by “ readable ” is meant that the identification indicia can be read by the intended method , i . e ., human readable or machine - readable . by “ identification indicia ” is meant information about the part including , for example , manufacturing date , drawing number , part number , manufacturing location , manufacturer , site assembly location , etc . by “ resistant to dip galvanizing ” is meant that the tag stays attached to the part and survives all of the galvanizing steps and is intact to an extent that the identification indicia can be read . by “ dip galvanizing ” is mean the application of a molten zinc - based coating to a part to cover designated surfaces of the part . by “ pre - galvanizing treatment ” is mean alkali dipping , acid dipping , flux dipping , and / or any other treatment of part to make is suitable and ready for dip galvanizing . by “ resistant to pre - galvanizing treatment ” is meant that the temporary coating stays intact during the pre - galvanizing treatment to such an extent that the underlying identification indicia remain readable . by “ without obscuring readability ” is meant that the identification indicia remain readable . a tag bearing readable identification indicia is disclosed in u . s . pat . no . 5 , 855 , 969 . the tag preferably is metal , although ceramic and other exotic materials are possible . cost considerations , however , currently make metal ( e . g ., a ferrous metal such as steel ) the material of choice for the tag . such a tag can withstand molten zinc , because molten zinc does not “ wet ” the tag &# 39 ; s siloxone coated surface . the &# 39 ; 969 patent employs a layer of coating containing silicone resin having pendant groups selected from one or more of methyl groups and phenyl groups , and a white ( e . g ., opacifying ) pigment ( e , g ., tio 2 and / or tio 2 coated mica ). the layer has been cured to a degree effective for marking by blackening of the layer by a laser beam . other tag coatings resistant to pre - galvanizing treatment can be used as is necessary , desirable , or convenient . the coatings of choice , then , are silicone or siloxone resin coatings , such as described in “ silicone resin emulsions for high - temperature coatings ”, modern paint and coatings , september 1993 , argus , inc ., atlanta , ga . ( 1993 ). silicone resin binders typically are heat - cured in the presence of catalysts with typical catalysts being selected from acids , bases , and the salts of metals , for example , zinc , tin , lead , or chromium octoates . silicone resins can be blended or chemically combined with other film - forming polymers provided that the ultimate cured phenyl - substituted silicone binder is stable at the hot metal temperatures of use of the inventive labels . phenyl - substituted resins are well known in the art , such as represented by d . h . solomon , the chemistry of organic film formers , second edition , robert e . krieger publishing , inc ., pp 334 et seq . ( 1977 ). the disclosures of the cited references are expressly incorporated herein by reference . the inventive marking scheme desirably employs a composition , which is darkenable ( e . g ., blackened ) by the focused co 2 or other laser energy . because many of the applications of this technology may involve the imaging of bar codes ( red light absorptive or “ black ” bars on a white background ), the composition should be highly reflective to the red light commonly used to scan such bar codes . white or red coatings , then , are preferred . for human readable characters ( e . g ., one or more of alphanumeric characters or graphics ), white backgrounds are preferred . after coating , the tag now is ready to be marked by the energy of a focused laser beam emitted from a laser . a co 2 laser is preferred for its cost effectiveness and ruggedness in industrial environments . other lasers , however , can be used at the expense of cost and risk of eye damage in industrial environments . marking of the tag preferably is accomplished in accordance with the raster - scanning technique disclosed in u . s . pat . no . 5 , 855 , 969 . in accordance with this technique , the tags move in the x - axis direction past a raster - scanning infrared laser beam emitting co 2 laser that raster - scans in the y - axis for forming the indicia on the tags . scanning the laser beam through the use of two galvanometers ( so - called x / y scanning ) and a flat field focusing lens also is a preferred marking method . a temporary film then is applied over the marked ( imaged ) tag surface after marking . this assures that the film is void free ( not affected by the laser marking process ). the temporary film is resistant to pre - galvanizing treatment . such film can be applied wet and dried ( cured ) or can be applied as a free - standing film optionally with an adhesive . acrylic , vinyl , and synthetic rubber adhesives