Xyoo 1932, thawj daim ntawv siv quav ciab-coated ob-daim ntawv khob tuaj. Nws lub ntsej muag du tuaj yeem luam tawm nrog ntau cov qauv zoo nkauj los txhim kho cov txiaj ntsig kev txhawb nqa. Waxing daim ntawv khob, ntawm ib sab, tuaj yeem zam kev sib cuag ncaj qha ntawm cov dej haus thiab daim ntawv, thiab tuaj yeem tiv thaiv cov nplaum ntawm cov kua nplaum thiab txhim khu kev ua haujlwm ntawm lub khob ntawv; ntawm qhov tod tes, nws kuj nce lub thickness ntawm sab phab ntsa, uas zoo heev txhim kho lub zog ntawm daim ntawv khob, yog li txo tus nqi ntawm daim ntawv tsim nyog los ua kom muaj zog daim ntawv khob txo nqi ntau lawm.
Raws li waxed ntawv khob ua ntim rau cov dej txias, tib neeg kuj cia siab tias yuav siv lub thawv yooj yim los tuav cov dej kub. Txawm li cas los xij, cov dej kub kub yuav yaj cov wax txheej nyob rau sab hauv ntawm lub khob ntawv, thiab cov kua nplaum qhib yuav sib cais. Yog li ntawd, cov ntaub ntawv siv quav ciab-coated daim ntawv khob tsis haum rau tuav cov dej kub.