Stamp Process Info - was: Is this list always quiet?

Hello, my name is Rodney Grantham and my experience
with various stamp making processes goes back
over 30 years.

The least expensive method is to carve rubber erasers,
but requires a lot of skill and patience.

Liquid photopolymer is fast. Dies can be made in about
15 minutes exposed through a negative transparency
you've created on your computer, and exposed with
ordinary black light fluorescent bulbs. Photopolymer
can get a bad name since it's clear and doesn't look like
red rubber. Also, there are so many durometers and
formulations designed for flexo, pantograph masters,
pad printing and ADA signage. Folks try to use these
and do not get good results.

We use and prefer liquid 40 durometer photopolymer for
making both custom stamp dies and printing plates for
wooden tokens. The image quality of photopolymer is
actually better than vulcanized rubber since it's a first
generation die.

Liquid photopolymer should be only be exposed with
fluorescent black light bulbs, like the F20T12BLB,
available even at Wal-Mart. Avoid incandescent blacklight
bulbs. Heat from these bulbs lowers the viscosity of the
liquid photopolymer and it continues to "move" during the
exposure making a poor die.

Vulcanized rubber stamp dies in today's environment
are best suited for mass production, like art stamps.
Vulcanized dies are made from a zinc, magnesium
or hard photopolymer masters. This master is impressed
under heat and pressure into a matrix board. From
this matrix board, many hundreds of vulcanized rubber
dies can be made. Gum rubber is relatively cheap,
usually less than 2 cents a square inch. Vulcanizing
time cycles of about 4 minutes, makes this the material
of choice for multiple stamp dies of the same image.

The down side is the cost and time to make the master
and matrix board. Hard sheet photopolymer can be
processed by hand, but it takes about 5 minutes and
needs to be air dried at least 4 hours.

Another vulcanizing process uses engraved matrix
boards. Folks with an engraver can engrave their
design in hard board and vulcanize the rubber directly.

Back in my early graphics experience we made stamp
dies using a Linotype and Ludlow for lettering, and zinc
engraving for illustrations. Most newspapers of the day
were printed letterpress and used that technology. Using
foundry type for stamp dies ruins it for printing and
most print shops considered it a bad idea to use it
for making rubber stamps.

The folks at Brother make a system that incorporates
a stencil created in their machine. It's quite fast.
The down side is the cost of the machine and you
have to use their mounts.

Laser engravers are getting more affordable. However
to get any volume, a 50 or 100 watt engraver is
recommended. Also, the fumes must be vented
which also adds to the cost. The advantages are
stamp dies are made very quickly and pre inked
rubber is available.

Pre inked stamp dies made by vulcanizing, whether
salt leech or the gel process requires more equipment
and very accurate temperature control.

There are many choices and there is no good or
bad process. Each material has it's own features.

Hope this helps

Rod Grantham
http://www.granthams.com/