Final heat, 2 minutes left, 12 laps up and then it happens - the car stops. An awful whining noise breaks your heart - you know what it is. The marshal throws your car over and sure enough the pinion is spinning on the armature shaft. You try to solder it back on as fast as you can and all you manage to do is melt the spur. The heat ends and you're last again. If this sounds all to familiar, SlotSide can help!
- The step-by-step method to make sure your pinion never spins.
- Armature shafts are filthy. Clean it with heavy duty brake cleaner. An aerosol can that should last at least 1000 years costs about $5 at the automotive shop.
- If you're using a ball bearing motor, be sure you have a phenolic on the shaft before you go any further. If you are using a can with an oilite in it, don't worry about it.
- Apply a small amount of acid flux to the shaft with a small paintbrush (only use this paintbrush for acid flux).
- Melt a small amount of solder to the tip of your well heated iron and immediately bring it in contact to the entire circumference of the shaft. Be careful not to get solder in the bearing or oilite!
- Prepare your pinion. Inside of pinions are filthy. Clean it. After using brake cleaner, get a small circular file that fits into the pinion and rotate. With the dedicated acid flux paintbrush, paint a small amount of acid flux inside the pinion.
- Place the pinion over the end of the tinned shaft. It should not slide onto the shaft because the solder expands the armature shaft to greater than the inner diameter of the pinion.
- Clean every bit of solder off your iron. Failing to do so will result in solder all over the pinion. If you do somehow get solder in the teeth, Rudy Gariga of Slick 7 products made an excellent suggestion. Heat up the pinion with a soldering iron with the motor hooked up to a power supply. Once the solder in the teeth has turned to liquid, remove the iron and let your motor rip! Close your eyes to avoid getting solder in them. You'll open them to a brand new pinion!
- Put the hot iron over the pinion and gently push it down onto the shaft. As the solder melts, it should slip on easily.
BULLET PROOF!
Back to bullet proof index
Back to tech index