Download Bipolar Tesla Coils

BipolarTeslaCoils:
Experimenter’sGuide
K.R.Scott
Copyright2016
PREFACE
Thistextisnotmeanttobeadetailedengineeringdocumentonhighvoltagedevices.Itis
writtenfor
educationalandinformationalpurposesonly.Thereisnohighlevelmath,theoryor
analysis.Thecontentsareacollectionofempiricalexperiencefrommakinghighvoltage
equipmentovertheyears.Thereisanenormousamountofinformationonlineandin
booksforthosewhowantthereallytechnicalstuff.Whenbuildingthesedevices,youcan
onlycalculateenoughdetailtogetyouintotheballpark,andthenitisalittletrialand
error,goodengineeringpractice,testing,fixingandre-testing.Thisisnotanindepth
study;itisbasicnutsandbolts.Iamaretired(semi-retired)engineer,andforme,itis
aboutthe”funfactor”,solet’sletourcuriositygowild,havesomefunandbesafe.
Regards,K.R.Scott
HighVoltageExperimenterSeries
Willow-TechPublishing
©Copyright2016K.R.Scott
©Copyright2016Allrightsreserved.Nopartofthispublicationmaybereproduced,
storedinaretrievalsystem,ortransmittedinanyform,orbyanymeans,electronic,
mechanical,photocopied,recorded,orotherwise,withoutthepriorwrittenpermissionof
thecopyrightowner.
DISCLAIMER
Theauthorandpublisherhavemadereasonableefforttopresentthisinformationasclear,
conciseandaccurateaspossible.However,theycannotbeheldresponsiblefortheuseor
miss-useofthismaterial.Wearenotliableforanydamagesincluding(butnotlimitedto)
personalinjury,propertydamageorlegaldisputesarisingfromtheuseof
informationcontainedinthisbook.
DONOTUSETESLACOILSAROUNDPACEMAKERS,INSULIN
PUMPS,ORHEARINGAIDS.
BipolarTeslaCoilsoldbyCENCO1920s
IpurchasedthiscoilonEbay.
Withtheexceptionofcleaning,itisinverygoodshape.IusedtheTeslaCADprogramto
calculatethecapacitorvalue,Iwiredituptoasparkgapanda9kV/30maneon
transformeranditworkedgreatafter95years!Mainproblemwasdustonthecoilwhich
cameoffwithapaintbrush.Dustonasecondarycoilwillreduceoutput.Theresidual
electrostaticchargeonthesecondaryattractsdust.
CencoBipolarTeslaCoil
BipolarTeslacoiloperatein½wavemodewhereasthetypicalverticalconfiguredcoils
withthebottomendofthecoilgrounded,operateinthe¼wavemode.The¼WaveTesla
Coilhasthesecondarycoilgroundedandisslightlymoresensitivetotuningandcoupling
thanaBipolarTeslaCoil.OnBipolarCoilsthecouplingisinthecenterareaofthe
secondarywithlessproblemofracingsparkstypicallycausedbytootightcouplinginthe
¼wavecoiland/orinsulationbreakdown.A¼wavecoilcanbemoredangerousasin
someconfigurations,ifthereisashort,oraconductivespark(racingsparks)60Hz
currentcanbecarriedonthesecondary’shighfrequencycurrent(lessisolationbetween
primaryandsecondary).Thereisoneincidentinthe1910s,whenthishappenedtoastage
performerandhewaselectrocuted.ABipolarTeslacoilsomewhatactslikeanisolation
transformerasthesecondaryisnotgroundedandisinsulatedfromtheprimarycoil.The
bipolarTeslaCoilwillgivebetterperformancethanthe¼wavecoilandthedischarges
aremoreimpressive.YoucanforcetheBipolarCoiltooperateinthe¼wavemodeby
groundingoneend.AdescriptionofaHVdischargewandfordrawingsparksinthis
configurationisinthelastsectionofthisbook.
Fig.BisthecircuitthatIprefer,asthesparkgapactsasbothanoperatingsparkgapand
asasafetygap.Thecapacitorseeemstorunalittlecoolerandislesslikelytofail.One
thingthatcanbedone,especiallywithdoorknobtypeceramiccapacitors,istoadda
coupleoffenderwashersseperatedbyanutoneachendofthecaptoactasaheatsink.
