Works of commercial and fine art are often engraved or etched upon some relatively hard surfaced material such as wood, glass, tile, slate, other ceramic, or even sheets of various kinds of metal. It is known to make abrasive transfers by means of stencils onto these work substrates or media by using one or more jets of some abrasive material in compressed air. Commonly a fine sandblasting grade of sand is used to make the abrasive etching or engraving.
Many stenciling systems have been devised to mask, or partially mask, the work substrate or medium upon which the etching or engraving is to be transferred. Typically this involves the cutting of a stencil from some softer material which is relatively more abrasion resistant than the work substrate on which the engraving is to be transferred. One problem with some known stencil and engraving methods is that the stencil is very soon worn out by the abrasive process after only a few engraving and etching transfers have been made. This typically requires that a number of stencils be cut, if many transfers are expected to be made. This both increases the cost of the transfer process for multiple copies, and tends to limit the process to the use of abrasive transfers for art work which does not have a great deal of detail. It is surmised that the reason for this is that cutting multiple copies of stencils with much fine detail is simply too time consuming a process to be commercially feasible.
One approach to this problem is presented by a polyurethane sandblasting stencil manufactured by the 3M Company, and further described in U.S. Pat. No. 3,916,050. However, the 3M product is adhesive backed and is suitable only for one time use. This stencil does not meet the need for a durable reusable stencil in an abrasive etching system.
Methods of attaching other stencils to the work substrate or work medium, such as double sided tapes of various kinds, are unsatisfactory, both because they allow abrasive fuzzing of edges and details by virtue of the fact that the abrasive carrying medium, typically compressed air, forces the abrasive under the untaped portions of the stencil, and also because of problems in getting the adhesive of the tape off of the work medium after the abrasive engraving transfer has been completed.
What is needed then is a stenciling process for abrasive engraving transfer of fine and commercial art work containing a large proportion of detail. This stenciling process should be at once capable of being held closely to the surface of the work medium to avoid abrasive fuzzing of detail, and at the same time be highly resistant to the abrasive process itself so that it may be reused, and thereby justify the time expenditure of cutting a stencil with so much fine detail.
USPTO Backgrounds
USPTO Backgrounds