Run a magnet through it

The dollar store is a good source

... for kitchen strainers that haven't seen the kitchen.

Those (Kitchen strainers)  are  (in our house) food grade... and remain so after ballast is cleaned.  The 2 sets NEVER meet!

You can double-up a cheap strainer for a finer mesh.  

A suggestion

Hi Nick,

I'd recommend following Joe's advice above. I'd like to make an additional suggestion before you apply the magnet. - Put your magnet inside a zip-lock sandwich bag or similar. It makes getting the magnetic stuff away from the magnet so much easier. 

Metal Kitchen strainers...

Know w3hat happens when you attach a magnet to it, and then strain the sand?

Sure, you should still run a magnet through it after you strain, but you'll find only a fraction made their way through.

(I have a beach close by for my ballast... though, I usually mix it with a bit of red rock)

Magnets

Never did a magnet check but a small rare earth magnet in the sieve or shook up in the ballast cut sounds like a good idea!

Nick

@John Garaty, I'm guessing

@John Garaty,

I'm guessing that the fine magnetic dust can somehow get into the can motor of a loco?

@ Deem

Hi Deem and all

There may be more than one problem than just simple ingestion into locomotive motors.

The presence of magnetic particles particles suggest the presence of iron, nickel or something similar. It is probably an iron oxide of some type present in the parent rock. The local sandstone here is about 15% iron. Crushed basalt fines would be worse magnetically than crushed granite fines because of the higher iron content in the parent rock 

First problem - if the dust is fine enough and gets disturbed enough to cause it to get free in the air, then it will get attracted to anything steel (like slightly magnetised trip pins) or magnetic nearby (like the magnets in motors). The motor is usually further way but the magnetic fields around it are usually far stronger than for a magnetised trip pin. Motor revs are usually pretty high so the spinning armature might just cause enough air turbulence inside the body around the motor to cause this magnetic dust to be sucked into the motor. Problems won't occur immediately, but over time the dust could build up around the magnets. It would look something like carbon build-up that occurs around the commutator area in an old heavily-used DC motor. 

Second problem is a "compound if". First "if"- This stuff, if magnetic, may also be slightly conductive. Second "if" - If you get enough of it picked up with lube oil etc and deposited as a layer of "crud", (third "if') then you might be able to track a current across something that should remain electrically isolated on a locomotive. This is unlikely but it would be very hard to diagnose.

Because we are running small coal skips with powerful magnets close to the ballast, magnetic particles in the ballast are probably far more of a problem for me that for almost all other model railroads. The following photo shows some of the pickup on the black circular magnet for just one of the skips. This pickup occurred after the ballast had been glued down and occurred after several trains of skips had been run over the ballast. All skips in the train exhibited some pick-up, and some were far worse than this skip. For scaling purposes, the brass axles are 1.5 mm (0.060") diameter. 

  This magnetic pick-up here is really pretty fine in size and could be quite mobile.   

I realise that there are a whole lot of "mights" here. But if you can avoid getting magnetic particles into your ballast in the first place, then this is probably a "good thing".

Thank you, John for that

Thank you, John for that thorough explanation.

I can see how fine dust, when applying scenery in the messy stages could get into everywhere, which I have done in the past, but was luck my locos were put away or covered.

As for ballast, I think I have used some unchecked dirt in the past, but it was soaked with matte medium and sealed with other weathering mediums hence maybe my luck with no contaminated locos.

On my current layout, I have a stretch of about ten inches of ballast on the track to my TT that has some magnetic material in it, but it seems to be sealed well. I ran a powerful magnet over it to see if any dust would cling to it and there was none, but to be safe I might seal it again.

Pile at the back of the layout

We often find some of the small scale modelers sifting through our 1/4 to 1/2 ton pile of ballast. Not that they are going to use much, but they tend to spread out the pile. Not fun to try to scrape the stone out of the grass.

work for?

Will your trick of strainers work for loose clay/sugarsand mix I have in FL? Might have to test it out when I'm off from work. We still just snowbirds hovering around in the retirement community where I'm a cook at.

@ sn756krl

Might not hurt to rinse them in water and then dry them first.  This step will remove a significant amount of salts (and clay super-fines) that might effect adhesion of the adhesive mix.  The rest should do just fine.

