RTV labling

Hi does any one have something to label rtv molds. we’ve tried markers but
they rub off. any suggestions would be apresiated

Bob Martin
Hoff jewelers
St.Paul, MN.

Dear Mr. Martin,

If you use our new CASTALDO LiquaCast RTV rubber ( which is stronger,
easier to use and cheaper than silicone RTVs) you can write on the
resulting molds with an ordinary marker

If you must use silicone RTVs despite the disadvantages, the only solution
is to mold the markings you want into the rubber itself. It’s easily done.

Do you have a Dymo plastic tape marker?? The kind that embosses letters on a
self-adhesive label tape? If so, merely emboss what you want to write, mount the
tape (outside-in, of course, so the image won’t be reversed) in the mold frame and
pour as usual.

Your finished mold will be permanently molded with the info.

By the way, this works just as well with vulcanizing rubber except that
you have to buy special aluminum tape ( made for plant nurseries, etc.)
instead of plastic tape for obvious reasons.

Are you ( or anybody else out there ) interested in a free sample of our
new LiquaCast RTV rubber??? If so, please send me your shipping address–
no P.O. boxes.

Michael Knight

Stamp a metal plate with the identification and theninclude that in the
mold frame

I don’t do much rtv molding, but I’ve used a wood burning tool in the
Ron Charlotte – Gainesville, FL
afn03234@afn.org OR @Ron_Charlotte

I am assuming you are talking about the silicone RTV. Take a red hot wax
tool and write into the surface of the molds you have already made the
silicone RTV will turn to ash that can be wiped off.In the future write
with wax on the mold frame to get a negative number or brief description in
the mold. I use a little sticky wax on the surface of the mold plate.

Hey Bob!

A sharpie marker will work as well as any, but you have to remark the mold
once in a while. If you use the mold a lot take your scalpel and cut the
number in it.

I have heard of using a different color silicone to paint the numbers on.
Kind of like quill and ink.This will work if it is the same brand of

I’m open for suggestion on this on too.
Best Regards,
TR the Teacher & Student

this is a bit of a bother, but it works… If you use a wax pen to "write"
an identification marking, in wax, on the inside of one side of your mold
frame for liquid type poured molds, then after you’ve finished the mold,
there will be the little depressions left by the wax on the surface of the
mold. If those happen to spell something useful, then you’re mold is
nicely marked. One caster I know has made up little zind etched logos
(graphics arts places do the etching cheap). All his RTV molds, as well as
his vulcanized molds, have a nice little logo impressed into their surface
by including one of these small reusable plates inside the wall of the mold
frame. You can also get “reverse” letter and number stamps. Stamp
appropriate numbers or letters on a bit of scrap metal, in reverse, and
include that inside the mold frame… Easier than doing it with wax and
looks better too… All of this, of course, assumes that you know when
you’re making the mold, what you want to label it with already.

peter Rowe

Your suggestion to write on the mold frame to make a permanent impression
on the mold is fabulous! I’m not a mental giant and my magic
marker has seen a fair amount of use. I’ve tried burning the mold but
don’t uch care for the fumes. Like the permanent indention from molding
much better. Thank you!

I model a number or a letter with plaster (very small) and paste them in
one of the walls of the mold container, then I pour the liquid RTV. It
seems like it have been carved after the silicone is cured. I hope it helps


Since I’ve started using the clear RTV I place a short slit at the backend
of the mold and insert a paper label. I keep meaning to place a label in
the rubber before it cures, but haven’t done that yet.

I once did a piece that had 30+ similar looking units and molded them in
white RTV. Not wanting to have ink wear off I made numbered plates and
attached them to the inside of the mold frame as others have suggested.

Since the impressions from the stamps I have read correctly I stamped a
piece of copper with the numbers and made wax impressions of those to use
in the mold frames so the marks on the rubber read right.

If I were to do this on a regular basis I’d get a set of reverse stamps.
Then the second impression (in the rubber) would read correctly.

Dick Caverly

I’m interested in your new LiquaCast RTV rubber mold material and any help
with actually cutting a mold apart.

I have some antler carvings that my husband did before he died that I
would like to reproduce, would this be a good material for that?

The only mold making I have done is flat backed with RTV, these would be

Cass Jones

Has anyone used one of the embossing lablemakers with the adhesive tape ?
If it were lightly adhered to the mold surface and allowed to embed into
the mold it would be permenant enough. The marking would also be very
plain to see if allowed to just reverse mold the letters and figures into
the mold.

Hi Robert I have been using aluminium(non-adhesive) label making tape with
a machine similar to a dymo labelmaker for about 20 years .It is easy to
use, cheap and works on all types of rubber , vulcanized or self
curing… silicone ,rtv and natural rubber as well as rubber for white
metal (pewter based) casting.The aluminium tape is available from Grainger
in a 10 roll pack (inexpensive). # to all mold makers… try it , you’ll
like it .shure helps to keep the molds organized. Daniel Grandi
http://www.racecarjewelry.com visit the web workshop for ideas. We also
do casting/finishing in gold,silver and bronze for the jewelry trade.