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Wire Chart



AWG       D.C. OHMS     WIRE DIAM   APPROX. TURNS PER      FEET PER
SIZE     PER 1000 FT     INCHES     INCH, SOLID ENAMEL      POUND
                                    COVERED
 1        .1264          .2893         X                    3.947
 2        .1593          .2576         X                    4.977
 3        .2009          .2294         X                    6.276
 4        .2533          .2043         X                    7.914
 5        .3195          .1819         X                    9.980
 6        .4028          .1620         X                   12.58
 7        .5080          .1443         X                   15.87
 8        .6405          .1286         7.6                 20.01
 9        .8077          .1144         8.6                 25.23
 10      1.018           .1019         9.6                 31.82
 11      1.284           .0907         10.7                40.12
 12      1.619           .0808         12.0                50.59
 13      2.042           .0720         13.5                63.80
 14      2.524           .0641         15                  80.44
 15      3.181           .0571         16.8                101.40
 16      4.018           .0508         18.9                127.90
 17      5.054           .0453         21.2                161.3
 18      6.386           .0403         23.6                203.4
 19      8.046           .0359         26.4                256.5
 20     10.13            .0320         29.4                323.4
 21     12.77            .0285         33.1                407.8
 22     16.20            .0253         37.0                514.2
 23     20.30            .0226         41.3                648.4
 24     25.67            .0201         46.3                817.7
 25     32.37            .0179         51.7               1031
 26     41.02            .0159         58.0               1300
 27     51.44            .0142         64.9               1639
 28     65.31            .0126         72.7               2067
 29     81.21            .0113         81.6               2607
 30    103.7             .0100         90.5               3287
 31    130.9             .0089         101                4145
 32    162.0             .0080         113                5227
 33    205.7             .0071         127                6591
 34    261.3             .0063         143                8310
 35    330.7             .0056         158               10480
 36    414.8             .0050         175               13210
 37    512.1             .0045         198               16660
 38    648.2             .0040         224               21010
 39    846.6             .0036         248               26500
 40   1079               .0031         282               33410
 41   1323               .0028
 42   1659               .0025
 43   2143               .0022
 44   2593               .0020
 45   3348               .00176
 46   4207               .00157
 47   5291               .00140

************************************************************************

 For winding Tesla secondary coils the general consensus is to use 
 number 22 AWG, or larger diameter, CLOSE WOUND MAGNET WIRE. Often 
 surplus partial spools of odd wire sizes are found, so I took time 
 to post a more complete chart of AWG numbers and fractional diameters 
 than is usually available.  All information above is approximate 
 despite the decimal places. Wire diameter, turns per inch, resistance, 
 feet per pound, etc. all vary slightly from one manufacturer to another. 
 Insulation thicknesses will vary depending upon type and the supplier. 
 Turns per inch will also vary with the quality of the winding. In 
 practice, Tesla coil windings are not perfect (nor do they need to be) 
 so expect some slight variations from the specification table above.

Thanks to Ed Harris for the insulation information below :

Magnet wire coatings from Phelps-Dodge: All data pertain to 18 AWG 
magnet wire. Build = thickness of coating

Coating                 What's it made of       Build           DC 
----------              -----------------       -----           breakdown

Thermaleze-T (TZT)      polyester-imide         2.8mils         11kV

Armored Polythemaleze                           3.05mils        11kV
(APTZ)                  modified polyester&
                        modified polyamide-imide

Imideze (ML)            Aromatic polyimide      2.9mils         12kV

Formvar                 modified polyviynyl     3.0mils         10kV
                        formal                  

Sodereze                modified polyurethane   2.9mils         8.5kV

Nyleze                  Polyurethane            2.9mils         8.5kV 
                        & polyamide

* Note: for the dielectric breakdown - These numbers are much bigger than 
for bulk materials because they are very thin coatings. The breakdown 
field increases as the thickness goes down. {a similar effect happens 
in gases and liquids and was studied by Paschen}

Anyway, here's the dielectric constant/DF numbers for these matearials:

Material                Dielectric Const. / DF x 10^-3

                1kHz            100kHz          1Mhz            Rating
TZT             3.7/5.6         3.56/16.4       3.58/21.5       3rd

APTZ            3.86/6.9        3.69/22.1       3.67/26.6       5th

ML              3.34/0.9        3.3/5.7         3.36/9.8        2nd to 
                                                                teflon

Formvar*        3.6/11.2        3.41/25.2       3.37/28.4       5th

Soldereze       3.85/11.3       3.66/20.7       3.66/23.1       4th

Nyleze          4.07/19.7       3.78/27.1       3.75/27.2       6th

* This shows that Formvar is far from an ideal coating for magnet wire
used in Tesla Coils when compared to something like Polyimide coatings

Even the poorer rated commercial wire coatings are acceptable in most 
cases, though higher Q's can be obtained if you use magnet wire coated 
with ML, TZT, or Soldereze. Formvar coated wire in various builds is 
frequently found surplus on bulk rolls and is cheap by the pound, so 
don't feel bad if you end up using it.

Richard Quick 

... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12