Give it a try!

The sieving sure seems like a

The sieving sure seems like a lot of work when you can just buy a good sized bottle of real rock ballast from Scenic Express for a modest price and it will cover a lot of track.  But there are hobby's within hobbies and rolling your own ballast can be one of them of  course.

Making my own ballast

Iron ore ballast

The iron ore stockpile spurs on my layout have real iron ore (hematite, FE2O3) between and along side the rails. While there is a very small amount of magnetite (FE3O4) mixed in with it, I've never had a problem with loco performance. I glue it down well with dilute matte Mod Podge, and check it with a magnet afterwards. Nothing picks up on the magnet. I use the real thing because nothing else matches the color, sheen, and texture.

The ores from the mines I model were all hematite. Magnetite ore is still mined today from the Tilden Mine near Marquette, MI.

Sieves for soil analysis

A set of sieves used for soil analysis aren't all that pricey since the rings are now made of plastic rather than brass.  The advent of home schooling has resulted in a lot of scientific equipment being available at lower prices. I purchased a set for less than $40 on the Internet.  Also I just noticed that various sized stainless steel mesh is available as well so you could make your own sieves.  Sieves in the 100-200 mesh range would likely be the most useful for ballast. A dry brush can be used for moving material through a fine mesh.

It's my opinion that Woodland Scenics ballast is far too coarse even in their fine samples for HO.  Colored sand is available at Michael's and Hobby Lobby.

Robert

Mesh size

Mesh size is the number of screen openings per inch. Allowing for wire diameter:

200 Mesh = ..0029"/ opening x 87 (HO) = .25 scale inches

100 Mesh = ..0059"/ opening x 87 (HO) = .51 scale inches

20 Mesh = .0331"/ opening x 87 (HO) = 2.88 scale inches. Close to the size of actual ballast.

30 Mesh = .0234"/ opening x 87 (HO) = 2.04 scale inches. Close to the size of actual ballast.

Hi Hans and Robert,

Thanks for that information.  I had to use sieves in the chem lab on occasions and never made the size of the particles or openings discovery.  When I wanted to buy a set of sieves, I balked at the price of even a couple of brass sieves!  Now that the job is almost finished I'll stick with the kitchen strainers.

Really good information for the people who want to go this route.

Thanks again.

Nick

The only time I ever used

The only time I ever used sieves was when I worked as a geologist (my education back ground) for a consulting firm if a client required it.  Most of the time I classified soil sample visually in to cobbles, gravel, sand, silt and clay.  I never though about using them for train track ballast but back in that day, I didn't have any space for a layout.  

TMTV A Better Way to Ballast Turnouts

Despite all my trackwork being complete I picked up some good tips from Joe Fugate in the latest TMTV “The Back Shop”.  Joe’s method for preventing the points from getting glued works well. I used a different approach.  I apply all the ballast on the turnout.  I then put a drop of Labelle 107 plastic compatible oil on each tie that is under the moving points.  I move the point back a forth a few times to get the oil underneath them.  I also put a few drops between the throw bar and the two head ties and on the pivot point.  I then soak all the ballast with dollar store 50% rubbing alcohol.  I then apply diluted white glue with an eye dropper over all the ballast. If a drop of glue gets on the tie where there is oil it does not stick. Even so, after a few hours I come back and move the points a couple of times just to be sure nothing gets stuck.  After the glue has dried there is very light film of oil under the points which does no harm. Any oil on the ties between the points I wipe off with a Q-tip.  After using this method on 72 turnouts over 20 years I have never had one get even lightly stuck with the glue.

Applying the Labelle 107 oil.

Oil under the points, on the throw bar and the pivot point..

Applying the diluted white glue.

Finished turnout

Questions about the Teknabond wall adhesive to fix ballast

Joe, your suggested use of Teknabond wall adhesive to bond the ballast was new to me and I went through that part of the TMTV video to pay closer attention.  Had you actually mixed that into ballast you used for your demonstration?  Do you have a recommendation for a ratio of paste to ballast?  Should the two be combined just before application, e.g. to prevent possible moisture absorption if premixed and stored?

