The track used to have a ramp-style section with foam tape on it, but was entirely too short for today's cars. I removed the lift blocks from under the guide rails, gaining about 3' of useable track that way, and cut the new strips to match the width. The new section is 4' long (for a 30' track) and from what I've seen, is definitely overkill. It uses the McMaster-Carr natural foam rubber, and usually stops the cars within the first foot.
I'd add a small bottom plate to minimize the distance cars have to fall if something goes wrong, but otherwise I'd not change anything.
Thank you all for the extra insight on sand paper between rear wheels. Won't do it this year.
McMaster-Carr was easy to deal with and the product was extremely easy to put on the stop section. Just cut to length and apply.
I'm going to test everything on Saturday. If it works, I'll post some pictures.
If it doesn't work, then I guess I'll go back to the drawing board...
- Master Pine Head
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- Joined: Fri Jan 27, 2012 7:30 pm
- Location: Kansas City, Mo
I would say most of the kids in our pack have thier weights glued to the bottom, very few put them internally.
Bottom-mounted weights are probably more likely to do damage (over the longer term) to the stop foam strips than to the car, unless the weights are not attached very well. To that end my "lanes" on the stop section are tapered a bit so that the initial transition has the foam below the top level of the lanes on the track.
- Darin McGrew
- Pine Head Legend
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- Location: Mountain View, CA
It has only been a problem for us for some of the trim weights held on with tape or hot glue, but our kits come with a dovetail slot in the bottom for molten weight, so the primary weight is secure.MOFAST wrote:Does anyone find having the track fall away, that weights are knocked loose?
On my own car I had a last minute pinch of tungsten putty in a hole in the bottom of my car that was slightly lower than the wood and it didn't rip off either.
First, an overall picture of the new stop section sitting on my kitchen counter:
I have two cars sitting on the stop strips for sizing. One of them has standard weights on the bottom and as you can see the wheels are quite nicely lifted off of the running surface.
The red car does not have any weights attached to the bottom. Without the stop tape on the lane the wheels are still touching the surface but there is only a millimeter or two of clearance between the bottom of the car and the top of the lane.
I bought 1/16th thick stop tape. I think if I had built this first, I probably would have gone with 1/8" instead. But since the tape comes in 50' rolls I can always put down a double layer if testing shows that the red car is sliding off of the end.
Testing will happen either this afternoon or tomorrow, not sure which at this point.
I will show pictures of how the new stop section attaches to our existing track later on to show the transition between the running lanes and the stopping lanes. Have to wait until the track is assembled for that.
I used 5/8" birch plywood for the construction. I purchased a 2' x 4' section from one of the local big box hardware stores. It's more expensive per board foot to buy it that way, but I didn't need any more than that. I ripped the board to the width of the track and then ripped the four lanes from what was remaining. The stop section is 4' long with 6" designed to rest under our current track, leaving the stop lanes at 3.5' long. The lanes on the stop section are tapered slightly (using a bench sander) where they meet the lanes on the current track. The current track appears to be 3/8" thick with 3/8" lanes. The track sits on top of another 3/8" spacer to keep it off of the floor. 3/8 + 3/8 + 3/8 = 9/8 or 1 1/8" total height. My new board is 5/8 + 5/8 for a total of 1 1/4" of height. I used the bench sander to remove a bit over 1/8" of material from the stop lanes so that they start below the surface of the existing track lanes when it's all assembled. The math doesn't work out exactly right but when I was done the lanes on the stop section were far enough below the other that the stop tape should be below the top level of the current track lanes. Even if it's not, it will be even or perhaps only a tiny bit over, and the cars certainly have enough clearance to make that work.
The new stop section has two coats of Minwax varnish. The top of the lanes on the stop section is unfinished as I wanted a bare wood surface where I could attach the stop tape.
The friction tape went on really smooth (with my wife helping) and it's really sticky! Not in an "eww" sort of way where it leaves a residue on your hand, but with a car on the tape I was able to pick the stop section up past a 45 degree angle and nothing moved.
As mentioned earlier I bought the 1/16" tape. Here's a picture of the wheel elevation from the track surface for a car with bottom weights:
And one without:
The red car has several millimeters of clearance from the surface of the track. If it turns out that some cars are too tall (have too much "ground clearance" for the stop section) then I will add a second layer of tape towards the end of the stop section. But for now I think it's going to work fine. I was really impressed with the stickiness of the tape. When I set cars on the stop section and slowly lifted one end up... here's a link to the video. I had my scout shirt on because we just go back from picking up bags for Scouting for Food this morning.
Friction Tape Incline Test
Here's a video (mp4 format only) of one test. My boys and some of our neighbor friends were having fun racing the cars down the track.
The purple "geaux" car was going the fastest but stopped the quickest because it has weights screwed on to the bottom, so the tape really grabs it. The green car on the right was second fastest and went the furthest down the stop tape because there's very little area that contacts the tape due to the design of the car. The car on the far left has a standard flat bottom, and the other purple car had a hollow bottom, but still more contact area than the green car.
- Stan Pope
- Pine Head Legend
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- Joined: Sat Jul 05, 2003 7:01 pm
- Location: Morton, Illinois
We have used full retired tempur-pedic pillows for some years successfully. This year I was tasked to fit 8 tracks, and only had 2 retired pillows. Time to subdivide those pillows!rpcarpe wrote:Some tempur-pedic type foam for the end of a brake section makes a great absorber of all that energy.
Here is what I did:
1. form an "L-shaped" housing from 1/4" plywood (3-1/2 X 12") and 1X2" pine 12" long.
2. Chill the pillows so that they are stiff, then cut the pillows into 3"X2-1/2"X12" bricks with a freshly sharpened chef knife.
3. Attach the pillow bricks to the plywood with Gorilla Glue.
4. Duct tape along the center of the plywood and under each each side of the track with gentle compression of the brick against the end of the stop section rails.
Key design logic:
1. the plywood keeps the foam pressed down about evenly on all or the lanes. ... car's can't get under the foam.
2. 1X2 helps keep the plywood stiff and keeps the foam from being "pushed out the back."
3. Low profile (for visibility) and minimal incursion onto the braking surface.
No problem seen during test runs of 3 of our fastest cars on a 4-section Freedom track and braking section. They just stopped with their noses still pressed against the foam! Each would have skittered well beyond the braking section otherwise.
I had intended to run parallel 1X2's over the stop and under the track and put carriage bolts / wing nuts on each end to "clamp" the stop in place, but I ran out of time and materials.
We will see how well this stands up to a full day of racing tomorrow... pix and report, I hope. Seven of the tracks will endure about 400 minutes of non-stop racing each. The eighth track will run Age Group Finals and the Race of Champions so it will be less stressed (but the scrutiny of any shortcomings will be much more intense.)
"If it's not for the boys, it's for the birds!"