Capacitorscanalsobepottedinparaffinforextrainsulationandtheparaffinabsorbsalot
ofheatbeforeitwillmeltandactsasaheatsink.Youcanalsotrydifferentcombinations
ofparaffinandcanolaoil.Beeswaxworksverywell.Manyoftheoldhighvoltagecoils
anddeviceswhereinsulatedusingamixtureofbeeswaxandrosin.Beeswaxandlinseed
oilwillmakeakindofselfhealinginsulationgel.Tryvarousmixturesmeltedtogetherto
gettheconsistancyyouwant.CanolaoilisusedasabaseingrediantforsomeHV
insulatingoils.Itisoneofthenon-toxicreplacementforPCBs.(Polychlorinated
Biphenyls)Verytoxicandisstillfoundinoldtransformers,especiallypolepigsandoil
filledcapacitorsbuiltbefore1979.
OneofTesla’sexperimentalcoilsetups.
G–Electricalpowersource
P–PrimaryDriveTransformer
S–SecondaryDriveTransformer
A,B–SparkGapElectrodes
M–Sheetmicaconfiguredclosetoelectrodestopromoteairflow.
C,C–LeydenJars(Selectedforequalcapacitancevalue”
a,b-Sparkgapcloselyadjusted.
K,K-HighVoltage/HighFrequencysecondarycoiloutput.
ThisisaschematicofElihuThomson’s(1853-1937)DisruptiveDischargeCoilbasedon
Tesla’spatent#454,662.Drivetransformer:15-20kV.Compressedairquenchedspark
gap.Primary:15-20turnsheavycopperwire.Secondary:150turnsfinewireiswoundon
aglasscylinder.Thecoilswhereemergedinatankofboiledlinseedoil.Thiscoil
produced150kV.SomeofThomson’slatercoilsproducedsparksover60incheslong.
SPARKGAPS
Asparkgapwillarcinsteadofsparkingifthecurrentgoingthroughit,istohighi.e.using
aMOT(MicrowaveOvenTransformer–typically2,500volt@500maor5,000voltsDC
(whenusingthediodeandcapacitorvoltagemultiplierthatwasinthemicrowaveoven.A
PoleLinetransformers(PolePig)wiredbackwardswillincinerateasmallorpoorlymade
sparkgaps.IfyouaregoingtousethismuchenergytodrivetheTeslacoilyouneedtouse
arotarysparkgapormulti-gap.Inthiscase,theelectrodesneedtobetungstenandair
cooled.Note:Thesetypesoftransformersaremoredangerousthanneonsignoroil
ignitiontransformers.Whenanaccidentalcontactoccurs,thereisaveryhighprobability
ofelectrocutionorattheleaseverybadburns.Otherhazardswithsparkgapsare
acoustic/electricalnoise,hardUVlight,shockhazards,fireandtheproductionoflarge
quantitiesofOzoneandNitrogenOxides.Ozonehasaverypungentsmell.Youneedgood
ventilationandoutsideair.
SOMEGENERALOBSERVATIONSABOUTSPARKGAPS
Multi-gapsarebetterthanasinglegap.
Rotarygapsarethebestperforminggaps.
Gapelectrodematerialsandgeometryeffectperformance.
Bestelectrodematerialistungsten.Thoriatedtungstenandspotweldingelectrodesaless
expensive.
SparkGapsneedtobecooled.
Airblastquenchingworkswellandifdrynitrogenisused,theyworkevenbetter.
Youcanquenchasparkgapwithstrongrareearthmagnets.N–Spolesacrossthespark.
SparkGapscontinuallyburnopen(widergap)andwillneedtobeadjusted
NeveradjustSparkGapwithpowerplugpluggedinandnevertrustaswitchtobeoffas
theycanshortinternally.
Alwaysdischargethetankcapacitor–leavegroundstraponasthecapscanregeneratea
charge!
Donotstareatthegapinoperation–hardUVcanburnretina(weldersburn–fellslike
sandinyoureyeswherethereisnone).
Asinglestaticparkgapneedstobeadjustedaswideaspossiblebutstillworkreliably.
Seriesgapsareadjustedclosertogether.
SAFETY
ThebestTeslaCoilsafetywrite-uponlinehasbeencreatedbyseveralcoilersandis
availableasanhtmdocumentat:
http://www.pupman.com/safety.htm
“pupman.com”isagreatsiteforinformationandhasbeeninusefromtheearlydaysof
theinternet.
