Stainless Steel Sink Cut and Welded together for Marijuana Grower

[Don52]

Here in Michigan we legalized Marijuana recently. My customer previously was growing Marijuana for medical use and now he is expanding his operation for recreational use. There is currently a lot of profit in growing Marijuana. Somehow they wound up with a ten foot restaurant quality 304 stainless sink that was too long to get down the stairs to the nursery, so I cut it in half and welded it back together once it was moved back to basement.

1. Ten foot sink


The first step was to fabricate an Aluminum back up bar to trap the Argon and to minimize oxidation (sugaring) on back side of the weld joint. The next three pictures show clamping pieces of Aluminum angle to the bottom surface at the rear of the sink and tack welding it together.

2. Back up on rear of sink 1


3. Back up on rear of sink 2


4. Back up on rear of sink 3


The next pictures show clamping pieces of Aluminum angle to the bottom surface at the front of the sink and tack welding it together. I turned a bar of aluminum to fit into the round edge of the sink.

5. Back up on front of sink

[Don52]

Here is what the entire back up bar looks like.

6. Entire back up bar


Here are two close up pictures of the welds, because this is after all a welding forum.

7. Weld on back up on rear of sink


8. Welds on back up bar on front of sink


I used my Matabo 6" angle grinder with a super slicer plus abrasive cut off wheel to cut the sink in half.

9. Sink Cut in half


Next we stuffed Aluminum foil in the cracks in an attempt to keep the Argon from leaking out.

10. Stuffing Aluminum foil in cracks

[Don52]

We supported both ends of the sink on their legs and we supported both sides of the middle of the sink with two service jacks. Here is a picture of the sink tack welded back together

11. Sink tack welded together


Here is a close up picture of two of the tack welds.

12. Close up of two tacks


My customer asked me to continuously weld the halves together, but asked me to leave the weld as it was without dressing.

13. Close up of continuous weld


Here is a picture of the sink back together.

14. Sink welded back together


-Don

[Ltbadd]

Interesting project, so how did the backup perform?

[Don52]

Interesting project, so how did the backup preform?

The back up Aluminum frame had three purposes:

1. Minimize oxidation of the back of the weld.
2. Act as a heat sink to pull some heat from the weld to prevent the weld from getting too hot.
3. Prevent the stainless steel from dropping out of the joint.

1. Oxidation
The front side of the weld was fine it was silver or straw colored.
The back side had a more oxidation then I would like, because I wasn't able to properly seal the edges of the Aluminum angle.
To seal the edges of the Aluminum angle it is necessary to reach up in a 1-1/2" space about 20 inches, which is very difficult.

2. Heat Sink
The Aluminum frame would have been a better heat sink if I could clamp the frame to the sink all the way across.
Unfortunately this was difficult because of the reach necessary to clamp the frame in the middle of the weld joint.
I think that it helped, but I was a little disappointed in its performance.

3. Weld Dropping
The frame was totally effective in preventing the weld from dropping through.

One comment from the Welding Web Forum suggested taping a 2" wide piece of cardboard to the back of the weld. The cardboard should be folded to create a peak that would allow some space between the cardboard and the stainless steel sink. You could feed Argon from one end of the cardboard pipe and punch a hole in the other end to allow the air to be displaced by the Argon. The first problem with this approach is that there is only 1-1/2" space for the cardboard between the sinks and it would be difficult to tape any width cardboard in that small space that is 20" deep. I believe that the geometry that we had to live with made it difficult to protect the back side of the weld.

[Electric4Life]

The back-up was a good idea in theory. Not enough material to adequately consume enough heat, however it did its job.
The panels at the joint had plenty of rigidity to them created by all the geometry. The support wasn't that necessary to minimize distortion. Of course this was just a one time gig so no need in any regrets.
My approach would have been to back purge (a trailing cup from the backside held over the weld puddle by a second set of hands. No filler, all autogenous. After the panel was cool I would come back and add filler at each end of the seam.
Keep in mind, you did the job and it turned out great, thanks for sharing!