I did not test until the joint broke. My clamp was getting to the point that I did not want to flex it any more, so I quit the test at 104 lbs.
Yes, 104 lbs. That is 52 lbs per linear inch.
Since the sink is roughly 15 x 22, that means I have 2 sides that total 30", and the long sides total 44". Added together, we've got a total of 74 linear inches to split up the weight of the water to.
Even IF, I could fill the sink to 10" depth all the way around, (I can't because only 1 corner is that deep, while the shallow end is about 8") we can figure a couple of things.
15 x 22 = 330 square inches - not accounting for round corners. Then we can multiply by 10 for height, which will equal 3300 cubic inches.
There are 231 cubic inches in a gallon of water, so, 3300 / 231 = 14.28 gallons of water, times 8.33 lbs per gallon.
So, 8.33 lbs x 14.24 gallons = 119 pounds. If that is split up equally between the linear inches of 74, we only come up with 1.608 lbs per linear inch.
Since I just tested the wall to bottom glue joint at 52 lbs an inch, it looks like that joint should be fine. Again, that would be in a worst case scenario, with the sink completely full with a depth of 10 inches of water.
There was no fiberglass nor epoxy with what I tested, just wood and glue only. Fiberglass mesh and epoxy would increase the strength of the joint as well.
If I am missing something, please let me know.
Also, thanks for bringing the subject up about the strength of the sink. If you had not, I never would have tested this, and wouldn't know the numbers.