Youcansignupat:
http://[email protected]
Therearehundredsofcoilersthatcontributetothissite.Lotsofstufffromthereallygreat
coilers.
Someofthegeneralsafetyissuesareasfollows:
Electrocutionhazard,especiallyfromthehighthevoltagedrivecircuit,sparkgap,primary
coil.
Alsobeawarethatifthereisashortorgroundfaultthatthethelowerfrequency60Hz
currentcanbecarriedthroughthesecondarycoilalongwiththehighfrequencyhigh
voltagecurrent.TherewasastageperformerthatdidanactwithalargeTeslacoilthat
waselectrocutedintheearly1900sthisway.Thereisalsoonecaseonrecordofasmall
childthatwaselectrocutedfromanunattendedTeslaCoilinthefather’sbasementwork
shop.Nevertrustaswitch,ALWAYSunplugthecoilandputashortingwireacrossthe
capacitor(s).ThedischargesfromthecoilcancauseburnsfromheatandinsomecasesRF
burns.Dischargescancausefirewhencombustiblematerialsarepresentandanexplosion
ifcombustiblefumesareinthearealikeacetone,cleaningsolvents,PVCglue.Ihave
witnessedoneexplosionofaPVCsecondarycoilthatwasputtogetherwithPVCglueand
theresidualvaporswhereignitedinsidethecoilform(voiceofexperience).Thehigh
voltagedischargesfromthesparkgapandcoilterminalwillcreatehardUVlight,ozone
andnitrogenoxides.Theozonewillirritatethethroatandsinusesandthenitrogenoxides
canproducenitricacidwhencombinedwithmoistureinthelungsandcanproduce
chemicallyinducedpneumonia.TheUVlightcanburntheretinaandcause“welders
burn”Properventilationandeyeprotectionisneeded.TheintenseRFradiationproduced
bytheTeslacoilcandamagesensitiveelectronicequipment,especiallyTVremote
controls,cellphone,iPods,etc.
NoisehazardsfromsparkgapandHVdischarges,especiallyrotarysparkgaps.Youcanbe
startledbyashockfromtheelectrostaticchargethatcanremainonsurfaceofsecondary
coil,(especiallyifitisalargecoilwithalotofsurfacearea)aftertheTeslaCoilhasbeen
turnedoff.
DriveTransformer:NeonType9kV/30ma
SecondaryCoilwinding2.4”x10”#26AWG520Turns
PrimaryCoil:3.5”DiameterTunes@11-1/2Turns
Capacitor:2ea1000pF/20kVinparallel=2000pF
DualStaticSparkGap(SteelandBrass)
ThecalculationswheremadeusingTeslaCAD
forthisparticularBipolarTeslaCoilareasfollows:
Createdby:RichardChapman
http://www.richardsplace.net/tesladownload.htm
Note:ThisprogramwillworkwithWindows10
Donotusewirediametersfromcommercialwirecharts.Wind/countturnsfor1inchand
divideby#turnstogetgoodwirediameter.Example:#26AWGis52Turns/inch
dividedintoone=0.01923.Setthespacingbetweenturnsto:“0”.
Calculationsforcapacitorvalueforlinematching.
TeslaMapisanotherpopularCADprogram.
http://www.teslamap.com/download.html
Secondarycoil:2.4”x9”470Turns#26AWG
PrimaryCoil:Tunesat11Turns
Capacitor:2ea.1000pF/20kVTotalCapacitance2000pF
Tested/operatedwith9kV/30maneontransformer.
Baseishardwooddrawerfront.
Theelectrodesaremadefrombrazingrod,threadedwith8-32threadswiththreadedbrass
ballsontheends.Therodswheregroundtoapointwithabeltsanderononeendandthen
threaded.Thiswayyoucanhavepointedorsphericalelectrodes.Thesecondarycoil
supportsarefromendsofanewwoodentoiletpaperdispenser.Thereisashortbrasstube
inadrilledholethatgoestothecoilelectrodeends.
Brazingrodsinavarietyofdiametersaresoldbythepoundatanyweldingsupply.
