Wattage ratings, myths, and other dubious things
Updated 4/5/98

If you already own a burner that claims to produce more than 40 or 50 watts of power, you may get upset while reading the following paragraphs. I'll apologize for any anger I may cause in advance, but it is not me you should be angry with..... Please note that stated wattage's are approximate, as line voltages may vary from place to place.

A couple of months ago I got hold of one of those "100 watt" power supplies, and tested it thoroughly. The results were surprising, if not "shocking"...

The most that I could get this so-called "100 watt" power supply to draw from the 110 volt A/C power cord (primaries) was 55.7 watts. And that was done using OUR specially made 16 gauge cord with one of OUR writing tips (#9). Using the same pen and same type of cord on our burner, produced 33.87 watts. The thing to notice here is that I used OUR 16 gauge cord and our #9 writing tip to do testing on both their unit and ours. The "100 watt" brand in question does not even sell their pens with the option of a 16 gauge cord. They use an 18 gauge cord EXCLUSIVELY.

In fact; when testing using one of their pens, cord, and power supply against our pen (#1HD, similar styled tip), HD cord, and power supply; their wattage was 38.86, while ours was 31.22 watts. Not only that, our tip got hotter (cherry red in bright sunlight), faster! "What is going on here?" you might ask. Both of the unit's wattage dropped. Theirs dropped allot (16.84 watts), while ours dropped about 2.65 watts. Why is their "100 watt" model only drawing 5 more watts than our 40 watt rated model?  Why is our unit getting the same pen tip hotter, faster, but drawing less wattage?!?

Why?!? Because you can only draw so many amperes through an 18 gauge pen cord (approximately 9 to 10 amps at 1.6 volts on our 18 gauge cord). A 16 gauge pen cord can draw about 14.5 to 15.9 amps at the same voltage. Another thing to consider is the pen tip itself. A pen tip with more metal on it can "draw" more amperage compared to a tip that is using a smaller diameter wire, flattened, shaped, and sharpened. Although more tip metal will also cause a tip to heat up slower, and not get as hot. Any modular connections between the transformer and pen tip also play a big part in a unit's efficiency.  A "bottle neck" found in any one of these connections will cause a shortage of power to the pen tip (this explains why our unit heated up the pen faster and hotter, while drawing less amperage from the wall socket).

At this point, we contacted the top person at the manufacturer of this so-called "100 watt" model, and asked how they tested the unit to get it to draw 100 watts (as we could not). We were told that if we looked at the labeling on the back of the unit, that it indicated "100 watts max" (as in "maximum" wattage, not nominal wattage). This person also said that they were able to get the unit to draw 100 watts by using a three foot (not the typical 5 feet they usually use) 14 gauge cord (soldered directly to the secondaries of the transformer), and a specially designed pen tip (Neither of which can be found at ANY dealer of their units, or even the manufacturer. They do not sell this configuration to the public). A large tip (no "choke point) with a 14 gauge wire welded to the transformer (no modular jacks at all) may be able to draw this kind of wattage, but it is hardly usable or practical.

So, what does this all mean? Well first of all, what a power supply "can" draw in wattage has nothing to do with how many watts are actually getting to your pen tip in the real world. First, anything rated beyond 40 watts is probably overkill. Second, "usable" wattage or efficiency; has a lot more to do with the pen cord gauge, length, modular connections, and pen tip design. Some other interesting factors are: how fast the cord dissipates heat (thickness of the insulator), resistance of the cord wire (quality of wire), length of the pen cord, resistance of the tip wire (metallurgical makeup), diameter of the tip wire (gauge), how much tip wire is being used (length/mass), how much of the tip wire has been flattened and shaped, tightness of modular connections (jacks), surface area contact of jack connectors, whether parts of the jack are solid or hollow, how well are jacks soldered to the cord wire, frequency of output voltage, and how many watts the power supply itself consumes.

"If this is all true, then how do they get such good heat recovery?" your probably now asking yourself. It has allot to do with a few important, and usually overlooked, things I just mentioned above. The manufacturer whom I have been talking about uses a slightly higher output voltage (2.09 volts) than our burners produce (1.6 volts). They also flatten more area of their pen tips compared to our tips (more heating area), use a much bigger diameter tip wire, and their tips are longer (more mass). They first have to use a bigger diameter tip wire in order to properly shape their tips after they've been flattened to get the larger heating area. They then need to output a slightly higher voltage in order to heat up this bigger tip. The extra flattened tip area in combination with a tip that is further from the pen body (has more mass), is where they are getting the heat recovery from. This approach has a few drawbacks of course. Bigger tip wire will cause you to burn a wider line, and the end of the tip is further away from the pen body (closer = more control). If their tips were allot shorter they would no longer have good heat recover, because their pen tip is "storing" excess heat which would otherwise travel to the pen body (what I like to call "the soldering iron effect"). Although imposing a higher voltage through the cord should "theoretically" up the wattage getting to the pen tip in some people's minds, it is negated by the fact that it will also increase the temperature of the wire, which in turn will make it flow less amperes.

