MAGracing Forum

Markus, thank you for sharing your ideas and experience. I'm glad to hear that you have developed a track with cars that have “nearly...perfect conditions”. I assume by “nearly...perfect conditions” you mean that the cars don't loose the wire unless they are driven too fast around corners, cars can navigate turns at realistic or higher scale speeds, cars don't experience front-end shimmy (front wheels dancing) at high speeds, cars have realistic acceleration and traction, and cars can change lanes reliably at medium to high speeds. (There is no need to change lanes at slow speeds in my opinion.) You should be proud of your accomplishment. It's not easy to get great performance from the system and it takes a lot of persistence and work. Congratulations! (Good performance on the other hand is quite easy to achieve with a little guidance from Wes and other members of this forum.)

I believe that my cars and track provide excellent performance with the exception of front-end shimmy at speeds over 165 mph and as a consequences, inconsistent lane changing at those speeds. Top speed is about 200 mph. My cars are unmodified as received from Wes, with the exception that they have .06 mm (.002”) thick tires added, which are made from disposable black nitrile rubber gloves. My track is made per Wes's standard, except that my piano wire is .032” diameter instead of .028”. I have tried your idea of lowering the side magnets, which are located in the chassis between the front wheels, and which repel the steering guide magnet, and thereby help to keep the front wheels pointing straight ahead. This has not helped much. I'll continue to experiment.

I know from Wes and my own experience, that reducing the clearance between the bottom of the guide magnet and the top of the wire helps reduce front-end shimmy. The minimum clearance that one may achieve with good results is primarily dependent upon the maximum thickness of the paint covering the wire and the consistency of the vertical distance from the top of the paint covering the wire to the top of the track surface where the tires actually make contact with the painted track surface. In the case of a track made with slots for the wire, a variation of +/- .003” from flush causes problems. Depressions in the track surface where the tires make contact with the track, which may occur in the case of a baseboard made from foam insulation board, makes matters worse. I suppose that in the case of a perfect track with slots for the wire, one where the top of the wire is perfectly flush with a smooth, flat, and hard baseboard material prior to the last coat of paint and where the last coat of paint or other material covering the track and wire is a uniform 2 mils (.002”) thick, one might be able to operate cars with a static clearance of .004” between the bottom of the guide magnet and the top of the wire, 0.002” for paint and 0.002” for an air space between the magnet and the paint. I think that would be a perfect track for these cars, but which a hobbyist cannot achieve in my opinion. (A typical sheet of computer paper is .0035 to .0040” thick. The radius of my front tires varies by more than 0.001” which necessitates more than 0.001” of air space under the guide magnet.) As I stated yesterday in my post, “I have concluded that the bottom of the guide magnet of my cars is usually running about .005 to 0.010” above the top of the wire, and .002” to .006” above the coating/paint that is covering the wire. That may not be perfect but it's good enough to achieve very good racing performance from my cars and have a blast!

As Wes has told us, and as you have discovered, when we change one thing in the system of track and cars, we often have to change something else, because many inter-related factors affect performance. I still have about 65 feet of track to build and I'm sure that many others will be building tracks in the future. If you, as well as other members, answered the following related questions by posting a reply, the most relevant information for building a track, would be easy for everyone to find. I as well as others, would be very grateful. I have numbered the questions so it will be easy for everyone to number their answers correspondingly.
1. Did you build a track which will always be protected from the weather, such as an indoor track, or did you make an outdoor track, not protected from the weather? If unprotected outside, is it on the ground or on supports of some kind?
2. Is your track permanently located in one place?
3. What did you use as your baseboard material? How thick is it?
4. Did you use steel piano/music wire or thin steel strip/tape? If wire, what diameter and how long are the pieces? If steel strip/tape, how thick and how wide? (Piano wire is also called spring tempered wire, and spring-back wire in some places.)
5. Does the wire or strip/tape have any rust inhibiting coating? If so, what is it and is it effective? (A lot of piano wire is phosphate coated to inhibit corrosion.)
6. Did you glue the wire or strip/tape in a groove/slot in the baseboard or on top of the baseboard?
7. If you cut a slot, what method (or type of tool) did you use and how difficult was it to maintain the correct depth??
8. If you glued the wire on top, what did you use as fill material around the wires to cause the top of the wire to be flush with the track surface where the tires ride?
9. What glue did you use to adhere the wire or strip/tape to the baseboard?
10. Did you put any undercoating (paint) on the baseboard before you attached any wire or strip/tape to the baseboard?
11. Did you apply any paint or other material over the baseboard and wire or strip/tape, after it was attached to the baseboard? Is so, what type of paint/coating? Flat? Glossy? Water based? Oil based? How did you apply it? About how thick is the coating over the wire or strip/tape?
12. What is the shortest radius turn in your track? About how fast can your cars go around that turn. Is that turn banked? If so, about how many degrees? Is it a hairpin turn?
13. Do you have any hills? If so, what is the grade/slope of the steepest? As an example, 1 unit of rise over 10 units of run = 10%. Canton Street in Pittsbugh, PA has a grade of 37%, one of the steepest streets in the world. Can your cars start and stop on your steepest hill?
14. Is your track made of sections which can be put together for racing and taken apart for storage? If so, how do you fasten the sections of track together, and are they placed on a table or similar structure or on a floor or similar relatively smooth surface?
15. Do all of your lane change points in the track incorporate a steel lane change plate, about 0.009” thick x 0.185” wide, such as the type sold by Wes? If not, have you found anything that works better?
16. Have you done anything unusual in building the track, something unique...perhaps something you invented yourself, to create a feature or to deal with specific problems in a part of the track or handle cars that loose the wire? Are you satisfied with the results?
17. Did you modify or change the wheels and/or tires that came with the chassis that was sold by Wes prior to January 2015? If so, what exactly did you do and what effect did it have?
18. Did you make any modifications to the standard chassis, that was sold by Wes prior to January 2015? If so, what exactly did you do and how did it affect the performance of the car?
19. If you were to build another track, what might you do differently?
20. Please add any other question and answer you think might be helpful for other members building tracks.

