Welding keeps warping the SS coupling?

[Pamulli]

I've now welded two different 1" stainless half couplings to my keg and the heat from the welder is warping them to the point where I can't thread the heating element in. I'm using a MIG welder with ER308L wire and the coupling is 304 stainless. These couplings are made to be welded so obviously it is possible.

The last one I welded I put a SS plug in it thinking it would keep it from warping, but that didn't work and now I can't get the plug out. It isn't welded in because I can get it to turn about 1/8", but that's it. Now I'm going to have to cut yet another coupling off unless I can figure out how to get the plug out which seems unlikely.

I'd like to avoid having to pay someone to TIG weld it because all the welders around me have said they have a $100 minimum, but I'm at the point where I'm ready to give up on this. I'm willing to give it one more try if someone knows of a way to weld a coupling without warping it?

Thanks

[Pamulli]

Also, I'm using .030 wire.

[Pamulli]

Does anyone know if a stainless hex locknut would work any better? I just wonder if it's shape would make it less susceptible to warping?

[rednose]

Use a reduction from 2" to 1" or 1 1/2 to 1" to weld and you'll be fine.

Man, 100$ for welding a piece, that's called stealing.

I just asked here how much it will cost to make a 250Ltr conical fermenter, material apart.

They ask for 100 USD to make it, but the whole thang.

[LWTCS]

70 dollar shop minimum in my area.

[Mud Mechanik]

The last one I welded I put a SS plug in it thinking it would keep it from warping, but that didn't work and now I can't get the plug out.

The threads are galling, before threadding in the plug dip the threads in milk of magnesia and then weld the coupling on, the plug will then come out unscaved. MM

[Pamulli]

The threads are galling, before threadding in the plug dip the threads in milk of magnesia and then weld the coupling on, the plug will then come out unscaved. MM

So you are saying to use a half coupling, but dip the plug in milk of magnesia and thread it in and weld it with the plug inserted?
Do you think using something like a bell reducer and no plug would lessen the risk of it warping?

[Kentucky shinner]

Whoom every is welding this is getting it to hot. They need to tack it in several places, let it cool, then weld a small protion then let that cool. do that until it is completely welded and it will not warp.

[ozone39]

heat the outside coupling up with a torch, then put some of that GM valve guide penetrate (or penetrol) in there, plug should come out. One question, are you welding the end of the coupling to the keg (hole is smaller than the OD of the coupling), or are you inserting the coupling into the hole than welding it? Is this a standard SCH 40 coupling for pipe, does it have a smooth out side finish (these are called a misson coupling) or does it have reinforcement ribs around the ends (these are cast s.s couplings)..

[Fastill]

The last one I welded I put a SS plug in it thinking it would keep it from warping, but that didn't work and now I can't get the plug out.

The threads are galling, before threadding in the plug dip the threads in milk of magnesia and then weld the coupling on, the plug will then come out unscaved. MM

+1 Welding a coupler with a pipe plug in it will cause galling when you try to remove the plug. Stainless is the worst for this. I use neversieze to keep the threads from sticking.

[Pamulli]

Thanks for the helpful suggestions. I ordered a 1-1/2" to 1" bell reducer and will try welding it with a plug and something to prevent galling in the threads. I'll also divide the weld up into sections to try and keep the temp down.

Welding SS and trying to get a water tight weld has proved MUCH harder than I expected.

Thanks

[heynonny]

+What Kentucky Shiner said
Sounds like too hot, plus try the 'quadrient' welding. Try fitting the 'fitting' to the keg diameter and welding together, 'then' drilling through the keg. Screw in a short piece of pvc pipe to protect the threads while doing this, , -hey-

[Pikluk]

From "ozone39" One question, are you welding the end of the coupling to the keg (hole is smaller than the OD of the coupling), or are you inserting the coupling into the hole than welding it?

which is better or the right way?

[johnhopper1957]

Couple of different ways of doing it, tac on 4 points on alternate points, after each tac cool with a wet rag till it is cold to touch before doing next tac. Once you have the 4 tacs done do alternate sides in short sections, after each section cool with a wet rag. (rag should be cotton don't use a synthetic rag)

The other way is to use a heat sink, may sound stupid and very obvious but copper is going to be the best, since you are doing a keg you could also use water in the keg but it'll generate steam depending on volume and amps.

