Showing posts with label broken scalextric wire. Show all posts
Showing posts with label broken scalextric wire. Show all posts

Saturday, 6 January 2018

Scalextric parts contacts and silicon wire for G38 round guide plates

These Scalextric guide blade contacts with high flex silicon wire attached are direct replacements for the original Scalextric parts used for the modern round guide plates. These contacts and wires have been used extensively on Scalextric cars from 2003 to the present. These wires can be soldered to the motor tabs directly or joined to the existing pick-up wires.

 Scalextric wires


These contacts are suitable for the Scalextric Start range of cars.
This Scalextric guide assembly is sometimes referred to as G38.


Replacement Scalextric guide kits are available
Replacement guide plates with braids fitted are available

Scalextric spare parts from Scalextric Car Restorations

Thursday, 16 February 2017

Crimp Failure at Braid Contact on Scalextric cars from 2016 onwards

Introduction

For a scalextric car to operate the electrical current must flow into and out of the car. That's two discrete electrical connections. To do this the slot rails in the track are the two conductors. The electric current connects to the car via the flexible woven braids fitted to the guide blade, then to the braid contact plates and then through wires to the motor. The rotation of the guide blade for corners and the like is managed through the use of the flexible wires.
The wires need to be securely fixed to the braid contact plate to make the electrical connection and to withstand the regular rotation of the guide blade.
Recently (we believe sometime in 2016) Scalextric introduced a change in the way the wire is crimped to the braid contact plate. This is the silver coloured plate that makes contact with the braid. There is a very serious problem with this new design of crimp.
There is insufficient length to the crimp fingers to fully secure the outer insulation of the wire. With the action of the guide rotating over time the wire pulls out of the crimp. This breaks the electrical connection between the wire and the braid contact plate.
Once the crimp has failed the Scalextric car stops on the track.
Scalextric G38 round guide blade
Damaged Scalextric crimp to wire
Here is a close-up picture showing the failed condition. As this is a design based problem the repair is not as simple as it might appear.
Option 1. Simply re-make the crimp. This will last for a short while until the crimp fails again.
Option 2. Just crimp onto the conductor wire strands. This will last for a short while until the wire strands break through the action of metal fatigue.
Option 3. Solder the wire to the braid contact plate. This doesn't work as the latest braid contact plate is plated in a material that doesn't take solder. There'd also be the strain relief problem.
As shown in this picture to make the electrical contact the insulation is removed and the end of the wire strands are tinned with solder and bent back over the insulation. That's why the electrical contact fails once the crimp fails.
As this is a design based problem the solution must also be design based. That means a new design of connection.
Scalextric wire connection
Replacement Scalextric wire connection
The solution is to use a new braid contact plate made from a slightly stronger steel that is plated with a thin layer of brass. This will take solder.
To overcome the lack of strain relief with this soldered solution a short length of ultra-flexible silicon wire is used. This wire consists of 128 strands of 0.05mm diameter copper and a silicon insulating layer.
This is flexible enough to easily withstand all the movement of the guide blade.
Here is the repair complete in the Scalextric car. The original green and yellow wires are shortened to make the room for the silicon wire tails. The joints are soldered and a length of insulating tape covers the exposed joint.
We freely admit this isn't pretty but it does use the right materials in the correct Engineering environment.
Stronger brass plated steel braid contact plates. Solder joints. Ultra-flexible wire where the wires are needed to move regularly.
Scalextric car repaired

About the author:

Gary Harding has been working with Scalextric cars for over 35 years and now operates Scalextric Car Restorations in the UK. Scalextric Car Restorations is a Worldwide internet based business that offers for sale high quality Scalextric cars and Scalextric parts from the 1960s to the present day. All the restoration work is carried out to the highest standards with the highest quality parts available. Only the best cars are selected and the final result is a car that is genuinely like new.
Further help and advice relating to this article or Scalextric cars in general can be found at:
http://www.scalextric-car.co.uk

Thursday, 14 January 2016

New Scalextric cars and the guide blade contact failure

A growing problem with the newer Scalextric cars with the round guide blade is the connection between the contact piece and the motor wire breaking.  It also seems Scalextric know about this as they have used different techniques to make this connection since this round guide was introduced.
Scalextric guide blade
Initially the contact was a solder connection but this causes the wire to fracture adjacent to the solder joint.  This is caused by metal fatigue due to the constant movement of the joint and corrosion caused by the solder flux.
Then there was a phase of crimping the joint, which is technically the best way to make a joint of this type.  However, the crimping was not done properly so the wires would just pull out of the crimp.  Now there is a crimp and solder process, but soldering a crimp is difficult so the solder doesn’t always secure the joint properly and the wire just pulls out again.
The final problem we’ve seen is that the contact itself can snap between the crimp and the guide.  This is because the metal is too thin for the job, which might explain the failures of the crimp only jointing method.
We have available a replacement contacts that are made of thicker material with a solder tag to make the joint to the wire.  This is a direct replacement and upgraded part.  Also, available is a complete guide with wires already attached.
Another great insight from Scalextric Car Restorations