I will answer all of these questions for my track in my next post. I hope you will also.

puuh, thats a lot of questions, but i will do my best to answer it. will take some fotos and make a clear report. i wanted to make a video but my handy is old, and the quality of my camera is bad, looking for something better by e-bay. as soon the weather will gets better i will start my outdoortrack, sun is shining but very cold outside.

so it began. the underconstruction is fixed in my basement, it were my old traintable. standing tere for 25 years, never finished, because it was not enough room for all my parts i have. i killed it and screwed a new plate above to have it clean.groundplate were 2,5cm stabilisised with cheap constructionwood. the new is 1,0cm. i wont remove the old grass thats the reason for new. space is 4,00x3,20m.

Here are the answers to the questions posted March 1, 2015 as they pertain to my track.
1. My track is outside unprotected from the weather, on the ground.
2. My track is permanently located in one place.
3. My baseboard is 1” thick extruded polystyrene (XPS) rigid foam insulation board. (Two inch thick XPS is available that is more resistant to compression. It is often used under concrete floors and around foundations of buildings.)
4. I used 36” long pieces of .032” diameter steel piano wire.
5. Yes, my wire is phosphate coated to resist corrosion. It is effective in preventing corrosion due to tap water and rain water, except on the ends or where the coating is scraped or sanded off. It is NOT effective in preventing rust when the wire is glued in place with PVA glue, even water proof PVA glue. This kind of glue is often called carpenter's glue, wood working glue, and white glue when it is white. These glues are acidic.
6. I glued the wire into a slot.
7. I used a Dremel rotary tool with a router attachment and a .035” diameter fish-tail carbide router bit. It was difficult to maintain the correct depth. Other than that, it was easy to cut the slot in the foam baseboard. I did not break any bits in the foam. I broke a lot of bits trying to cut a slot this way in MDF.
8. Not applicable.
9. I used ACE Hi Tech Adhesive/Sealant. It's claimed to be better than silicone in adhesion, elasticity and paintability. In the future I would use Lexel Adhesive/Sealant by Sashco, Inc. It is similar to the ACE product.
10. Yes, I applied one thin coat of white elastomeric roof coating to the baseboard with a foam roller before I cut any slots in the board.
11. Yes, I applied 2 thin coats of elastomeric roof coating over the baseboard and wire with a foam roller. After that I applied a thin coat of flat gray 100% acrylic water-based exterior house paint suitable for hot desert climates. The total thickness of the 3 coats over the wire is about .003” to .005”.
12. The shortest radius of any turn is 9” or 24' to scale. It is not a hairpin turn (180 degrees). It is a little over a 90 degree turn. It is banked 8 degrees and my cars can navigate that turn at 100 mph. That's about ½ of top speed.
13. Yes, my steepest hill has a grade of 8.5%. It is a long hill and my cars can start and stop on it. I doubt that my cars could stop going down a hill with a grade in excess of 10%.
14. No, my track cannot be taken apart for storage.
15. No, all of my lane change points do not incorporate a steel lane change plate like those sold by Wes. But, I have not found anything that works better than those plates.
16. Yes, I have made provisions to attach portable model concrete barriers in a few locations to force all cars to turn instead of relying on everyone's ability to turn at an intersection. There is more about this in a previous post in this thread. I might try installing “catcher” wires in a few spots to help cars recover when they loose the wire.
17. Yes I added tires made from rings cut from fingers of disposable black nitrile rubber gloves to the stock wheels. This greatly improved traction and thus acceleration and cornering speed.
18. No, I have not modified the chassis.
19. I would reduce the length of straight track prior to a lane change point from 36” to 18” to increase the distance and time to pass another car. I might experiment with fiber glass panels and resin for the baseboard and use resin to encapsulate piano wire in a slot. This might be easier than my current method and provide better results. Might also try using .1 mm or .2 mm thick x 4-5 mm wide nickel plated steel strip/tape instead of music wire, for the same reasons noted above. Also, I would expect the nickel plated steel to be more rust resistant than the phosphate coated piano wire I've been using.

