It Worked !!!

Two potential problems: firstly, there's volts applied, and that can accelerate corrosion (of the tank, the pipes, or even buried exterior pipes). Any changes (new water heater, somewhere down the line) can change your circuit, too. Second, the toilet tank/bowl might also be freeze-able.

Me, I wrapped some heat tape around the pipes that get coldest, and I'm happy with that. Tiewraps and an oversheath of snap-on insulation are also applied. That only applies to some crawlspace in my case, but in yours a bit of heat (like an electric thermostat/fan gizmo) could make your restroom more cold-friendly.

Thanks for the reminder! I've just verified that the heat tape is working (drawing power), with a handy Kill-o-Watt. It's something of a comfort to know that the years haven't undone that precaution.

Thermostatically controlled pipe heaters start at under $20.

Used to be a common practice to thaw pipes on the farm with the old "buzz-box" lincoln TombStone welder. Set it to a low current ,, connect the cables, turn it on and walk away. You knew the job was done when the water found it's way out of the split pipe - - - -

I'm looking for inconspicuous trim screws to replace the tiny ring nails that held on window and door trim I removed to upgrade the insulation. Everything I've found has a head many times larger than the nails'.

If an industrial appearance is acceptable "wafer head" screws may be the answer.

-jsw

WHen I lived in Huntsville, we lived at the base of Monte Santo Mountain an d the house was sitting on limestone. Unfortunately the water line ran und er the car port and was not insulated. BUt it was metal pipe. So when it was really cold it froze under the cement. And I did pretty much the same thing. Except for using a welder instead of a battery charger. It did not freeze every year so I never made anything more compact. I expect it does not freeze every year where you are, so hardly worth the effort to make so mething dedicated .

Dan

Trim head deck screws might be good there, and they come in colors. Some are self-drilling, others would require a pilot hole for trim to prevent splitting.

It does freeze here every year. Less so on average each year though... Eric

The bathroom doesn't get cold enough to freeze. It's cold coming from the outside that is freezing the pipes. To wrap the pipes I would need to cut open the walls, which I am loathe to do. The pipes I'm energizing don't go underground. And the hot water pipe is shorted out to the cold water pipe before the water heater. So I don't think any power is running through the water heater. Eric

Martin

Agreed, I have a DVM that reads 5 Ohms or more with the probes shorted.

OTOH, I've measured the drop in milliVolts across the 12 AWG wiring to my solar panels while passing 1.00A or 5.00A through it, and then for comparison measured the wire resistance with this meter .

-jsw

Funny how everyone forgets the resistance of the multimeter leads.

We used a welder every day for preheating the discharge pipe on the mag pump. The pipes had welded on tabs just to provide a place to clamp the leads. This was to pump molten magnesium from the collection well in the experimental electrolytic cell into the crucible car below.

I redesigned that pump. The original used air motors, angle iron frame, about a 6' shaft to the impeller with graphite bearings every couple feet. I went with a shaft tapered from 2" to 1/2", no bearings, and a belt drive to eliminate an in-line connection to the motor. Eliminated most of the maintenance.

That's the first time I ever saw a taper attachment. I had designed the shaft with a series of steps, and the shop guys called me over and asked if a taper would do, since it was a lot easier to cut with the taper attachment. Designing stuff, then getting to spend time with the machinists in the shop was where I really got the bug.

Pete Keillor

For comparison, the battery charger I made from a Powerstat and a "50A" welding transformer delivered 18A at 36.9V in the full load current vs output voltage test. My goal was 20A at 28V for at least

-jsw

snip

He's lucky he checked his water bill - - - -

Too cool to mold - and drycore and the carpet tile he used are mildew resistant. A bit of mildew/mold on one piece of "termite spit" shelving.

Shrink the oratex fabric on the plane.

Just make sure whatever power supply you use is fully isolated - in other words don't just connect a Variac and dial in the power required. Also make sure whatever transformer you use is rated for

- like a fan.

I found that the welding transformer I turned into a power supply could output 1/2 of its max rated current @20% duty cycle continuously without overheating. The hottest measurable area was the primary winding and its temperature depended only on input (and output) current, not voltage or load resistance.

The transformer core impedance (iron loss) was nearly constant up to to 100V in and not excessive below 125V, but the Variac shouldn't be connected to apply 140V to the transformer.

-jsw

That sentence doesn't read correctly. The ratio of primary current to voltage held nearly constant at ~10mA/V up to 603mA @60V. Above there the current rose increasingly faster than the voltage, reaching 2.3A @120V and 3.0A @125V. At 140V in, the transformer no-load primary current was 6.1 Amps.

In simple terms this means you should be careful about leaving a welder short-circuited. I haven't measured any other machines to determine how much abuse they can take.

-jsw

Again, very lucky.

Oh, so that's how the fabric airplane wings are fashioned. I've often wondered.