Experimental Fun

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This high powered back massager is my latest project surprisingly it was nearly harder to make than my fusion reactor, but that's another story... despite what it may look like it is going to be referred to as a back massager on my website. It has been custom made as requested for a friend of mine so extra quality control and safety measures have been taken into account to make sure it will be durable and safe.

The back massager is up to 3X as powerful as anything available in stores or online, absolute max power is 75 watts. For safety and durability it has a recommended setting of High and to never go past this setting to Max. The High setting will power the motor with approx 7.0-7.3 Volts and on the Max setting the motor could be supplied with up to 12.0-12.5 Volts. The motor that was used is rated for 18Volts however it was removed from a 24Volt GMC drill... The massager is made of a combination of Stainless Steel and Aluminium, the whole massager has been coated in approx 3 coats of clear coat to prevent any tarnishing

I was originally going to use the gearbox that was attached to the motor as it had good bearings in it that would make it very durable, but it was too thick and the output speed was going to be too slow.

A piece of stainless rod and a screw was used to off balance the motor to cause it to vibrate. Also a screw is screwed onto the motor shaft the prevent the un-balancer coming off.

Someone was generous enough to give me a beautiful piece of stainless tube which was the perfect length and diameter. I came up with the idea of using a stainless door knob welded to the end of the tube for a nice smooth finish. But once I started welding the door knob on I found out it wasn't nearly as thick as what it seemed. To save costs when making it they put a thin layer of stainless over ordinary mild steel. So I ended up soldering it on to the SS tube.  

The tube came up nicely once sanded lightly, the soldering was tested for any leaks or holes. 

The motor was placed inside the tube ready to be spot welded in. This turned out to be the most tedious part of the project, as I had to be careful not to damage the heat sensitive magnets inside the motor. Since welding produces quite a substantial amount of heat and heat damages magnets.

The end cap had to be welded on the end of the tube very carefully as to not damage the plastic electrical cord going to the motor, some thick heat shrink was shrunk around the cable to reduce any damage to the cord, heat shrink has a much higher melting point than standard plastic cord sheath.

The massager was sanded to remove most of the scratches. 

Then it was polished to get a nice shine, the polish was removed with a few wipes of acetone to make sure it didn't cause any problems withe adhesion of the clear coat that was to be applied. A decorative aluminium curtain rail end was used as a handle.

The control box was the next step, it ended up significantly bigger than I first anticipated. This was due to the PC power supply that needed to fit inside the box. The 12V motor speed controller didn't take up too much room. All the unnecessary wires were trimmed isolated and tied back out of the way, as there is a few different voltages available from the power supply and I only needed to use the 5Volt and 12V power output from the power supply. The power supply can output up to 8 amps @12V and the massager uses on the Max setting between 7-8 amps, since this setting won't be used, it won't matter that it is so close to the maximum available draw on the power supply instead it will draw around 5.5 - 6 amps on High.

Almost done, as you can see the mains voltage is contained inside the earthed metal power supply for safety reasons. A USB port was added for laughs. The power supply has a built in fuse and the 12Volt output will have a replaceable fuse on the side of the box.

The specification chart on the power supply.