The Great Bottle Opener Giveaway

Home Brew Forums > Home Brewing Beer > DIY Projects > Calling all stainless welders/experts

Reply
 
LinkBack Thread Tools
Old 11-06-2012, 08:21 PM   #1
jcaudill
Feedback Score: 2 reviews
Recipes 
 
Join Date: Dec 2010
Location: VA Beach, VA
Posts: 818
Liked 53 Times on 39 Posts
Likes Given: 4

Default Calling all stainless welders/experts

I need opinions from anyone well versed in stainless and particularly welding.

I had a local welder weld some fittings into new 100 quart update international pots. The first contact with water was when I was passivating them early October. I used about a 3% concentration of nitric/phosphoric acid. - Loeffler KMS-10 which is formulated for this. I noticed almost immediately after finishing the passivation and flushing that every weld, particularly where ground, was developing what appeared to be rust. When I got home I tried to scrub the heck out of all the areas with Barkeeper's Friend. At first this seemed to work. But I'd come back the next day, and the rust would be right back.

So after some reading, I found out the most likely scenario is that they introduced steel somewhere along the lines. Probably the grinding wheel - or maybe a brush. I also read the only way to fix this is chemically - that no amount of mechanical treatment will solve it. So I decided to run KMS-10 straight - which is basically around 40% phosphoric acid, and 15% nitric acid. All the reading suggested this combination should take care of removing the iron. So I decided to do a test soak - I soaked it for about 50 minutes. At first it was very promising - I saw no signs of rust. But after I got all the acid out and flushed it well, about 5 minutes and this is what I saw:



If my eyes aren't deceiving me, I see pitt corrosion. And not to mention it took almost no time for the rusting to start again. Anyone else agree with this? Any other comments on anything else I can try? At this point I'm close to throwing in the towel and calling the pots unusable. Just to reiterate - the pots have never been used!

Thanks in advance.

__________________
jcaudill is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 08:30 PM   #2
CoalCracker
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
CoalCracker's Avatar
Recipes 
 
Join Date: Sep 2009
Location: Macungie, Pa
Posts: 1,588
Liked 100 Times on 63 Posts
Likes Given: 35

Default

Is that the backside of the weld? If so, they didn't back gas which caused the sugaring you see. There may be some spots in there that didn't passivate. He didn't happen to clean the area with steel wool or a wire brush did he?

I wouldn't call them unusable.. Clean it up before a brew, brew, repeat.

__________________

coalcrackerbrewing.blogspot.com
Vintage Kegerator Build
1 BBL Tippy Dump

CoalCracker is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 08:41 PM   #3
jcaudill
Feedback Score: 2 reviews
Recipes 
 
Join Date: Dec 2010
Location: VA Beach, VA
Posts: 818
Liked 53 Times on 39 Posts
Likes Given: 4

Default

Yes it is the backside of the weld.

I think it would be impossible for any of those spots to not have been passivated because I had the entire area soaking under acid for 50 minutes.

Honestly, I have no idea everything they did. The problem is - it takes an enormous amount of effort to make it go away. I can't just lightly scrub it, I have to scrub the hell out of it. And in a matter of minutes, it's back. I'm not so sure I am willing to go through that every brew - and I shouldn't have to.

Here's the before pic - I'm wondering if by tomorrow morning it'll look like this again.

__________________
jcaudill is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 08:52 PM   #4
mattd2
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2009
Location: Papamoa, New Zealand
Posts: 3,355
Liked 233 Times on 190 Posts
Likes Given: 41

Default

What we need is for someone with experience in Stainless welding to write a spec for welding couplers onto kegs that we can all take to the local shop and say "Can you do exactly what is on this sheet and if you can't/don't I will not be paying you"
Looks like you are correct with they have contaminated by using a tool used with mild steel to grind back/clean up the welds. Chemical solutions can only clean up the free iron on the surface, if it has been embedded into the stainless you are in for a battle.
Have you spoken to the shop that did it? If they have used the wrong disc/flapper wheel on it they should take care of it, I would guess if it was a reasonable sized shop with an apprentance it would have been given to him and he might of messed up.
Did a quick search and found a bit of insight http://www.finishing.com/79/21.shtml

mattd2 is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 09:22 PM   #5
jcaudill
Feedback Score: 2 reviews
Recipes 
 
Join Date: Dec 2010
Location: VA Beach, VA
Posts: 818
Liked 53 Times on 39 Posts
Likes Given: 4

Default

I have to admit, I'm pretty bummed! My luck with local welders has been, well, unlucky. What particularly pi**es me off about this one is I specifically asked for restaurant quality welding and they said that they've had experience with it. And they were even recommend by another welder for the same thing!

