Question to top luthiers: “What percentage of damage to … · 2020. 3. 27. · Question to top...
Transcript of Question to top luthiers: “What percentage of damage to … · 2020. 3. 27. · Question to top...
Questiontotopluthiers:“Whatpercentageofdamagetoinstrumentsiscausedbyhumidity?”
Answer:“Allofit,exceptfordomesticviolence”
Thereisnothingmoreimportanttothecareofafinewoodeninstrumentthanmaintainingaconstant45-50%relativehumidityatroomtemperature.Dependingontheinstrumentbuilder,youwillfindallofthemrecommendahumiditylevelinthatrange,butgoingbelow40%orabove60%attypicalroomtemperatureswillstarttocausedamage.Mostmanufacturersdonotcoverdamagecausedbyhumidityintheirwarranties.
Whiletoomuchhumiditycancausedamage,mostdamageoccursbytheinstrumentsdryingoutduringwintermonthswithverylowrelativehumiditylevels.Coldairholdsmuchlessmoisturethanwarmair,soeveniftheweathermantellsyouthatit’s100%humiditywhenit’s15degreesoutside,that’saboutthesameamountofhumiditysuspendedintheairas5%relativehumidityat70degrees.
Howdoesthelowhumidityimpactinstruments?Woodshrinksmuchmoreacrossthegrainofthewoodthanalongthelengthofthegrain.Asthehumiditylevelsdrop,thetopoftheinstrumentwillshrink,andwillstarttoslightlysinkintothebody.Thiswillcausebracingintheinstrumenttocomeloose,andoftencausesasplitintheseaminthecenterofthetopasshownbelow:
Cracksmayalsooccuronthebackorsidesoftheinstrument.Theverybestinstrumentsarelightlybuilttoimprovesound,soifyourinstrumentisparticularlywellmade,itismorelikelytosustainhumiditydamagethanthemorecommonfactory-madeinstruments.
Whydoesaninstrumentneedhumidity?Freshcutwoodisfullofwater.About72%ofthemoisturecontentoffreshcutwoodissap,andtheremaining28%issaturatedinthefibersofthetree.Beforebuildingwithwood,it’sairdriedforatleastayear,andusuallydriedinakilnaswell.Moisturecontentofthisdriedwoodisbetweenfourandelevenpercent.Woodisnevercompletely“driedout”itretainsmoisturecontentof4-11%dependingontheambienthumidity.Woodwilltypicallygainorlose1%forevery5%changeinrelativehumidityintheambientair.
Woodexpandsandcontractsasthemoisturecontentchanges.Whatmakesthisaparticularprobleminawoodenmusicalinstrumentisthatthewooddoesn’texpandandcontractevenly.Woodexpandsandcontractsacrossthegrainat4-8%dependingontheanglethatthewoodwassawn,andthewoodspecies.Itexpandsandcontractsalongthelengthofthegrainabout.01%(almostnoexpansionorcontractionatall).
Inadditiontoloosebracesandcracks,youmaynoticethatfretwireswillprotrudepasttheneckinwinterbecausetheneckwoodwillshrink.You’llfeelthesharpedgesofthefretswhenyourunyourhanddowntheneck.Donotmakethemistakeoffilingdownthefretwire,asthey’llbetooshortwhentheneckre-hydrates.
HowdoImeasuremyhumidity?You’llwanttoknowwhatthehumidityisinyourhome.Therearealotofsmallinexpensivehumidistatsonthemarketthatrangefrom$3-$25.Theyarefrequentlyinaccurate,butthey’llatleastgetyouintheballpark.Youmaywanttobuyseveraldifferentbrandsandtakeanaverageofthereadings.Calibratedhumidistatsareavailableandaremoreaccurate,butarequiteabitmoreexpensive.Beingoffbyafewpercentwhenhumidifyinganinstrumentisnotaproblem.Ifyou’reinthe45-50%range,you’llbefine.
