Electricity: where is 208 volts used?

Self-tutoring about wiring: the tutor inquires about where 208V supply might be found.

Looking at the baseboard heaters the other day, I noticed they have two wattage ratings: one if in a 208V system, and one if in 240V.

I assumed this house is 240V, and even confirmed so at the source panel. Yet, I reflected, 208V must exist, and even be fairly common, if the baseboard heaters mention it.

Apparently, 208V is common in commercial buildings in North America.



Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Diy: can new silicone be added over old?

Diy self-tutoring: the tutor explores the idea of redoing a silicone seal.

When a silicone seal gives up, or likely soon will, it needs to be repaired.

Can you apply new silicone over top an old seal to fill a crack that’s developed, for instance?

The associate at the hardware store tells me no: you can’t add new silicone on top of old. Therefore, to repair a silicone seal, you must remove it, clean and prep the site, then lay down a fresh one.




Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Handyman role, home maintenance: (at least some) LED bulbs not for installation in completely enclosed fixtures?

Home maintenance, for me, requires constant self-tutoring. The tutor mentions a message he saw on the label of some LED bulbs.

I long ago heard that LED bulbs would produce comparable light – or even brighter – for a fraction of the energy needed by incandescent bulbs. Last night I installed one and the claim seems true: at 9.5W, the light seems to produce at least as much as I’d expect from a traditional 60W incandescent bulb.

Yet, a directive on the box of the LED bulbs says “not for use in totally enclosed luminaries.” I wondered what it meant, and why. All I could imagine was that heat buildup in an enclosed fixture might compromise the LED function. Yet, isn’t the point of LED bulbs, that they barely produce any heat, so therefore are very efficient?

On the internet I went to diy.stackexchange.com and got an answer I’m happy with:

Yes, it’s true the LED bulb shouldn’t be used in a completely enclosed fixture, if the box warns against it. The reason is that, while LED bulbs barely produce any heat, they can be VERY sensitive to heat, so may not function optimally in their own waste heat. An open fixture will allow the heat to escape so that the LED’s function will be promoted.

Fortunately, the fixture in which I wanted to install the LED bulb isn’t completely enclosed: I went ahead with the installation.


Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Handyman role: hinge measurements

Taking on the handyman role leads to self-tutoring: the tutor shares a discovery about hinge sizing.

At possibly around 20 years old, little things on a house can need replacing. Such was the case with the spring hinge on the door between the garage and the shoe room.

I sized the hinge, then went to the hardware store to seek a replacement. I knew I needed a 4″ hinge. However, the measurements on one package said 4″ by 4″ by 1/4″, while the other said 4″ by 4″ by 5/8″.

The measurement at the end, 1/4″ or 5/8″, stumped me. I couldn’t recognize anything that could be that measurement. Furthermore, I feared choosing the wrong one – whatever that measurement might mean – would turn out problematic.

My conclusion is that 1/4″ or 5/8″ means the radius that the mounting plate corners are rounded. I measured the rounded corners of the one to replace; they indeed have radius 5/8″. I bought the 4″ by 4″ by 5/8″ replacement spring hinge, and successfully installed it.

Looking at the spring hinges, I was imagining their functionality, so didn’t think, at first, about their decorative features.


Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Gutter maintenance: a quick fix

Home maintenance is another area of self-tutoring. The tutor shares an improvisation.

I’ve always used gutter baskets, but I’m having trouble finding them locally. I had to replace a rusted-out one, so wondered what to do.

I happened to have some metal screen in the shed. I cut a strip out of it, then laid it over the downspout like so:

Next time I clean the gutters, I guess I’ll see how it works:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: handyman role: how to remove a tight lag screw (hopefully) in one piece

Yard work is constant self-tutoring. The tutor shares an observation from it.

Today I was disassembling some reinforcements made last fall for an abandoned project. The reinforcements were triangular, consisting of landscaping ties and 2×6 boards fastened with lag screws. They had purposely been made heavy and strong.

I began to loosen one of the lag screws; it started to turn with much difficulty. Suddenly, it turned much more easily: I knew it had twisted apart. It didn’t do so at the head; I still had to turn it out. However, only the top inch or so came out, while the bottom remained lodged in the wood.

I didn’t think any of the other lag screws would twist apart; rather, I believed the one that did was defective. When another one twisted apart the same way, I decided to change my method.

