Peel Stop & Concrete Bonder - are they the same chemical?

I am getting ready to paint the stucco on my old house. It's been painted before, and that paint is peeling in many spots. I cannot remove all the peeling paint without destroying the texture of the stucco, so I was planning to saturate the cleaned & (lightly) wire brushed surface with Peel Stop, but it is now $24/gallon. That seems pricey for a product that looks and smells like watered down white glue. And this project - done right - will take many gallons. The other day I saw concrete bonder (described on its tech data sheet as ethylene polyvinyl acetate co-polymer) for about half the price of Peel Stop, and wonder if I can use it in place of the Peel Stop. (The bonder carries a further economic bonus - to be water thin like Peel Stop, so that it can crawl behind my peeling paint, I will need to cut the bonder 50:50 with water.) I have done a couple one-foot-square tests of the bonder - and Peel Stop, then painted them with my house paint, and so far can see no difference. Both have adhered very well. But I have no way to simulate the effect of years of exposure, or a month of rain.

Does anyone know if there's an actual difference - other than the concentration - between the two chemicals? Please don't just quote from the labels, or the Tech Data sheets, as I have read those.

 

I don't know how the bonder compares to Zinnser's PeelStop. I've painted a lot of stucco and/or block houses over the years and have never known of any product to do a good job of sealing a loose coating to the substrate. What I would do would be to scrape and pressure wash the stucco to remove as much loose paint as possible, then address the texture differences. That would be the only way to garuntee a lasting paint job.

I've never used PeelStop on the exterior but it does work well on interiors where it isn't feasible to remove all/most of a failing paint job. $24 isn't a bad price for that type of primer.