I hope more members will answer these questions in a similar manner, so that many relevant questions and answers regarding track building, can be found quickly.

I have decided not to use fiberglass reinforced plastic (FRP) panels. They are very flexible yet gravity will not hold them down flat. They curl up at the edges and must be attached to some baseboard with adhesive. Also it is extremely hard to cut a slot in them, for my .032” piano wire, using a .035” diameter router bit.

The remainder of my track will be made so that I can step on it carefully without damaging it. That will require a different method of joining sections together. During the next couple of weeks I plan to experiment with a couple of techniques.

If I were to build a new track, I'd still be interested in trying .2mm x 4 mm nickel plated steel strip instead of piano wire. (The diameter of the guide magnet in the car is 4 mm.) I would expect the steel strip to greatly reduce construction time by eliminating need to cut slot for the wire, and it might reduce front-end shimmy. However, I won't use .2mm steel strip for the remainder of my track, even if I could find a source for it, because it would be extremely difficult to make both the old and the new portions of track compatible, with respect to the magnetic attraction between the car's magnet and the track's wire/strip.

For those of you interested in seeing a video of my track, you can view one at
viewtopic.php?f=3&t=515

In my original post on this topic I stated:
"I glue sections of track together using [1" thick] 8"-12" wide pieces of insulation board placed under the seam/joint. Then I seal those joints with caulking compound or elastomeric roof coating and paint. Many types of adhesives will work for connecting sections together. I also glue cleats of scrap [1" thick] insulation board approximately every 24" under the track to prevent the track from sagging."

After 1 1/2 years of weathering outside, I would NOT recommend this technique for joining sections of track together. Because I live in a semi desert far from any source of air pollution, we have very clear skies. The sun is extremely hot around mid-day in the summer. The track gets so hot you can't hold your hand on it. Because of the high surface temp in the day, the plastic foam board expands considerably and then contracts during our cool nights. This expansion & contraction puts extreme stress on the joints. Also, even though the track baseboard is 1" thick, gluing a cleat every 24" is not enough to prevent the track from sagging between cleats.

For a track permanently located outside, I suggest using steel truss connector plates like the one in the photo below, along with lots of an appropriate glue between the joining edges and on the plates. Considerable pressure is required to press the plates into the foam board. Care must be taken to assure a tight joint with the wire perfectly aligned. Assuming the foam board is at least 1” thick, the steel plate under the foam board long the entire length of the joint will not cause a problem with the magnetically guided steering.



This plate is 3" x 6". I use 4 plates if the sections of track are 12" wide and use 3 plates if 9" wide.

Here is an update on baseboard material which I think is relevant. I have learned that 1" thick, 4' X 8' sheets of Owens Corning FOAMULAR extruded polystyrene pink insulation board comes in at least 2 versions. One is labled FOAMULAR 150, another FOAMULAR 250. FOAMULAR® 250 has a compressive strength of 25 psi maximum while FOAMULAR 150 has a compressive strength of 15 psi maximum.
Based on that information, I would recommend 250. It should be more resistant to denting and it probalby would withstand someone carefully walking on a magracing track on the grouind made of it. It should be an excellent material for making a poratble track. A 1" x 4' x 8' sheet of Square Edged FOAMULAR® 250 cost about $20. FOAMULAR 250 1 in. x 2 ft. x 8 ft. Tongue and Groove Insulation Sheathing cost about $10.50. The tongue and groove sheathing might be better yet for a portbable track.
Other companies make this type of insulation board. It is known as XPS insulation board.

You make a great case for 250, Ned. It makes sense. And it's not that expensive either.