Thebrassballswherepurchasedfrom:http://www.grandbrass.com/
SecondaryCoil:1.875”x10”#26AWG520Turns
PrimaryCoil:4.5”DiameterTunesat8-1/2Turns
Capacitor:1200pF/20kVCeramic
DriveTransformer:5KV/10maOpenFrameNeon
Baseishardwoodtrayturnedupsidedown
SparkGapBrassandSteelAngle
bracketsandstainlessmachinescrews
SecondaryCoil:1.875”x11”#26AWG
Primary:CoaxCableShieldsbraid&Centerconductorused.
Tunedat:10-1/2Turns
Capacitor:1000pF/25kV-NAVYMica/Ceramic
DriveTransformers:2ea3.5KVWiredfor7kV
LineFilterused(rightsideofunit)
SparkGap:Brassandsteel
Baseisanewhardwoodcuttingboard+4RubberFeet.
SecondaryCoil:1.875”x10”#26AWG
PrimaryCoil:CoaxCableTunesat10Turns
Capacitor:1300pF/18kVCeramicDoorKnobType
Transformer:5kV/10kV/10maOpenFrameNeon
SparkGap:BrassandSteel
Base:HarwoodDrawerFace
4Turnedlegs.
Secondary:2.4”x8”420Turns#26AWG
Primary:#12AWGTunesat:11Turns
Capacitor:1200pF/20KV
DriveTransformer:5kV/10ma
SparkGap:SteelandBrass
Box:Madeinmywoodshop.
SecondaryCoil:2.4”x7.5”#26AWG400Turns
Primary:Tunes@11Turns
Capacitor:2ea690pF/20kVTotalCap=1380pF
SparkGap:SteelandBrasswith12VMuffinFan
Baseissmallfinishedshelf.
Secondary:2.4”x9”#26AWG470Turns
Primary:3.5:ODTunes@11Turns
Capacitors2ea690pF/20kVTotalCap:1380pF
DriveTransformerAutoIgnitionCoil
SparkGapBrassandSteel
Theignitioncoilisdrivenusingalightdimmer
anda2ea1uF/350VMotor“RUN”Capacitors
DONOTUSEMOTORSTARTCAPS!
SecondaryCoil:1.875”x12”#26AWG625Turns
PrimaryCoil:Tunes@10Turns
Capacitor:2000pF/30kV
DriveTransformer:7.5kV/30ma
SparkGapStainlessSteel
RemoteON/OFFSwitch
Base:hardwoodDrawerfrontandturnedlegs
SecondaryCoil:1.875x12”#26AWG625Turns
PrimaryCoil:Tunes@10-1/2Turns
Capacitor:2000pF/30kV
DriveTransformer5.0kV/10maOpenframetype.
SparkGap:Stainlesssteel
BaseisrepurposedwoodKleenexbox.
Secondarysupport:Redoak@T-Paperholderends.
Terminals:Brazingrodand1.2”brassballs.
BipolarTwinTeslaCoilConfiguration
SecondaryCoils:2.4”x8”#26AWG420Turns
Primary:TVCoaxCableTunes@10Turns
Note:Primarycoilsarereversewound.
Capacitor:2ea690pF/20kvTotalCap:1380pF
Base:RepurposedJewelryBox.
SparkGap:Brassandsteel.
TopLoadTerminalsare:Brassdoorknobs.
SecondaryCoil:3.5”x30”#26AWG,1,560Turns.
Primary4.5”DiameterTunes@11-1/2Turns
Capacitor:0.02uF/15kV
SeriesSparkGap4ea.SparkPlugs&12VMuffinFan.
HousingConsoleTable,Reinforcedwithwood.
Variac(autotransformer),ON/OFFToggleSwitch
Drawerknobremoved&replacedwithredjeweledindicatorlamp.
Two5kVDriveTransformersTotal:10kV.
Electrodessolidgauge#10AWG/brassballs/crimpterminals.
Hotmeltglueworkswellforinsulatingwireconnectionsandhardware.
DrillintowoodwithaForstnerdrillbit,usewasherwithscrew.
MusicalBipolarTeslaCoil
RegionalMuseumJohnsonCityTennessee
http://roadsideamerica.com/tip/44988
http://www.pictorialism.com/tesla.html
Locatedin:BigBearLake,CA
HVDischarges
Dischargesthroughclearlightbulb.
Dischargesriseincenterduetoheatedions/air.
