Screwed up welding

[Islandboy85]

A guy I know welded my kegs. One of the fittings is full of slag on one edge like he burned through it a bit. Is it possible to repair female pipe threads or am I screwed? If you cant fix it, how would you suggest I get the fitting out and a new one welded back in?

 

[Thirteen]

Just get the right size pipe tap and chase the threads, Use plenty of tapping fluid.

 

[wilserbrewer]

You can chase the threads w/ a tap. Or simply attempt to thread the fitting in...one trick is to cut 2 or 3 lengthwise grooves w/ a hacksaw into a spare male fitting or a bolt to make a "poor mans" tap.

 

[Schlenkerla]

Just get the right size pipe tap and chase the threads, Use plenty of tapping fluid.

+1 Try this. Don't skimp on the lube though. Go easy on the tap too. I have fixed buggered up threads with a tap or die set.

 

[GreenMonti]

I am not so sure I agree with the idea of using a plug as a tap. I do however agree on the use of lube and plenty of it. Stainless likes to seize up when put under pressure. The heat generated will lock things up right before you know it. Good luck. I hope it works out for you.

 

[Schlenkerla]

You can chase the threads w/ a tap. Or simply attempt to thread the fitting in...one trick is to cut 2 or 3 lengthwise grooves w/ a hacksaw into a spare male fitting or a bolt to make a "poor mans" tap.

I think this would work if the foul up is not too bad. But you gotta mess up a SS fitting to do it.... I'd get the real thing first or ask to borrow one.

 

[lanvp]

Just get the right size pipe tap and chase the threads, Use plenty of tapping fluid.

I agree with your suggestion. I had a similar issue and fixed it with a tap. It took some "persuasion", lots of tapping fluid and some leverage (I use my ratchet breaker bar)!

Oh, one more suggestion, once in a while back the tap out to make sure the flutes are clear and to add more tapping fluids...

Good luck!

 

[Thirteen]

You can chase the threads w/ a tap. Or simply attempt to thread the fitting in...one trick is to cut 2 or 3 lengthwise grooves w/ a hacksaw into a spare male fitting or a bolt to make a "poor mans" tap.

I'd be far more comfortable doing this on carbon steel than stainless. Even with the grooves you're deforming the damaged threads more than you are cutting them. With stainless the risk of galling and a seize up is just too high.

Use a good sharp tap. Lots of fluid. Back the tap off 1/2 turn to break chips every so often. DO NOT try to power through it. If you can't go forward go backwards. There have been plenty of internal stainless threads I've had to repair an 1/8th of a turn or less at a time (usually smaller sizes though where breaking the tap is a concern).

 

[Islandboy85]

Thanks guys. One more thing' I leak tested the kegs last night, dried them out well, but this morning when I put my false bottom in I saw te inside of the fitting was rusting. He only welded the outside and told me it would be fine that way, but the inside was all jagged from welding. Do your kegs do that too?

 

[klyph]

Sounds like he didn't back gas or flux the inside of the weld. That part is now no longer stainless

 

[Islandboy85]

Can I have the inside wire brushed and welded with flux to fix this?

 

[klyph]

The process you are looking for is call re-passivisation and there are multiple ways to accomplish it.

Can you post some pictures so we can better see what happened?

 

[Islandboy85]

http://emob924.photobucket.com/albums/ad81/islandboy85/SU1HMDAwMTktMjAxMDA0MTQtMTQzNS5qcGc.jpg

 

[Islandboy85]

http://emob924.photobucket.com/albums/ad81/islandboy85/SU1HMDAwMTctMjAxMDA0MTQtMTQyOC5qcGc.jpg

 

[Islandboy85]

http://emob924.photobucket.com/albums/ad81/islandboy85/SU1HMDAwMTYtMjAxMDA0MTQtMTQxMC5qcGc.jpg

 

[Islandboy85]

http://emob924.photobucket.com/albums/ad81/islandboy85/SU1HMDAwMjAtMjAxMDA0MTQtMTQzOS5qcGc.jpg

Sorry these are on separate posts. It's how I had to do it from my phone. You can see how bugged up my kegs turned out

 

[klyph]

 

[klyph]

Ya, didn't back gas the weld and it's contaminated.

