Making O Scale Ballast

For O scale particle size should be about 1/16" - 1/32". That's 3" - 1.5" pieces. The sieve size is #8 (large) down to #16 (small).

Thanks. I checked this against a sieve particle size conversion chart and the Mesh Screen numbers don't line up. Am I looking at this incorrectly?

Don't assume that the geometrically correct size is necessarily the best choice--especially when dealing with very small features such as individual pieces of ballast. Very often, the best modelers deliberately exaggerate subtle features, less they be visually lost. The world of visual design is full of examples of this. For example, in typography the serifs (little nubs at the ends of lines) of small point sizes are relatively much larger than those on larger type. The idea is to make them visually similar, not geometrically similar. You need to use your eye, not your micrometer. 

P.S. -- Did you know that the bottom of the pediment on the Acropolis is actually slightly curved upward toward the center? It corrects for an optical illusion in which the intersecting columns makes it look curved!

Sorry, bad math on my part. I should have used a calculator to convert those fractions. Large sieve should be a #12, and small should be #20. Is that better?

I believe I recall that construction of the Acropolis with leaning walls was done to make it appear symmetrical and the sides seem straight because the Acropolis, being located atop a hill, is viewed from below. A rectangular (or square) object located above the viewer normally appears to have sides that lean in, and the altered shape corrected this so that the building, looking at it from below, appears to a viewer to have perfectly straight sides.  

A forced perspective thing. Of course, similar ideas are used in relatively sophisticated layouts in ways such as having HO trains running at the rear of the layout to give the illusion of depth, to make it seem like the HO train is in fact the same size as the O gauge one, but just further away.

How exactly are you crushing your rock to make O gauge ballast?

Interested,

Dale

Good point. The "Art" of model railroading isn't necessarily to achieve 100% scale accuracy; it's about doing what looks good. Look how much we have to fudge with curve radii, even with "scale" trains.

I welded an 8 inch piece of 3 inch diameter heavy duty pipe to a 1/2 inch piece of steel 5"x5". You can find these devices on ebay or from gold panning suppliers but if you have a welder they are easy to make. I put small pieces of dark pink and black granite rock I find along side the railroad tracks in the pipe and pound it with one of those 6 foot long dirt tampers you can find at the farm supply stores - it just fits down inside the pipe. I have been sifting the results of the first pass of pounding through three different kitchen sieves. One of the sieves results in particle sizes that range between .050 and .060 inch - this is right at the O Scale dimension. I use this on the track outside of the rails and keep it in place with a 60% water to 40% white glue mix. I use this mixture because it keeps the ballast in place but it is easy to break apart should a track or switch change or repair be necessary. I place the next larger size particles (maybe around .080") in between the rails but I don't glue it down and I keep the fill below the ties. I do it this way because it makes track design changes and repairs easy. The only downside is you can't vacuum the track. I use the larger size ballast in between the track because the chances of a grain getting up in an engine's gears is minimal. Eventually when I'm feeling more confident with the layout and track signal stability, I may vacuum it all up and replace it with a more prototypical ballast and glue it in place. 

I started off with a 2"x48" piece of rebar in a 3"x6" pipe after I hit Mr America status I purchased the Crazy Crusher. I didnt get this for my coal as that is already sized down. The was for my ballast and ore load needs. I found that real ballast is from my siding was wicked hard to crush so I went to a different type rock. My ballast is my - #14 mesh 0.051" and + #20 mesh 0.034" mesh. I purchased 12"x12" screens from McMaster Carr, cut and fitted into the top of joint compound buckets. I have attached some photos of classified sizes and my sieve system and crusher. This just works for me due to my volume. I can adjust my crusher so that it breaks down the rock to a size material that is close to the sieve size I am looking to process. 

Added to Scenery Sourcelist for reference.

Dave G.

Interesting----How does your ballast respond to a magnet?  Is it washed?  Is there friable dust in the mix?

Oh yeah I've seen the Crazy Crusher and wondered how well it worked. Will it crush 2 - 3 " pieces of granite? If I added all the time I spent pounding granite rock I probably could have afforded to buy one. I still have a lot of crushing to do so maybe I'll look into it.

I went to the McMaster Carr site and found the mesh page. I see they have multiple opening sizes for the same mesh number. Do I pick the opening size that matches what I want to sift to? Example: for the #12 mesh do I pick the 0.060" opening size? and for the #20 mesh do I pick the 0.032" opening size?

If you pick the #12 0.060" and the #20 0.032" the stuff that sits on top of the #20 will be perfect O scale ballast and gravel.

The Crazy Crusher works really well, you can adjust the throat at the bottom. As far as a 2" piece of rock yes, not sure about 3" it would fit just not sure about the crushing factor.  

I was just going to suggest the same: pass a magnet over it to pick up any loose metal shards....

50 pound bucket of roofing granules.  Available at roofing and siding supply houses.

Yesterday, I tried the roofing granules. They look nice from an overall color point of view and you can blend some cool colors but I can't use them for ballast because they are too light in weight. I don't glue my ballast in between the rails so I need the heavier weight you get from real granite so they stay in place. The roofing granules work well for ground cover, old roads and trails as long as you cement them down.

Some people say kitty litter works well for ballast and they often get razzed about it. I haven't tried it. Actually I don't do any ballasting on my mostly "temporary" 3-rail layouts because I like the freedom to change things more easily.

Kitty litter ballast is one of those things going way back (like decades ago).  Two issues arose: 1) clay dust settles on everything and 2) cats can't help themselves.

Fred

I can't speak to the cat problem--not my religion. But as for dust, you definitely should sift the KL before using.  I use an old kitchen colander.