This past week I returned to the location where I previously discovered the mineral magnetite (iron oxide FeFe2O4) at Cape Blomidon, Nova Scotia, Canada. Last year I set a GPS waypoint there so it was easy to find. The purpose of this field trip was to collect more magnetite for my HO scale Cheverie Mountain Railroad layout. Located on the Bay of Fundy with the highest recorded tides in the world, this cape is one of the most beautiful geological sites in my province.
It is a long hike to the magnetite location so it is important to leave the main parking area as the tide is going out. Otherwise, you may end up trapped by the tides when the water reaches the base of the cliffs. The metallic magnetite looks like this sample in my hand:
As a physicist I have more than 30 years experience working with magnetic materials that dates back to the beginning of my Masters Thesis in 1983. I am bringing this experience to my layout in the forms of iron ore and a host of magnetic sensors for animation, all made from magnetite found near my real layout area in Nova Scotia. This weekend I will illustrate what I can do in this thread.
Dennis
Welcome to the forum. I appreciate your non-traditional approach to your modeling and will be following your efforts. I am enjoying your posts and I hope that you will keep them coming.
Joe
Here are some of the samples of magnetite that I collected in the field yesterday (21 April 2017). Some are massive chunks of solid magnetite and others are coatings on other types of rock and minerals.
The name magnetite is a bit misleading. This mineral is not a magnet that other metals are attracted to, rather, it is an iron rich mineral that is strongly attracted to magnets. This beautiful sample looks like someone painted the magnetite on a piece of quartz. This relatively heavy magnet is firmly attached to the magnetite.
Magnetite in sufficient quantities is a source of iron ore in some locations around the world, but not here in my layout area of interest in Nova Scotia. However, to HO-scale people this is a major source of iron ore so it will be featured in my layout as such. Let's work with this massive magnetite sample shall we?
All processing of my magnetite specimens takes place outside so that the layout area does not become contaminated with iron particles and dust. Magnetite is also electrically conductive, I'll exploit this property as well, so you don't want to short out all your electronics or even breathe in the dust.
With a metal hammer sparks may fly so don't crush magnetite near propane or gasoline tanks. Also, don't use your spouse's favourite doilies, try disposable J-cloths. A magnet will pick up the small pieces.
I use a variety of sieves to separate particle sizes according to my anticipated applications. If I can't find a sieve with the hole size I need, I make one by punching lots of holes in a tin/aluminum can.
So, back in the lab, that massive piece of magnetite has been crushed and sorted. I filled a hopper with real iron ore from Nova Scotia (I can change the scale and use smaller pieces at a later date). Some of the larger pieces will be used in scenery or embedded as part of a magnetic sensor system. Smaller pieces like those in the jar will be used in the fabrication of HO scale items that can be set into motion under the influence of a magnetic field. The powder/fine particles in the beaker on the scale can be used in building materials. I will be demonstrating some of these ideas as the weekend progresses.
Another component of magnetic sensor systems that I will design for this layout is the ceramic magnet. These 18-mm-diameter magnets won't rust and can be glued to many other materials. I buy packs of 100 discs on Amazon.
Indeed, these magnets are quite strong for their size ...
... and they crush to pieces easily! By now you may be inclined to think that scientists like to break stuff - you would be right. The pieces are now better suited to HO scale applications.
Two other important sensor components that I have used in the past are (1) electrically-conductive copper decals and (2) spring-loaded micro-electronic contacts. HO scale train wheels show you how small these contacts are, and they have springs inside!
Hi, OldSchool
OldSchoolScratchbuilderMagnetite is also electrically conductive, I'll exploit this property as well, so you don't want to short out all your electronics or even breathe in the dust.
I'm sure you have considered this but just to mention so that others who may want to use landscape or ballast materials on their layouts that anything electrically conductive is liable to wreak havoc at the rails and switch points or especially motors and speakers that have magnets.
I came across some cinder ballast material, commercially made, but it still had a large percentage of ferrous material in it. If it had been used as ballast it surely would have acted just like a BIG resistor across the rails.
So, I caution anyone against using conductive/metallic materials around their electronics.
I occasionally run this magnetic pick-up car and I'm amazed what it finds in the track-bed.
Some locomotives have low-mounted speakers (in the fuel tanks) and you surely wouldn't want this stuff in your speakers!
Thanks for the informative thread!
Regards, Ed
Excellent advice! In my case, all ferrous/ferric materials will be sealed, including the ore in the hopper cars. Also note the multimeter in my pics. Everything is tested for electrical conductivity. BTW that magnetic pick-up car is a great idea!
OldSchoolScratchbuilder Excellent advice! In my case, all ferrous/ferric materials will be sealed, including the ore in the hopper cars. Also note the multimeter in my pics. Everything is tested for electrical conductivity. BTW that magnetic pick-up car is a great idea!
I certainly noticed that classic vintage Leader meter you have there I have a few vintage meters as well as some more modern ones. Can be a whole separate hobby, collecting and restoring vintage test equipment. So far I have mostly resisted.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
OldSchoolScratchbuilderBTW that magnetic pick-up car is a great idea!
I'm pretty sure it was an idea from RR_Mel (Melvin Perry) but using the MR forum search I can not find the original thread!
Thanks, Ed
rrinker I certainly noticed that classic vintage Leader meter you have there I have a few vintage meters as well as some more modern ones.
I certainly noticed that classic vintage Leader meter you have there I have a few vintage meters as well as some more modern ones.
Well that tells my age LOL. I bought it brand new in the late 1970s I believe. Still in great condition and works as well as when I bought it.
gmpullman I'm pretty sure it was an idea from RR_Mel (Melvin Perry) but using the MR forum search I can not find the original thread!
There are many articles on track cleaning in my model railroad magazine library that dates back to the 1950s. I'll have a look there and post my findings.
By mixing fast-drying wood glue with shale particles and magnetite powder, Rusty Steele and Sons, Ltd. (the name of my HO scale metal scrapyard) makes large blocks for building foundations and retaining walls. This type of block, one of several Steele products, is attracted to magnets because of the embedded magnetite. This morning I glued a small piece of ceramic magnet that I broke yesterday to the feet of an HO scale seagull. The seagull-on-ceramic-magnet (that looks like a rock) can now be moved anywhere in the layout where there is metal.
Seagull standing on his favourite rock. I can move the gull anywhere there is embedded magnetite and he won't easily fall down.
In order to incorporate magnetite as a sensor component, its electrical properties need to be understood. In this photo you can see that a continuous electrical path exists between the ohmmeter probes giving a near-zero electrical resistance. In other words, as already mentioned, the magnetite is an excellent electrical conductor.
When two magnetite layers are separated by a dielectric (the hard brown stone in the middle may be the mineral jasper) the sample may exhibit electrical capacitance.
Indeed this sample has a capacitance of 0.015 nF (nanoFarads). It may be necessary to take this type of capacitance into account in some circuit designs.
Designing sensors that actually do neat things will take some design and testing work so I'll wrap up this thread with a few pictures showing you how Rusty Steele and Sons Ltd. embed pieces of magnetite in their block products. This is one in progress that they started last night. First they dip into their stock of processed red and grey sandstones, shale, coal, and gypsum - all gathered from field trips in and around my real layout area on/near the Bay of Fundy.
In this case the company is making a concrete block out of Windsor gypsum particles. Three grams are measured.