Sunday, December 20, 2015

WTF doesn't even begin to cover it!

I've been playing around with various options for yard ballast.
The "cinders" I've been using isn't quite doing it for me.
I did a little online searching and came across the use of "sanded grout" as a ground cover. I liked the visual results I saw in the photos. So I bought a box and started playing with it.
I found that just bonding it down with water and relying on the integral bonding agents to be inadequate. Thin Weldbond left a shiny surface which was not acceptable.
So I bought a jar of Acrylic Matt Medium. Thinned it about 3-1 and this is the result.
What is all this white crap?!?!?!?
I'm not sure where to go next with this. Can I even cover this or do I have to rip this section of track up and start again?
I've never heard of this happening with Matt Medium. WTF?


Tim Warris said...

I've had that happen to me, but it was when I was using alcohol as a wetting agent for carpenters glue. I believe I just painted over it.

Ted DiIorio said...

I'm using wet water (a few drops of dish detergent in water) sprayed on then white glue cut down 50/50 with water applied with a dropper. I'm using black sanded grout from Home Depot for cinder ballast.

chris mears said...


I was sorry to see and read the grout wasn't working out for you. I have done some work with grout as ballast and here's what I learned:

I used Polyblend sanded grout that I purchased from Home Depot here in Prince Edward Island. It wasn't terribly expensive and I quickly found myself with more than a lifetime's supply. When I first spread it out I figured I'd bond it using my traditional means of thin white glue, etc. as we all do for "regular" ballast work. This was a failure twice: I found I couldn't get the glue thin enough to draw into the grout so all my work to level out the profile of the grout was a waste. In the name of science I pushed ahead and soaked the lot in glue. Similar to your result, all I got at the end was a nice layer of ballast entombed in a puddle of dry glue. I didn't try matte medium but wonder if that might work just as well as my - in my opinion - failed experience with the white glue method.

After some time, some wine, I tried again on a new length of track. This time, I just misted on plain tap water with no bonding agent (glue, etc) - after all, that's how the grout would be used normally anyway. Early experiments proved that this alone seemed to work to hold things in place. If I did work at it I could loosen it up but it wasn't fragile enough that I worried it would work its way loose and wind up in a mechanism.

What I'm curious to try is varying the depths. When I first used it I wanted it for a 1/48 scale line to represent dirt ballast. With the thicker ties, I could lay in a deep layer of grout. Were I working in a thinner layer it might be too fragile? I don't know and this is just a thought.


Anonymous said...

I had this happen when I used Scenic Express products and matte medium. I scraped it off after it dried and tried again with glue. Got the same results, but I was able to make it work when I applied lots of wet water. In the end I went back to using real rock ballast from Highball and my own home sifted limestone, and I've had nothing weird happen since.

Anonymous said...

Hi Pierre;

How hard is your potable water?



Pierre Oliver said...

Not very, as far as I know.

Shop Foreman said...

Some Matte Medium seems to have a slight bit of silica in it which will also leave these deposits, I generally let my diluted mix sit for a day or I filter it into a new bottle as I need it.

Ryan Mendell said...


I use the Home Depot Polyblend sanded grout mainly for gravel/dirt roads. The only way I can get it down without the effect you are seeing is to use 90% alcohol wetting agent and good old white glue thinned 50% with water. Then spray the whole thing with more 90% alcohol with a mister immediately. This is one of those times when more alcohol is the answer to the problem.


Anonymous said...

On the bright side, if you want to model a stretch of track that has bad drainage and is pumping mud, you now know how to achieve the look!


Randy said...

I've been struggling with the glue drying white on my layout too, and I'm using grout too, along with some other materials. Even when I duplicate the exact process that I used on another layout without problem. So I'm guessing it had to do with my basement environment too.

Regardless, the process I've been using is to do at least two layers, partially because the first layer gives some teeth to ensure the second layer stays where I want it, and also to avoid saturating with too much fluid.

I use straight Future with a pipette to wet between the ties, and along the outside of the track, and from there wet the edge of the wet area and let capillary action expand the wet spot.

For areas where I can see the white coming to the top I sprinkle on additonal ground cover to help soak up the Future.

I have also tried various application using wet water, alcohol, white glue, Mod Podge, matte medium and others. The Future doesn't require pre-wetting and works well, and doesn't dry glossy as you might expect.