I would go the wet rag option if I was you but your call.

Hope info is of some help.

[Pikluk]

thanks for the tip ill make sure the welder know that.

but to prepare the keg for welding should the coupling be sitting on the keg or go trough the keg?
should i make the holes smaller or bigger then the coupling?

[johnhopper1957]

Sorry missed this one, the ferrule should sit on the keg, then you'll have something under it to form the weld pool, if you have it through you would weld from the other side and it'ld be a corner joint which is really easy and neat to do, that said you can't weld from the other side because it's on the inside of the keg

Deos that make sense?

[Dnderhead]

why not just run a tap in and chase the threads?

[Bushman]

why not just run a tap in and chase the threads?

My thoughts exactly, that is what I did!

[mash rookie]

why not just run a tap in and chase the threads?

Ding, Ding, Ding. We have the correct answer. Chase the threads with a tap if the element wont screw in. Yes, four tacks and it really should not deform at all.

Welding with a plug will not keep it round. If you have to weld something with a nipple or coupler attached you have to coat it as Ozone suggested or it will always stick. Particularly with stainless. It will gall every time.

I would use a good penetrating oil and slowly and patiently work out the plug. Fifty – sixty times back and forth should do it.

I think you may have a coupler that is poor fitting to start with. I weld a lot of couplers and just don’t have any problem with being out of round. If you remember to coat with anti splatter you wont have weld berries in the threads screwing things up either.

Actually you got several correct answers from the guys. Good luck getting the plug out.

EDIT ; LOL I just realized the OP was over a year ago. He probably has the plug out bu now.

[Kentucky shinner]

70 dollar shop minimum in my area.

$90.00 here LWTCS.... that is was folks out of the country do not understand...

[acfixer69]

Old thread relived but this info in not covered in it.
Warping may not be the problem here thou it is with welding. SS 1" half couplings are threaded with NPT T= tapered. Hot water heating elements are NPS S= straight threads that is why the O ring on the flange. Pipe tape will work/help but is still wrong. taping the half coupling to a NPS is the correct way.

AC

[mash rookie]

Old thread relived but this info in not covered in it.
Warping may not be the problem here thou it is with welding. SS 1" half couplings are threaded with NPT T= tapered. Hot water heating elements are NPS S= straight threads that is why the O ring on the flange. Pipe tape will work/help but is still wrong. taping the half coupling to a NPS is the correct way.
AC

Another great point. Most people don’t know that there is NPS or the difference between the two.
The NPT coupler when cut in half usually will accept the NPS water heater element with no problem.

I have a couple of NPS dies and even they are tough to come by. My machine shop supplier has to order them for me.

(I don’t even want to know about IPT)

[johnhopper1957]

70 dollar shop minimum in my area.

$90.00 here LWTCS.... that is was folks out of the country do not understand...

I welded a ferrule on a keg last night for a fella for $20.00 and I ended up supplying the ferrule so $10.00 for the welding I suppose ............ Charging someone min $70.00 or $100.00 min is a big money maker for them. Then again I make stuff for a hobby not to make a living out of it.

[Prairiepiss]

70 dollar shop minimum in my area.

$90.00 here LWTCS.... that is was folks out of the country do not understand...

I welded a ferrule on a keg last night for a fella for $20.00 and I ended up supplying the ferrule so $10.00 for the welding I suppose ............ Charging someone min $70.00 or $100.00 min is a big money maker for them. Then again I make stuff for a hobby not to make a living out of it.

You don't have the overhead they do. We charge $95 an hour. Weld shops are right there with us around here. But if I'm gona pay $95 an hour. It better be one hella stack of nickels. Because I can Bubblegum it myself.

[johnhopper1957]

70 dollar shop minimum in my area.

$90.00 here LWTCS.... that is was folks out of the country do not understand...

I welded a ferrule on a keg last night for a fella for $20.00 and I ended up supplying the ferrule so $10.00 for the welding I suppose ............ Charging someone min $70.00 or $100.00 min is a big money maker for them. Then again I make stuff for a hobby not to make a living out of it.

You don't have the overhead they do. We charge $95 an hour. Weld shops are right there with us around here. But if I'm gona pay $95 an hour. It better be one hella stack of nickels. Because I can Bubblegum it myself.

That is true