At this point most skeptics, like me, might say "how can your analysis be objective? You manufacture and sell a competing product!". Well, as they say "the proof is in the pudding". If you or a friend owns a power supply that claims "100 watts" or more of power, just take it down to your local Radio Shack or local electronics expert with the largest pen tip you have available. Ask them to first measure the line voltage you will be plugging the unit into. Then plug in the unit, turn it on high, and ask them to put an ammeter around the A/C power cord. At this point, multiply the amperage by the line voltage to get your wattage. Voila, you've just done your own real world wattage testing. If this is not possible, just pick yourself up the "Power Carving Manual" that has a burner review written by Frank Russel (via Fox Chapel Publishing) and see what they came up with...

So, how does one go about choosing a burner then? What can you use as a benchmark of heat recovery if "wattage draw" is no longer an overall determining factor? Well, burner selection can be a subjective thing which changes from person to person, but here are some basic recommendations:

1: Look for a power supply that heats up its pen tips in a very "linear" fashion. You shouldn't have a burner that is too cold below a certain setting, and then too hot when the dial has only been moved a few degrees. i.e.: what is its usable range? Just because one unit heats the pen tip to 700 degrees at the "3" setting, does not mean that another unit that attains 700 degrees at the "5" setting is less powerful (it's all "relative"). It more likely means that the first unit probably doesn't have much of a "usable" range.

2: Look to see if you like the pen bodies, as well as pen tips offered. Are they comfortable to hold and work with? Can the tips do the type of work you want to do? Does the pen body heat up a lot after extended usage?

3: What is the cord like? Is it stiff and bulky, or light and flexible?

4: What special features does it have? Do these features have a usable function or utility?

5: Are any modular connections (jacks) tight fitting? If not, can they be tightened by you? Does the type of jack have a lot of surface area contacting its mate. If using connector lugs, are they soldered to the cord or just crimped? (BTW, quarter inch mono phono jacks cannot be tightened, and have very little contact surface area on female connectors)

6: Are the pen tips soldered in or replaceable? A replaceable tip may seem more economical, but it will be inferior to a soldered pen tip. Replaceable tips will eventually have problems with corrosion and intermittent heating qualities. If soldered, what kind? Some brands use 60/40 lead/tin solder to solder in their pen tips, and have to crimp the carrier so that the nichrome wire won't come loose. These manufacturers usually won't replace their fixed tips either (ask when buying), as they cannot remove the tips because of the crimp. Look for brands (like the Optima 1) that use"Silver Solder" to weld in their pen tips, as it is a stronger physical and electrical connection under high heat conditions, and can be retipped with a jewlers torch.

7: Are the wire connections inside the power supply "tag-soldered", "wrapped then soldered", or just crimped? Tag-soldering refers to putting any given wire in contact to a switch, jack, or lug connection and flowing the solder over it. "Wrapped then soldered", refers to actually wrapping the wire through the switch or jack connection point eyelet or around a lug connection first, then soldering. A wrapped solder connection is almost guaranteed to last forever.  Crimped electrical connections are almost guaranteed to fail within a few years.

8: How efficient is the pen and/or pen cords. Two plug compatible units that have the same "actual" (not advertised) wattage should be able to heat its competitor's pen (with the same diameter of tip wire, and same style of tip) to the same temperature using the same temperature setting on the same power supply. If the A brand pen gets hotter on brand B's unit (compared to brand B's pen on its own unit), it is more probably efficient. Conversely, if it doesn't get as hot it is less efficient. This test can sometimes be done with the pen cord too, if both plugs are the same. A polished pen tip will seem hotter when you burn, (as it will glide through the wood easier); so these tests should be done by burnishing/shading with the flat side of the pen instead.

9: Price! Remember, you do not always get what you "think" you are paying for! If at all possible, check out the unit you are considering at a carving show.

10: Warranty. What do they pay for (parts and/or labor), and for how long?

The bottom line is this: You can only put so many amperes through an 18 gauge cord at a given voltage. In order for anybody to get "100 watts" to a pen tip (at 2.09 volts), they'd have to put nearly 50 amps through that cord. This is a physical impossibility, ask any electrician....  Besides, if you could get 100 actual watts to a pen tip, it would last about as long as a 100 watt "cracked" light bulb (poof).

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