About 30 years ago I was directed to mix liquid latex with Quikrete®️to fill an large expansion gap in a basement concrete floor prior to overlaying carpet. This would allow a firm but flexible base underneath the carpet for expansion or contraction. I've finished the benchwork for a new 3-rail O gauge layout (12x20) and am about to start building scenery. My previous experience has lead me to ask - Has anyone ever mixed liquid latex into a mixture of plaster to make it more flexible and less frangible? Research on the internet hasn't answered this question.
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I've never done that but now I have so many questions! How has the floor patch held up over 30 years? And what kind of latex did you add to the concrete, and what percentage - by volume or by weight? You might want to experiment with the same latex mixed with plaster to see if it gives you the attributes you're looking for. It's an interesting idea for sure...I usually get broken plaster by doing something dumb and/or careless and the chipped or broken plaster is the outcome. I just shop vac up the mess and do some patching as needed.
Unfortunately, I did the latex mix so long ago that I don't remember, and I've moved several times since then so I don't know how well it held up. But I suspect it has done fine since it is/was out of sunlight and relatively protected by carpet/flooring. The thing that sticks in my mind that I got off the internet is that "latex and plaster don't stick to each other," but that was in the context of using latex as a mold for a plaster casting and not as an integral part of a plaster mixture. I think I will experiment and see what happens, and based on the results, either abandon use of latex with plaster or proceed to use it on creating my layout scenery base.
How to Mix Latex Paint with Concrete
- Pour dry concrete mix into a suitable container for the amount of mix to be made. ...
- Replace up to 20 percent of the water required with the latex paint of your choice. Mix the paint well before combining it with the concrete.
- Mix the concrete and paint thoroughly until there are no dry pockets or visible patches of paint. ...
- Apply the well-mixed concrete and latex paint mixture to your application and allow drying for the recommended time set on the concrete mixing directions.
I’ve mixed plaster and joint compound in roughly equal parts to increase plaster’s drying time, but have no idea if this mix would be more resistant to breakage than plaster.
A number of companies now make ready-mixed, flexible or elastomeric joint compound if that helps.
You will still need a base of plaster cloth for hills. There was a concoction invented by modeler Lou Sassi years ago called Ground Goop. Saw it in the Allen Keller video of Lou’s layout. Latex paint was an ingredient used. You could mix a large batch in a storage container and use it over time. Easily spread and dried slow. Scenery could be applied over or planted into it while still wet. Google Ground Goop and you can find the recipe for it as well as some substitute ingredients that will work.