| Vulcanized Rubber Stamps | | | | finished stamp die. Lasers are controlled directly |
| The traditional red rubber stamp that everybody | | | | from a computer, the software drivers supplied |
| is familiar with will have been manufactured in a | | | | with lasers work with many graphic programs |
| vulcanizing press. The first rubber stamp | | | | such as CorelDraw. |
| vulcanizing press was patented in 1890 by Charles | | | | Approximate cost of a 25 watt Laser suitable for |
| Schultze in New Orleans USA. Vulcanizing is today | | | | stamp making is $40,000 |
| one of the most cost effective methods of | | | | Advantages - Production is computer controlled, |
| making rubber stamps for mass produced | | | | custom made stamps can be made easily |
| stamps. Each batch of stamps is produced using a | | | | Disadvantages - High capital investment, |
| mould. This method of manufacture is more | | | | maintenance costs and running will be much higher |
| suited to stamp making where the same moulds | | | | than vulcanizing or polymer methods of |
| are used over and over again. Making custom | | | | manufacture. |
| made stamps with a vulcanizing press requiring | | | | Liquid Polymer Rubber Stamps |
| 'once only' moulds will drive the cost of | | | | Converting rubber stamp polymer from a liquid |
| manufacture up significantly. | | | | into a solid to make stamps is quite fascinating. |
| Making the mould - before a mould can be made | | | | Polymer stamps are manufactured between two |
| you must have a master plate manufactured | | | | sheets of glass using precision controlled UV light |
| from metal or polymer, the master plate has the | | | | which passes through a negative containing the |
| necessary relief (the artwork is raised) to make | | | | stamp artwork solidifying the polymer. Negative |
| an impression in the mould. Having a master plate | | | | production has been simplified with the introduction |
| made each time a mould is required is what | | | | of water based negative technology, photographic |
| drives up the cost of manufacture for vulcanized | | | | chemicals for producing negatives are now a thing |
| stamps. Pressing the master plate into a Matrix | | | | of the past. |
| board creates the mould that will accept the | | | | The first step in making polymer rubber stamps is |
| rubber. Heat and pressure is applied to the master | | | | to print your images, clipart or text onto Vellum, |
| plate and matrix board inside a Vulcanizing press. | | | | an almost transparent paper like film. |
| The Matrix follows the shape of the relief | | | | To produce quality stamp artwork you must use |
| provided by the master plate, this then hardens | | | | a laser printer, inks from bubble jet printers are |
| on cooling. | | | | translucent allowing UV light to pass where it |
| Making Rubber Stamps - Creating stamps is a | | | | should not. Water based negatives are easily |
| simple process once the mould is made. Raw | | | | washed out after being exposed for a few |
| rubber stamp gum is placed on top of the mould | | | | minutes in a UV exposure stamp machine. |
| and then placed inside the stamp press. Hydraulic | | | | Polymer contained in a sachet is now replacing the |
| pressure is placed upon the rubber and the mould | | | | older cumbersome method of using foam tape to |
| from within the stamp press causing the rubber | | | | create a dam and pouring of rubber stamp |
| to melt into the areas of the mould that contain | | | | polymers, the sachets have also addressed the |
| the images and text, curing and hardening takes | | | | age old problem of removing air bubbles from the |
| about 10 minutes. Once cured the sheet of rubber | | | | poured polymer. |
| is pulled away from the mould and cut up into | | | | The negative of your artwork and polymer |
| individual stamps to be affixed to mounts. | | | | sachet is sandwiched between two sheets of |
| Cost of a vulcanizing system is approximately | | | | glass spaced 2-3mm apart which is then exposed |
| $12,000 AUD | | | | in the machine for a few minutes. Once you have |
| Advantages - Low cost of production for mass | | | | completed the exposure it is a simple process of |
| produced stamps, good ink transfer. | | | | cutting open the sachet and washing away the |
| Disadvantages - Cost of producing master plates | | | | excess unexposed polymer before returning the |
| and moulds for custom made stamps. | | | | stamp die back to the machine for a 10 minute |
| Laser Engraved Rubber Stamps | | | | curing. Once the stamps are cured they can be |
| The traditional raw rubber used for vulcanizing | | | | cut up individually. Polymer sachets are available in |
| stamp dies is quite unacceptable for the | | | | a range of sizes up to A4 size. |
| production of laser stamp dies, the laser process | | | | Processing time is about 30 minutes for a batch |
| requires a very even thickness and blemish free | | | | of polymer stamps. |
| surface to produce an acceptable printed image | | | | Cost of polymer stamp making machines range |
| from a stamp die. The rubber must also be | | | | from $3,500 AUD for an Australian made unit |
| subjected to a specific curing process before it | | | | designed specifically for stamp making up to high |
| can be exposed to the elevated temperature of | | | | end imported units with computer controlled |
| a laser beam. | | | | washout for $15,000 AUD. |
| The depth of the engraving is determined by the | | | | Advantages - Lower capital investment, polymers |
| laser speed, its wattage and the density of the | | | | make almost clear stamps making them ideal for |
| rubber. For example, a 50 or 100W engraver will | | | | scrapbooking and card making. Stamp relief can |
| engrave the rubber deeper and faster than a | | | | be easily controlled during exposure. |
| 25W machine, which may require a second pass | | | | Disadvantages - Early polymers did not accept |
| to achieve a similar result. Usually supplied in an A4 | | | | inks as well as polymers available today, this along |
| size sheet form, a good quality laser rubber is | | | | with being new technology caused initial resistance |
| required for engraving stamp dies and must also | | | | to polymer stamps. |
| have suitable compression strength and ink | | | | Summary |
| transfer properties. | | | | Most large stamp manufacturers have a mix of |
| To assist the engraving process, it is necessary | | | | the above equipment. The unmounted rubber |
| to remove the excess dust which is constantly | | | | stamp dies produced with any of these |
| created by the laser cutting action with an | | | | manufacturing methods can be cut up and affixed |
| efficient exhaust filtration system. As very few, if | | | | to simple hand stamps, dater stamps or self |
| any, CO2 laser engraving machines were initially | | | | inking stamps. Craft stamps are usually affixed to |
| purpose built for engraving and cutting rubber, | | | | wooden blocks or in the case of polymer stamps |
| installing and maintaining an effective dust | | | | affixed to clear acrylic blocks with adhesives or |
| extraction system pays long term dividends. | | | | InstaGrip mounting mat. Various manufactures |
| Mirrors, lenses and any exposed bearing surfaces | | | | produces stamp mounts. Astron Industries in |
| should be cleaned thoroughly as part of a regular | | | | Australia manufacturer the clear hand stamp |
| maintenance program. Any neglect in this area will | | | | 'Vuestamp' and also distribute the Ideal range of |
| be detrimental to overall trouble free laser | | | | self inking mounts. Other brands of self inking |
| operation, as the build up of dust and residue will | | | | mounts are Trodat, Colop and Shiny. |
| affect running efficiency and the quality of the | | | | |