New Hope for Steam Power: Tank Etching and Electrical Work

Honestly, I had no idea what I was doing when I began this project. My only prior experience was the small engine I had built previously (and described in this series) and some self-taught motorcycle maintenance. Neither, however, can fully prepare you for the realities of working with steam power. It's powerful, dangerous stuff and can get out of control uneasily unless you've done your research and included all the necessary safety devices to keep things in check.

Safety First

Most important among these devices is a pressure relief valve, which automatically vents the system when the pressure reaches a pre-set point. There are also heat- resistant valves and tubes. The annoying reality, however, is that it isn't easy to find plumbing fittings that are rated for this kind of service. Home Depot and Lowe's don't exactly cater to the steam vehicle crowd, and I wound up doing dozens of hours of research on material properties and specialty shops in order to find what I needed. (But I'll get into that at a later date.) To continue my progress then, I decided to go ahead with restoring the frame and peripherals.

Cleaning and Lining the Tank

The next step was preparing the electrical system and former gas tank for their new roles. The cheap tank that I got for this project was a complete charity case. Most of the paint was displaced by a thick coat of rust, and the multiple dents in the surface had reduced its capacity by at least a half-gallon. It was cheap and solid, however, so I lined the interior with a water-proof polymer to prevent rust, sandblasted the exterior, and spent over two weeks spreading and sanding body filler.

As a brief FYI, it is extremely important to use the correct acid for etching the inside of the tank before lining it. This is necessary both to clean out the rust and give the material a clean and rough layer to adhere to. I mistakenly used muriatic acid (dilute hydrochloric acid), which later caused the polymer layer to completely peel off. When etching steel, be sure to use phosphoric acid, which is available from Tractor Supply Company as Milkstone Remover.

Powering the Pump

After restoring and mounting the gas tank, I needed to address the electrical system. I wanted to use an electric water pump as the boiler feed, so I needed to build a suitably robust system to handle the strain. Originally, I wanted to build a 12-volt system that recharged from the motor's alternator, but unfortunately the XL185 uses an incompatible 6-volt system. Luckily, the pump I chose would take over an hour and a half to deplete a standard motorcycle battery. So I built a total-loss system instead, using spare Honda handlebar controls as the pump and light switches.