1930
KinraideCoil
Early1900s
HerculesTesla-ThomsonElectrotherapyUnit1907
Bipolarcoilsecondaryisgrounded(centerelectrode).
RotarySparkGap.
1915
1918
1930sPopularScience
Gaiffe’sBipolarResonatorusedinelectrotherapyearly1900s.
ManufacturedbyAdolpheGaiffeinParis
1891BipolarTeslaCoilpresentedtoLordKelvinin1897
ThistypeinventedbyNikolaTeslain1891
25Watts@110VDCInput
ElectricalExperimenterJuly,1919
FreeDownloadArchive
http://www.electricalexperimenter.com/
COILWINDING
ThesmallcoilwinderthatIuseisfabricatedfromanoldmechanicalfilmwinder,
threadedrodstock,andtwoplasticfunnels.Itworksverywell.Itisfastandeasyto
control.IgetbettercontrolusingamechanicalcrankthanIdidfromamotorizedwinder.
Afewhintsoncoilwinding.
Wherethincottonglovesand/orwashyourhandsbeforewindingthecoil.Avoid
gettingoilandsaltfromyourhandsonthewire.
Useanew3-4”paintbrushtokeepdustofthecoil.(Especiallybeforecoating)
Sandthecoilformwithfinesandpaperandcleanwithalcoholbeforewinding.No
SteelWool!
Theareawherecoiliswoundneedstobewarm–donotwindcoilincoldwork
shopasthewirewillexpandandloosenthecoilwhenitiswarmedup.
Coatthecoilwithseveralthincoatsofinsulatingspray.Thebest,mostcost
effectivespraythatIhavefoundisRust-OleumCrystalClearEnamel,itisavery
goodinsulatoranditdriesquickly.Thebesttechniqueistohaveafixturewherethe
coilcanbeslowlyrotated–amicrowaveovenmotorworkswell–thiswillreduce
runs.
Donotusedatafromwirechartsfor#ofturns/diameterorwire–handwindand
inchfor#ofturns.Example#26AWGis52Turns/inch,1/52=0/01923Diameter.
Usethis#TeslaCAD.
DischargeWand
Note:Thewireexitsthewandattopforsafety.
MaterialPVCElectricalConduit.
TerryFilterforprotectingdrivertransformerandhomeelectricalsystem
http://www.hvtesla.com/terry.html
ExceptionallywellmadeTerryFiltermadeforalargeTeslaCoil.
http://ian.macky.net/tesla.html
KEEPTHESEDEVICESAWAYFROMCHILDREN,PETSAND
INDIVIDUALSNOTFAMILUREWITHHIGHVOLTAGESAFETY.
IFYOUAREINEXPERIENCEDINWORKINGWITHTHETYPES
OFDEVICESDESCRIBEDINTHISMANUAL,PLEASESEEKHELP
FROMAPERSONWHOKNOWSHOWTOSAFELYWORKWITH
HIGHVOLTAGEDEVICES.PLEASESEETHEWEBLINKSLISTED
ATTHEENDOFTHISMANUALFORADDITIONAL
INFORMATION.
More people are killed each year by low voltage than by high voltages. The most common
electrocutionhazardis110and220voltsAC.Theamountofcurrentthatpassesthroughthebody
determines the physiological damage. If electrical contact is made to a person whose skin
resistanceisloworbysufficientlylargecontactarea,enoughcurrentcanpassthroughthebodyto
causeburns,damagetonerves,musclesordeath.Youcanbecomepartoftheelectricalcircuit,
evenwhenungroundedandstillbeelectrocuted.Highvoltagescanpenetrateinsulationmaterials,
orjumpthrutheairtofindapathtoanunwaryexperimenter’sbody.Itisnotadvisabletowork
alone. Capacitors can hold a lethal charge for several days and can partially recharge due to
dielectric retention after discharging and shock the experimenter. Electrolytic capacitors can
explode violently if the voltage rating is exceeded;AC current is applied (shorted rectifier) or
hooked up backwards. Capacitors that are discharged through low resistance load such as low
resistance,wires(smalldiameterwire,coilsresisters,etc.)cancauseanexplosionandsprayhot
metal and sparks. High voltage can cause fires and/or explosions if combustible vapors are
present.Electricaldischargesunderfluidssuchasoilcancausethefluidtoexpandwithexplosive
force. Discharges in a vacuum can produce X-rays under some circumstances. Ozone (O3) is
producedinelectricaldischargesandcanreachtoxiclevelsifventilationisnotadequate.Beaware
thatTesla,OdinCoilsandsparksgapsproduceelectricalinterferencewithTVandradios.You
need to shield both the power line feed and airwaves from this. Use RF line filtering and a
groundedFaradaycage.
