Greetings gang! 12000 gal. gunite freeform finished January 2002. SWCG.
Have acid washer 2 or 3 times. Had the issue of calcium stalagmites growing off the walls, but always kept mu SI between the 2's.
At last years drain and was found several pop-ups in floor plaster, and chipped out bad spots on wall and patched them all, hoping to postpone replaster a couple of more years.
In the last month a rust spot appeared in a previous sound area! I was there for every concrete pour and the plaster day. I know all the rebar was properly placed and well inside the 12" thick floor, have pictures to refresh my memory.
So I found a funnel that fits in 1/2" PVC of the correct length to hover over spot from the deck and pour about a qt. of Muratic Acid directly on the spot to clean it off. Revealed a hairline crack in plaster about an inch long. But to be producing rust it has the concrete must be cracked below, correct?
So here is my plan, Loctite 82093 Underwater Repair Epoxy will be delivered today. I always have Polyethylene scraps around so I plan on cutting out a 2" disk with a hole saw and bolting it onto an approximate rod to reach the bottom, about 4' deep at the spot. My though is the epoxy will stick to the plaster easier than the PE.
Acid wash the spot like before and give the pump 30 minutes to neutralize the area. Make be up a nice wad of epoxy and push it down over crack.