Tried a new release agent on a big pour, totally botched the finish

Last Tuesday on a 40-yard slab in Tacoma, sprayed this cheap soy-based release I grabbed from a supplier, and it left these weird oily blotches that wouldn't take a trowel no matter how long we waited. Had to grind down three sections and recoat the whole thing, added like 5 hours to the day. Anyone else had luck with a release agent that actually works on hot weather pours without streaking?

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the_sarah13d ago

That oily blotch thing you hit, I've seen it happen when the soy mix separates in the heat before it even hits the form. The carrier evaporates too fast on hot concrete, leaving the oil behind to sit on top. I switched to a linseed and mineral spirit blend I mix myself, but the trick is to let it sit in the sun for an hour first and stir it right before spraying. Also, you gotta double coat the corners and edges, that's where the streaks always show up first. Between that and keeping the sprayer low, I haven't had to grind a slab since last summer.