Guides &
Braid
Tape vs Braid
Michael D. Zimmerman
Sr. wrote:
Hi Cory,
Save yourself some future aggravation and do it right the first
time with braid. If you're talented enough to build the track
and rout the slots, it's not that big of a deal to rout the extra
groove for the braid. Once you do the main slot, you're 70% there
anyway. I've built tracks both ways and copper tape is a headache,
especially after it ages. It will split, corrode, tarnish, curl,
wrinkle and the connection is not as good. Just remember when
setting up your equipment for depth and the like, you always want
to have a test piece to do first, even if you think it's correct,
it may not be. The test wood is the only way to make sure. Once
you get it set right, you can do
the whole thing. Preparation is everything. Make sure to allow
for whatever adhesive you are using for the braid. This will account
for a millimeter or two. I used hot glue on my 110' road course
in 1986 and have yet to see any of it, anywhere even begin to
lift. Never a problem. It was laid right on the bare wood. Don't
paint under the braid. I laid down about a 1/16" diameter
bead in the center of each braid groove and then came back later
and laid down the braid with a big plumber's soldering iron with
the tip ground to match a guide flag with a shallow rudder. You
will need two people to do this. Remember to try not to stretch
the braid around the corners. Lay it down flat and give yourself
plenty to work with otherwise, it will pull up later on. Make
your braid grooves wide enough so that the braid will not hang
over the main slot. This will cause the cars to pull it up eventually.
I always try to keep the braid just a hair away from the slot.
If you do this and keep it as close to track level as you can
and not too high, it will last almost forever.
Hope this helps
Mike Z
I agree with just about everything Zim says about tape. Routing
the recess for braid is no work at all - the main problem is acquiring
or making a piloted rabbet bit to fit in the slot. Any machine
shop could make one up for you but I followed a tip by Pete Sardella
and made my own. I took a flat bottomed carbide-tipped 3/4"
rabbet bit and simply drilled a 1/8 hole in the bottom. This was
soft enough and no trouble to drill using a press. I soldered
in a short piece of axle for the pilot and voila -- worked great!
If you use standard 1/4" wide braid, the 3/4" width
of the bit is just about right to give a little space etween the
braid edge and slot. I glued the braid using contact cement and
have had no trouble at all with it lifting. The glue was a bit
of a pain to apply to the braid (I used a squeeze bottle and
small spatula to spread it on), but once dry placing the braid
was easy, and didn't require a soldering iron with special tip
or even two people to do it. But whatever method you use, I can
only amplify Zim's advice.......preparation is everything.
mp
Routing for Braid
We have had that problem, too, with finding the correct bit to
use. We gave up on that fairly early and came up with a homemade
plate that bolts to the bottom of our router. It has a 1/8"
pin on each side of the center shaft of the router. These are
set as close together as possible so as to not have problems cutting
too far to the inside on turns. It works very well so you need
only to install a standard 5/8", 11/16" or 3/4"
bit, or whatever you are using. There are many methods to do the
job correctly, it is just what seems right for the individual.
I have always taken advice from numerous people on everything
I do, then condensed it into what I thought was
right, added in my own stuff for good measure and went with it.
Bottom line is, if you can work with your hands and you put your
mind to it, you can do it, and do it in a manner that works the
best for you.
Mike Z
I remember something
being said about how to 'properly' prepare pickup braid but never
saw the discussion. I thought I would share what I recently discovered.
I have been using a brass wire brush (like a toothbrush, comes
in a threepack with steel and plastic for about $2 to clean and
separate pickup braid. It removes the oxidation (dirt) and unbraids
the ends of the braid, which , I think, is what is needed for
good contact. I also have been using Marvel Mystery Oil penetrating
oil. I think that's the name. It comes in a red plastic bottle
with black printing. They make a regular oil also, but the penetrating
oil is the one. Just the smallest amount on each braid very infrequently
does the job. It really works well on older corroded braid after
the wire brush. Be careful not to get too much oil on the track
this way, although it did 'recondition' my old Revell track. Another
trick I have been using that I discovered for HO cars and works
great for larger
scales, is to use duct tape to clean the tires. Just unroll enough
to reach back around the roll of tape and reattach to itself,
then roll your tires clean. A few laps will clean a dusty track
and I have never found any sticky residue on the track with even
the cheapest duct tape.