Wall adhesive

Someone suggested it to me and Barry Silverthorn wants to try it, so he got some. Since he had some on hand, I thought I’d mention it. The idea is to crust the ballast with a wet water spray and leave it to set up. Then come back in later once it’s dry and give it an application of diluted white glue to finish up.

Since wet water and white glue do the job completely too, that’s what I used on plain dry ballast. So no, I did not mix the wall paste in with the ballast in my demo. I showed you how I ballast, which is first with the white glue straight around the points, then ballast the rest of the turnout as normal by spreading the ballast dry, soaking it with wet water, and then dribbling on white glue.

The cool thing about my technique I showed on TMTV is I don’t ever get points that stick and I also dont need to flood the points area with oil, graphite, or any other special preparation. Just do it like I show and the points never stick.

Homebrew Ballast

A little testing...

In all fairness to people who are following this post, I did some experimentation today. I took a Neodymium magnet the size of the showing part of a pencil eraser and put it in a one quarter cup of my sieved and ready for HO scale ballast. I found that there were fines that would pass a 200 mesh sieve and some of the ballast stuck to the magnet. Not a big surprise.

Next I wanted to know if the homemade ballast was going to be an issue after it was glued down around the ties in the roadbed. Initially I took the cleaned magnet and placed it on a nail and passed about rail height above the center of a 10 foot section of track once and right in the middle of the rails. I found some fines stuck to the magnet.

I wondered where the magnetic fines came from. I also wanted to remove any mobile magnetic particles that were present on or near the roadbed. To test and help remedy the situation I took a Centerline track cleaning car and placed two magnets on it. Since the car was non-magnetic, I had to place a magnet on the top and the bottom of the car to hold each pair of magnets in place. The magnets would only sit in the center of the car so as not to interfere with the movement of the trucks. I also took a gondola car which happened to have a steel weight in it and placed two magnets on the bottom of the car on the outside edge to clean near and beyond the rails. The next picture will show the two cars with the magnets in place.

I have a section of track that is newer and not ballasted that is about 110 feet long and been used for about five years. The ballasted section is about 80 feet long and been used for closer to 15 years. I sent the two cars around the new section once and this is a picture of the results.

I sent the same two cars with cleaned magnets around the ballasted section once and this is a picture of the results.

The results indicate to me that mobile magnetic particles are more omnipresent than I ever suspected. The origin of the particles is not confirmed. There were a few particles of homemade ballast on the magnets after passing the ballasted section. I cannot confirm that the ballast was torn out of the roadbed or just an uncleaned artifact. I have checked the fuel tanks of my diesel locomotives for ballast and fines and found none. The frames of my diesel locomotives are non-magnetic and the electric motors sit right over the fuel tanks. The magnetic field of the Neodymium magnets I used to scavenge any stray magnetic particles is much stronger than the magnetic field created by the magnets in the locomotives particularly with respect to distance from the roadbed.

In conclusion, I believe that using homemade ballast that contains magnetic particles is a valid procedure. Magnetic particles may be removed before use with a magnet if one feels it necessary. They may be ignored if the number is not significant enough to cause a short circuit between the two rails. A short circuit possibility can be tested with an Ohm meter. If a short circuit is a possibility, a layer of glue forming an electrically insulating layer could be applied and allowed to dry prior to the actual ballasting process. Otherwise the ballast may be positioned, glued and allowed to dry. Vacuum cleaning and passing a magnet over the ballasted area to capture any stray magnetic bits would finish the procedure

.
Here’s a table of the resistances I found in my ballast and about the layout.

Air> 40M ohms
Plywood> 40M ohms
Glued ballast about ¼” distance between probes> 40M ohms
Ballast, dry, just sieved again about a 1/4"> 40M ohms
Nickel Silver track                                                         0.3 ohms in about 1.5 inches
Me by grabbing a probe in each hand                         about 1.5M ohms
10K ohm resistor                                                         9980 ohms

Nick

P. S. I wrote this yesterday and found the latest response pointing to Bill Brillinger’s thoughts on making and using real rocks. I think that this and his post should go a long way to making real rocks work for you if you so desire.  Hope this helps!!!

@JoeF

Joe where can I find that squirt bottle/atomizer you used in the show?