__________________
jcaudill is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 09:36 PM   #6
eastoak
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jan 2011
Location: oakland, california
Posts: 3,180
Liked 144 Times on 136 Posts
Likes Given: 83

Default

i must be lucky, never even knew there was anything special about welding stainless. my kegs have not had any of these problems after having couplers welded on.

__________________
eastoak is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 09:50 PM   #7
Cromwell
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2011
Location: Thousand Oaks, CA
Posts: 772
Liked 72 Times on 59 Posts
Likes Given: 132

Default

Just my opinion, but that is a spectacularly poor weld just to start with. I'd go back to the shop and show them a "real" weld, and show them the rust, and ask them to make it right.

__________________

Primary: Beer / Secondary: Beer / Lagering: Old beer.

Cromwell is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 10:01 PM   #8
jcaudill
Feedback Score: 2 reviews
Recipes 
 
Join Date: Dec 2010
Location: VA Beach, VA
Posts: 818
Liked 53 Times on 39 Posts
Likes Given: 4

Default

I can't say I disagree. But the thing is I need to be armed with both information on why it's a poor weld, and possible solutions. The thing is - I don't see any viable solutions right now. If chemicals can't fix it, ???. That's why I'm here. I need to hear from others with more experience.

__________________
jcaudill is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 11:33 PM   #9
Rbeckett
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Rbeckett's Avatar
Recipes 
 
Join Date: Dec 2011
Location: Bronson, Fl
Posts: 984
Liked 63 Times on 46 Posts
Likes Given: 29

Default

Those welds are definately poor quality and lack fusion. The sugaring is caused by not having shielding gas on the back side of the weld. I would return it to where they attempted to weld it and demand they replace my brand new kettle. I would then take it to a real welder and tell him or her exactly what I want. There is a WPS (Welding Procedure Sheeet) for welding stainless and if followed you will never have a problem, if not you will have nothing but problems as long as you have that vessel. On that type of item the welds should look like a stack of dimes laid on edge and be of uniform depth and equally spaced. I'm not seeing anything like that in any of the pics you posted. I would have gotten fired for turning out some junk like that.. Oh, and I welded for a living for a good few days before I got disabled and had to medically retire.
Wheelchair Bob

__________________

What do you mean "no Kidneys"???, WTF now I gotta drink less beer...
Join the Automation sub forum in Electric brewing for a discussion of components and control systems. I did!!!!

Rbeckett is offline
 
Reply With Quote Quick reply to this message
Old 11-06-2012, 11:35 PM   #10
Junkster
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: North Central, Ohio
Posts: 508
Liked 30 Times on 21 Posts
Likes Given: 3

Default

If you have a disc grinder, I think you could clean this up fairly well with some flap discs and then some abrasive pads. You may have to finish by hand with some abrasive pads and then clean and passivate. I finished the back side of these welds that way after not getting a good back purge of argon on them.....

kettleinside08r.jpg.jpg  
__________________
Junkster is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Calling all DFW all grain brewers. Or welders. stadtbrau Equipment/Sanitation 3 11-17-2010 03:21 AM
Calling all Experts blackntan Beginners Beer Brewing Forum 9 02-24-2009 04:21 AM
Calling wine kit experts KENfromMI Wine Making Forum 10 09-06-2008 12:49 PM
Calling all exhaust experts dblvsn Equipment/Sanitation 6 03-26-2008 05:02 AM
Calling all Refrigerator Experts jfrizzell Equipment/Sanitation 9 09-24-2007 02:03 AM