The incision of the glass can be performed with the use of the grindstone or with acidofluoridrico. For the incision to the grindstone it is essential to know how to draw and to recognize the most proper wheel for the job to be performed (stone to the corindone, it grinds diamantata). The cut must be homogeneous and you/he/she must not introduce depth diseguali. For the incision with sour fluoridrico is necessary to observe some precautions, from the moment that you/he/she can provoke scorches and poisonings: it needs therefore to endow him of gloves in rubber, mask and glasses to protect from the vapors. The environment of job must sufficiently be airy. It is essential to dilute the sour fluoridrico with water to get incisions more clear.