Whataremyoptionsforhumidifyingmyinstruments?Thereareanumberofoptionsandawiderangeofpricepointsforhumidifyingyourinstruments.Themainvariablesarethecostofthehumidificationequipmentandhowfrequentlyyou’llneedtotakeactiontokeepitstableatthedesired45-50%relativehumidity.Factorstoconsiderare:
• Wheredoyoulive?Ifyou’reinalocationthatrarelygetsveryhotorcoldyoumaynotneedtodomuch.Youcanfindsomehumidityhistoryforyourlocationathttp://www.shorstmeyer.com/wxfaqs/humidity/rh.html
• Howmanyinstrumentsdoyouhave?Ifyouonlyhaveafew,anddon’tdoalotoftraveling,youmaybefinewithaninexpensivesoundholetypehumidifier.
• Doyouwanttocombinedisplayoreasyinstrumentaccessaspartofyourhumidificationsolution?Thereareseveralmanufacturersthatbuildhumidifieddisplaycabinetsthatcombinehumiditymanagementwithdisplay,easyaccesstoinstrumentsandsecuritymeasures.
Sound-holehumidificationistheleastexpensiveandmostcommonwayofhumidifyinganinstrument.Asmallspongeisenclosedinaplasticcontainerthatfitsinthesoundholeoftheinstrument.Theinstrumentthenisstoredinitscase,Aconcernisthatthespongemaydryoutveryquickly,andyoumayendupwithnohumidityinthecase.Monitoringthehumidityleveliscritical.Youmustalsobeverycarefulnottodripwaterinsidetheinstrument.Itisaneasysolutionforasmallnumberofinstruments,butyouneedtocheckeachcaseeveryfewdays.It’salsoagoodideatoputasmallinexpensivehumidistatineachcasetoseewhatthehumiditylevelis.
Chemicalhumidificationisacommonupgradefromwaterbasedsoundholehumidification.Itreplacesthespongewithachemicalpackthatmaintainsapre-determinedhumiditylevel.Youneedtostoretheinstrumentwiththechemicalpackintheinstrumentcase,oryoumayoptforasingleinstrumentdisplaycasecombinedwithachemicalpack.Thepackslastmuchlongerthanasponge,butdoneedtobereplacedeveryonetothreemonthsdependingonyourambienthumidityandhowmuchhumidityleaksoutoftheenclosureyouarekeepingtheinstrumentin.Thechemicalpacksarefairlycosteffectiveforoneortwoinstruments,butifyou’retryingtohumidifymoreinstruments,dozensofhumiditypackseverymonthortwostartstoadduptoalotofmoney.
Roomhumidifiersareapopularsolutionforanyonewithalargenumberofinstruments.Forapproximately$100youcangetanevaporativehumidifierthatwillkeeparoomat45%relativehumidity.Thebestonesarecontrolledbyadigitalhumidistatthatturnsthemonasneededtomaintainadesiredhumiditylevel.Unfortunatelydrywallusedinmosthomesdoesnotholdmoisturein.Atypicalroomwillrequiretwotofourgallonsofwateraday.Themoisturemaybecometrappedinwallinsulationandcausemold.Ifyou’reusingaroomhumidifier,youmaywanttolookatyourmoisturebarrierfortheroom,andlinetheroomwithcedar.
Wholehousehumidifiersareavailable,butgenerallyarenotdesignedtomaintainhumidityof45%ormoreincoldclimates.They’reintendedtomakehumanscomfortableatabout30%RH.Systemsareavailablethatwillmaintain45%relativehumidity,butaregenerallydesignedforcommercialapplicationsandaremuchmoreexpensive.
Humidifieddisplaycabinetsareavailabletoholdsingleormultipleguitarswithbuiltinevaporativehumidifiers.Somearealsoavailablewithdehumidifiers.They’redesignedtokeepyourinstrumentsat45%relativehumidity,andineasyreachtotakeoutandplay.Theyofferexcellentutility,butareexpensive.
Here’sasummaryoftheoptions,withprosandcons:
Whateveroptionfitsyourlifestyle,instrumentcollectionandbudget,keepingyourinstrumentsproperlyhumidifiedwillkeepthemplayingandsoundinggreat,aswellasprotectingyourinvestment.Ignoringhumiditywillalmostcertainlyguaranteedamage.