The next lag screw I turned slowly through short arcs with pauses in between. It stayed whole, as did the others I so removed.




Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Weather: snow accumulation: mass of snow on the deck

The tutor mentions a consequence of the recent snow event.

Here, we’ve had an unusual amount of snow lately. I cleared off the deck two days ago to relieve it from the mass of snow on top. Then, from the night before until yesterday evening, we received about 18 inches (46cm) of fresh snow.

Last night I wondered again about the mass of snow on the deck, so I estimated it as follows:

deck area: 20’x10′ = 200sq. ft.

A foot is 30.5cm, so a square foot is 930cm2.

Therefore, the deck area is 200x930cm2 = 186050cm2.

The height of the snow is 46cm. I’ve heard 10cm of snow is equivalent to 1cm of rain.

Hence, the equivalent volume of water on the deck is 186050cm2x4.6cm = 855830cm3.

Perhaps surprisingly, 1000cm3 = 1 litre. It follows that the deck is holding 856 litres of water.

Furthermore, 1 litre of water has mass 1 kg: the mass of snow on the deck is 856kg, or about 1900 pounds.

So, after a heavy snowfall, the mass of snow on a structure can truly be significant.

Good luck with your snow clearing:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: opening jars: why a cloth or glove might help

The tutor talks about why using a cloth or rubber glove might help to open a jar.

I’m not particularly strong, so with household chores I have to improvise sometimes – for instance, when opening jars.

When I was a kid I knew that a rubber glove could help with opening a jar; today I know that, in many cases, wearing the rubber glove isn’t as helpful as wrapping it around the jar. The other day I finally wondered why.

The reason is that often, lack of grip isn’t the problem opening a jar; rather, it’s lack of mechanical advantage. As the grip distance from the jar increases, you get more leverage. In many cases, a thick cloth might work even better than the rubber glove, because it pushes your grip further from the mouth of the jar, possibly increasing your leverage even more.

I’ll be talking more about little household tricks as I think of them:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: toy repair with J-B Weld, part II

The tutor continues about a toy repair, with some reinforcement ideas.

While we were repairing the toy a few nights ago (see my previous post), my father-in-law suggested that, after the first repair cured, a second application should be considered around the outside. Such reinforcement, he commented, would give the repair its best chance of holding.

I considered his counsel from an engineering point of view: how much extra strength could we anticipate from application of J-B Weld around the outside of the repair site?

Let’s imagine the shear force to be straight forward. The strength of a reinforcement can be, generally, proportional to its left-right length multiplied by its height, then by the square of its forward length. Assuming the J-B Weld works as an integral piece after drying, I imagined an outside application along each side plane. The application would be about 20 times the height of the original shear, then its same forward length, but only about 1/30 of its left-right length. Compared with the first repair reuniting the two sheared surfaces, the reinforcement strength per side might be 20(1/30) or 2/3. Both sides together could offer reinforcement strength of 2(2/3)=4/3 or 1.33 times the strength of the original repair, more than doubling its shear resistance.

With these numbers in mind, I took my father-in-law’s advice and made the reinforcement application about 24 hours ago. The repair should be ready right now.

I’ll be sharing more about this fascinating toy repair:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Lifestyle: toy repair w/ J-B Weld

The tutor wonders about a pending toy repair.

My younger son has a toy he really loves that broke. Specifically, a pot metal part sheared off. It’s a toy out of production, so can’t be replaced.

Looking at the breakage, a repair seemed unlikely to work. I went to the hardware store and explained the situation. The man handed me J-B Weld: “If anything could work, this will.”

The J-B Weld label suggests a tensile strength of 3960 psi. The tensile strength of pot metal might be around 40 000 psi. In the toy, the strain on the metal part is not tensile, but rather shear. The shear strength of pot metal is around 75% of its tensile; if the same for the repair, it might be around 3000 psi.

I estimate the surface of the repair to be about 1/64, or 0.015625, inch2, suggesting a repair strength of 3000(0.015625) = 47 pounds.

The pot metal part stretches an elastic. Stretching the same elastic even further by a hanging mass, I’ve determined that the toy’s pulling force is less than 2.5 lbs. With estimated strength of 47 pounds, the repair should hold.

J-B Weld needs 24 hours to cure; the repair has had about 36. I guess we’ll know soon if it works. I’ll keep you posted:)





Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.