CHECKOUT:http://pupman.com/safety.htm
See:“Skineffect”onwebsite:http://en.wikipedia.org/wiki//Teslacoil
TESLACOILDESIGNBOOKS
TheUltimateTeslaCoilDesignandConstructionGuidebyMitchTilbury2007
UnderstandingTeslaCoilsandBeyondbyBrentTurner2013
DRSSTC:BuildingtheModernDayTeslaCoilbyDanielMcCauly2006
TheTeslaHighFrequencyCoil:It’sConstructionandUses1912
VintageTeslaCoilandHighVoltageBooks-GreatInfo…
ThesebooksareavailableasFREEdownloadsinpdfformatfrom:
https://books.google.com/
https://archive.org/details/googlebooks
https://www.gutenberg.org/
https://openlibrary.org/books
TheInventionsandwritingsofNikolaTeslabyThomasCommerfordMartin504
Pages1894
TheTeslaHighFrequencyCoil:ItsConstructionandUsesbyGeorgeF.Huller160
Pages1910
CurrentsofHighPotentialofHighandOtherFrequenciesbyWilliamBenham
Snow,M.D.302Pages1911
HighFrequencyApparatus,Design:ConstructionandPracticalApplicationby
ThomasStanleyCurtis269Pages1920
ExperimentalHighFrequencyApparatus:ConstructionofInductionCoilsand
TransformersbyThomasStanleyCurtis269Pages1920
High-FrequencyCurrentsbyFredrickFinchStrongM.D.301Pages183
Illustrations1908
HighVoltagePhysicsbyL.Jacob,M.Sc.105Pages1930s
TheInductionCoilinPracticalWorkIncludingRoentgenXRaysbyLewisWright
192Pages1897
TheInductoriumorInductionCoilsbyHenryNoad,Ph.D.135Pages
RuhmkorffInductionCoils:ThereConstruction,OperationandApplicationwith
ChaptersonTeslaCoil,InductionCoilsandRoentgenRadiographybyH.S.Norrie
208Pages1896
OldMagazinesources
https://archive.org/details/magazine_rack?sort=titleSorter
https://en.wikipedia.org/wiki/List_of_online_magazines
http://www.electricalexperimenter.com/
http://www.americanradiohistory.com/Electrical-Experimenter.htm
http://www.americanradiohistory.com/Popular-Electronics-Guide.htm
http://www.popsci.com/archives
https://books.google.com/books/about/Popular_Mechanics.html?
id=49gDAAAAMBAJ
https://archive.org/details/TheAmateurScientist
http://www.electrotherapymuseum.com/Oneoftheverybestsources
ofinfo,photographs,videosandhistoricalstuffonhighvoltage
devices.
Projectsplans
http://www.teslastuff.com/
http://www.amazing1.com/
http://www.instructables.com/
http://makezine.com/
LinkstoBipolarCoilProjects
http://www.electrotherapymuseum.com/
http://tesla-coil-builder.com/double_cone_bipolar_tesla_coil.htm
http://lateralscience.blogspot.co.uk/2012/07/main-page.html
http://ydjj.blogspot.com/2011/10/my-bipolar-tesla-coil.html
http://www.teslasociety.com/teslacoil.htm
http://thehappyheathen.com/?p=50
http://thehappyheathen.com/?tag=tesla-coils
https://www.museumofdiscovery.org/experience/world-record-musical-bi-polar-teslacoil
http://teslaweb.freeservers.com/tesla1.htm
http://www.roadsideamerica.com/tip/44988
http://tesla-coil-builder.com/FlatSpiralSecondaryLongitudinal.htm
http://tesladownunder.com/Tesla_coils_intro.htm
http://www.lateralscience.co.uk/tesla/index.html
http://kenscoil.com/tesla-coils/
PARTS
http://www.amazing1.com/tesla-coils.html
http://www.easternvoltageresearch.com/faq.html
http://www.teslastuff.com/
http://www.grandbrass.com/
http://prosites-llcwccd.homestead.com/