Depending on the tire, you may find duct tape is too aggressive.
For example, to me it appears that duct tape actually pulls bits
of rubber from a Ninco 70140 tire (rather than just removing the
dirt) leaving the tire with small pits. I find that packing or
masking tape is
sufficient to remove the dirt but does not harm the tire. I find
that for built up dirt on guide braids that electrical contact
cleaner removes the grunge. An ordinary Pink Pearl eraser can
then be used to keep the braid clean. I use a pin to pick apart
the end of the braid to make it more pliable and hopefully provide
better contact. The oil is Marvel Mystery Oil and can be found
at most auto supply stores. It has been a slot racer's friend
for many years.
Tom Moye
On Wed, 10 Apr 2002
10:43:25 -0400 Michael Paschal <mpaschal@aasianst.org writes:
One last chance to offer my certainly uninformed and probably
ill-advised comments to the tripod discussion. Conventional wisdom
states that 1) front wheels are irrelevant except to act as outriggers
in hard cornering, and 2) chassis weight should be born by the
guide shoe. Obviously there should be adequate weight to maintain
brush to braid contact and keep the guide in the slot. It seems
to me though, that applying the full weight to the guide, i. e.,
having the front wheels NOT touch, would tend to increase friction
and slow a car down. Theoretically at least, wouldn't having the
car's weight partly supported by the front wheels (assuming they
are round) reduce friction and thus increase overall speed? Having
the weight roll rather than be shoved or dragged I think was discovered
to be the way to go several thousand years ago. Of course, Rocky
or Al would remember that time better than I.
mp
Again, why this is
a problem
1)tracks are rarely
smooth enough to have the braid in PERFECT contact the whole way.
a. acceleration, and brush tension lifts the front of the car...
wheelie. Every track irregularity lifts the wheels AND the braid.
2)With the wheels on
the track they WILL steer you out of the slot. See all this is
predicated on the idea that the guide shoe is just a piece, actually
keeping the guide permanently in the slot is the SLOT CAR part.
3)Friction: sort of
not the right term, actually friction goes up with less contact...
eg a Knife blade. The guide is pretty low drag, the braid as well.
Simply, the whole thing becomes irrelevent if you are not making
good contact. Look at this, how about pulling the spring tension
off the motor brushes. Drag will go down, speed will go UP. Try
that! same with the guide, it runs better with the right amount
of pressure on the contacts. But belive what you want. I would
be happy to have someone prove me wrong
Fate
Last night I was working
on a chassis for the upcoming Las Vegas meet Pre-1965 front engined
Le Mans car with no magnet) and I decided to fit one of the new
Slot-It guides for a routed track. I like the forward positioning
of the guide post and the eyelet attachment for the wires. The
sheet steel chassis that I was butchering has a stamped guide
hole - too big for the Slot-It post and too thin to
provide accurate positioning. I popped an axle bearing out of
a defunct Pittman 703, bored it 3.5mm, turned it down to fit the
chassis hole and soldered it in place - perfect fit. With the
chassis in running order, I wanted to test it. My Scalextric
track will not accommodate the guide as I expected. Before cutting
down one of the Slot-It guides to use as a test system, I decided
to try one of their plastic
track guides. These have a slotted snap-in post like the typical
Euroscale car. It snapped in perfectly! I now have a system that
appears to satisfy two important criteria: The forward post maximizes
the effective guide base while keeping the guide under the nose
and the
compatibility of the two versions allows me to convert from plastic
to routed track in a matter of minutes.
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