DIY Alpine Stone Trough Prototype Build - August 2026

Just a few days ago, I posted some inspiration and details of a DIY Alpine trough project that I found on Instagram where someone used a *real* stone trough as a water feature (wasserspiel).  I talked about buying a styrofoam cooler to use as the chassis and building out the 'stone look' with concrete.  

As luck would have it, I came across a free (to me) styrofoam cooler this past week.  It is small.  At least....smaller than I want for a wasserspiel or...ahem.... Alpine stone trough.  

But, for a prototype?  I think it will work perfectly.  

The outside dimensions of the prototype are 15" long x 11" wide x 9" deep.   It has 1" thick walls.  

Based on what I picked up from watching various YouTube shorts, Instagram reels and reddit posts, there are a number of ways to go about DIY'ing your own stone trough.  You can apply burlap and concrete.  You can apply something like an acrylic fortifier to try to get the concrete to adhere to the styrofoam cooler.  Or, some people have had success with Vinyl Concrete Patcher.  Photo below.  It is sold in a ten pound pail at the orange Big Box store.  You mix it as you need it and spread it out as you see fit. $12.00 for a bucket and I ended up using more than one and a couple of pounds of the second bucket. 

This is the first time I've worked with this concrete patcher, so I started in batches.  I mixed up a couple of pounds and applied it to one side of the cooler.  We're dealing with a number of vertical surfaces and I wasn't sure how this stuff would adhere (and/or slide-off), so I just did a little bit at a time.  That, well...created seams from where I stopped one day and picked up the next day.  I did my best to hand-blend them in, but it certainly isn't perfect.  

And, perfection isn't what I'm after with this prototype.  I'm after proof-of-concept.  Will a foam cooler, covered in some stone-looking product, hold water, withstand some level of weather and act as a water feature?  

After applying the patcher to all the sides, I ended up with a center well that is 7" wide x 11" x 7" deep.  Here below are a few photos of how it came together.  I used some of the little tricks I've used on clay pots like rubbing them with freshly-cut grass and using some wet wood chips to try to age them.  

I opted to cut a small notch in one corner to serve as the spout to allow the water to run-out.  I'm not sure if this is big enough and/or at the right height.  But, that's what prototyping is for, right?

I also took some brown and cream paint and watered them down to make a wash.  This changed the stone from grey to more of an earth-tone.

One of the things that I didn't do on this one is to use limewash.  I've done that for clay pots before.  See this YouTube short for how this creator used limewash.  

Once we know if this thing is going to work, there will likely be a "next time".  That might be over the Winter when I have more time.  Or, even next Spring.  But....if there is a Next time: use a limewash.

I'm not sure if it matters at all, but each time I applied a coat of vinyl concrete patcher, I wrapped the whole thing in a plastic garbage bag to try to contain some of the moisture and (hopefully?) slow down the drying/curing process to get it to be as strong as possible.  After waiting a few weeks of curing time, I grabbed a can of Gorilla Waterproofing Spray and laid on a few coats. 

Now....we find out if it holds water.