Research re-passivisation and find the option that's best for your budget/ability/availability.

 

[brewmonk]

acid wash and re-passivate. (maybe hit it with a scrungee.

 

[schmagy]

acid wash and re-passivate. (maybe hit it with a scrungee.

I agree, polish the schit out of it with a scotchbrite pad and follow up with a strong acid wash. Well polished will help a lot. Dont use any carbon steel wool or equiv. The carbon steel will embed in the ss.

 

[Islandboy85]

Should I have the inside welded to clean it up since it's so jagged or use a grinding wheel to flatten it? Also, is repassivating a DIY thing or should I have it done by a pro? Oh yeah, pic one and four show you how bugged up the threads got...

 

[klyph]

I would think that grinding it down to fresh metal would work, but I'm not sure on that.

 

[samc]

Looks worse than the crap job my moron welder did. I tried grinding down but it is really hard to get at most of it unless you have the right tools and are skinny with a good back. I just scrubbed with bar keepers friend, left a layer of paste on it for a few days and it's mostly good. The bumps should not be of concern as you are boiling the wort.

 

[Islandboy85]

Paste? Are you talking about the flux paste like used for sweating pipes?

 

[klyph]

Paste? Are you talking about the flux paste like used for sweating pipes?

I believe he's talking about making a paste from Bar Keeper's Friend.

 

[GreenMonti]

Paste? Are you talking about the flux paste like used for sweating pipes?

I believe he is talking about a paste of bar keepers friend?


Welding over the sugar isn't going to really help. If the front isn't purged when this is done it will just push it right through and then it will be on the front side. Plus welding down inside will be a real PITA. Lots of patience, gas, and dexterity with the torch are needed. If it did work you would just have brittle contaminated material. Take your time with a dremel tool and the sanding drums to get in close. You can use a large grinder and a flapper wheel to get the big stuff out of the way fast. If you have air tools, a small 90 would be nice in this situation.

I myself would use a carbide bit to get things down and where I wanted them. If your worried then go over it with fresh sanding drums to remove any possible surface carbon that might be there. The thing with carbides though is, they don't go away when you use them. They cut the material your removing, so its not really like using a grinding/sanding pad.

I would make sure that what ever you use is new or has never been used on carbon steel. I kinda get the feeling that the wire brush that was used was either not SS or, was a used SS brush which was contaminated. The reason I say this is cause it looks to me like you have some rust outside the weld area. Like where one would be brushing. "IF" the area I am talking about was rusting due to the heat, I would think it would be worse out and around the weld area. (the heat affected zone)

Good Luck.

 

[Islandboy85]

Ok, I'll give it a try...pray for me guys

 

[Islandboy85]

I was.able to clean the welds up some last night with a 1/8 in burr and a Bright Boy. Still needs some work.

 

[bbbrew]

Greenmonti made some really good points. I went at my first weld job not thinking about contamination and wished I had. After the fact I wish I'd had bought some new disk pads and did as little as possible. One of the other guys talks about cleaning up your kegs with a Gator pad from Lowe's. I can attest to how well they work. Before you use it on the outside, use the brand new one (fine) on the inside. It should clean up pretty good. Hopefully there isn't alot of carbon imbedded into the stainless at this point.
Good luck,
BB

 

[bbbrew]

Looking at your pictures 3 and 4, are you sure your couplers are stainless? There's a lot of rust on the surface of the coupler and inside the threads. I'm not a metallurgist however I would suspect some deposits of iron there to have that much rust develop.
You might be able to coat the surface with gasket grease to try and retard oxidation during storage.
my 2 cents.
BB