are common . any technique whereby the film can be applied and remain in place during the pre - galvanizing treatment is acceptable for purposes of the present invention . suitable materials include , for example , acetate films , acrylic films , vinyl films , polyethylene films , polypropylene films , and the like . testing has revealed that polypropylene films with synthetic rubber adhesives provide good chemical resistance through the pre - galvanizing treatments and burn away cleanly during the molten metal dip . an instructive adhesive backed film applicator is shown in fig1 . the metal tag , 1 , has been coated at least on one side , 2 , with a cured siloxone coating and has been previously laser marked with man readable characters , 3 , and bar code indicia , 4 . a finger guard guide , 5 , guides the entry of tag 1 and contains a sensor , 6 , which detects the insertion of a new tag , such as tag 1 . upon such detection , powered laminating rollers , 7 and 8 , are rotated in the direction shown by the arrows to draw in and laminate tag 1 with an adhesive film , 8 , and optional adhesive backed film , 9 . the adhesives film sides 8 a and optionally 9 a are bonded to the tag surfaces , e . g ., side or surface 2 . film 8 protects surface 2 , characters 3 , and indicia 4 from the galvanizing caustic , acidic , and flux pre - treatments , and optional film 9 similarly protects the tag &# 39 ; s unmarked surface . another pair of rollers , 10 and 11 , are rotated in the direction shown by the arrows with a limited torque drive ( details not shown ). once the leading edge of tag 1 is sensed by a second sensor , 12 , in a lower guide , 13 , and the top edge of tag 1 is located at position 17 , a heated wire , 15 , is extended by an actuator , 16 , from a first position , 15 a , to a second position , 15 b , whereby film 8 and option film 9 is cut and tension rolls , 10 and 11 , proceed to draw tag 1 toward an exit , 18 . [ 0030 ] fig2 depicts a completed inventive tag , 22 , which is preferably tape protected on both sides so that the areas shown as 19 and 20 are excess tape bonded together so as to prevent exposure of any bare adhesive , thereby making the inventive tag easy to handle . an optional hole , 21 , is used to facilitate wire attachment of tag 1 to a part for its identification , which is to be pretreated and galvanized . the attaching wire is simply pushed through hole 21 and the protective film ( s ). the tag can be affixed to the part to be dip galvanized by a variety of techniques either before or after being coated and / or laser marked . in this regard , the tag can be welded ( e . g ., spot welded ) onto the part , attached with a wire ( as facilitated by hole 21 in fig2 ), or by any other technique at hand . pre - galvanizing treatment of the part typically involves an alkali dip ( e . g ., 180 ° f . with 10 % naoh for 45 minutes ), followed by an acid dip ( e . g ., 155 ° f . with 14 % h 2 so 4 for 30 minutes ), followed by flux dipping ( e . g ., zinc chloride / ammonium chloride solution for 30 seconds ). it will be appreciated that a variety of additional alkali &# 39 ; s can be used , such as , for example , alkali metal hydroxides , oxides , and the like . strong bases ( e . g ., oxides , alkoxides , and the like ) based on other than alkali metals also can be used at the risk of increasing costs . the same is true for the acid dip as other mineral and organic acids can be used . the flux dipping also can employ additional fluxes , as those skilled in the art will appreciate . galvanizing operations as commercially practiced employ a molten zinc or zinc - based bath held at elevated temperature ( e . g ., ˜ 850 ° f .). the part with attached tag is immersed or dipped into the molten zinc bath for a time sufficient for the exterior or exposed surfaces of the part to be coated with zinc ( say , around 12 minutes ). thereafter , the part is removed from the bath and the zinc coating permitted to cool . the pre - treatment protective film will be burned and / or melted in the zinc bath to expose the imaged identification indicia , which are resistant to the zinc bath in terms of the readability of the identification indicia , i . e ., without obscuring readability of the identification indicia . while the invention has been described with reference to a preferred embodiment , those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention . in addition , many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof . therefore , it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention , but that the invention will include all embodiments falling within the scope of the appended claims . in this application all units are in the metric system and all amounts and percentages are by weight , unless otherwise expressly indicated . also , all citations referred herein are expressly incorporated herein by reference .