even if i paid for it.

p.d.
 
that pretty much sums up the boston area as well. given it was a freebie (friend of a friend), i'm hard pressed to complain. i doubt i could find anywhere else that was much better even if i paid for it.

p.d.

For a large area such as yours I don’t think you lads know where to look. Instead of looking at a welding shop look under fabrication shops. Another lead is ask at any speed shop, or race shop for welding especially Tig welding. I know there are the small shop’s out there that are always looking for any business. Right here in KC Ks. Area which is heck of a lot smaller than yours I know of least ten shops some good and some so so but a couple that are great. I do this as a hobby and try to help where I can and no I’m not one of the great shops. Been doing my own work for years and have the tools to do the work. I like things to last and work they way they should and rather do it myself. So ask around, they are out there just got to know where to look.

Dominus Vobiscum
God Bless
Swagman
 
I called about 16 places including welding shops, fabrication, railing fabs, speed shops, etc. Most of them said they have a 4 hour minimum at $75-90/hr. The one place that quoted me a reasonable amount to weld my kegs told me they could get to it in two days. After 8 days of daily calls, I went back to pick up my untouched kegs. They prioritize based on what customer needs what and the 500k$ accounts don't wait. I FINALLY found a custom motorcycle fab shop like OCC that has a guy come in twice a week nights with a TIG machine. Even that guy welded with the back unprotected.

If I ever have a couple hours worth of welding to do in the future, I'll probably buy a used TIG machine and go into business fabbing kegs on the weekends.
 
Silver soldering is as easy as soldering. Clean the joining surfaces, apply plenty of flux, heat indirectly so you don't burn off the flux, apply solder when it's hot enough to melt it. I use the Mapp gas tank on a propane torch. It burns a little hotter than propane. I bought a kit called Dyna-Grip 430 but the Stay-Brite kit is cheaper. In any case, it MUST have a flux that works with stainless and you want Cadmium free silver solder.
 
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