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Mold making

#1

Hello all. I made my first oven-vulcanized mold yesterday, with
disappointing results. I used an aluminum mold frame (borrowed),
two aluminum plates, and three “C” clamps, and pre-cut mold
rubber. The problem was uneven pressure, and maybe too much rubber,
since it oozed out of the sides. The mold is not usable.

I want to get into mold making cheaply. I so far own two cold
mold frames (came in a group of 2nd hand stuff) which I haven’t
used yet.

With my lack of success yesterday, I was looking in the Rio
catalog and saw a clamping device with 2 platens and a screw on
each end. Has anyone used this? Is this reccommended? Obviously,
I don’t want to buy a vulcanizer, but I need quality, consistancy
and ease of use. Any guidance would be appreciated.

-Elaine Luther
Studio 925
Chicago, IL USA

#2

Elaine,

I am a custom knife maker with some knowledge in casting. For a
mold that must hold high detail I use Polytec two part molding RTV
rubber in a container [tin can or metal tube]. The molding rubber
comes in different hardness ranging from soft to hard. This product
cuts open like regular jewelry molds. Polytek phone #
1-610-559-8626. They also have a webb site. Sorry, I do not have
the web site address at this terminal.

Jim
omf50@aol.com

#3

Elaine, I have used the Rio clamping device to oven vulcanize molds
and have had no problems . Rodney

#4

I’ve been using silicon molds for about 8 years now and find them
entirely satisfactory. The details are perfect, the stuff is used
cold in cardboard and no cutting is necessary. contact me for
more at @prycelessg

#5

Hello!

The vulcanizer in Rio is great. I inherited one years ago from an
artist friend who was dying of cancer. I used it for some
production work, but, I really haven’t done production work for
several years. I live in Northern Wisconsin and will be traveling
to Naperville to Ed Hoy’s International in the next month. Are you
interested in buying mine? I could bring it down your way and save
shipping. It is in perfect condition. How about $350? Also can
give you the rubber, forms etc… Can help you get started and
trouble shoot if you need help.

Or anyone else out there in need of a good buy on a vulcanizer?

Pat

#6

Elaine,

As I have stated before on numerous lists, why the hang up on heat
vulcanized molds vs RTV (Room Temperature Vulcanized)
materials??? RTV’s require no vulcanizer, most anything for
"frames" (I often use a piece of split plastic pipe), materials
costs are not too different (in fact RTV’s can be lots less than
heat vulcanized rubbers), the molds have great life, GREAT detail
pickup, are relatively fast (few hours to 1/2 a day), Etc. Look
into RTV’s, you might like what you find. I have been very happy
with quality, consistancy and ease of use. This is my humble
guidance suggestion.

John

John and Cynthia/MidLife Crisis Enterprises
Maiden Metals/C. T. Designs/ Bloomin’ Wax Works. etc.

PO Bx 44, Philo
CA 95466
Ph 707-895-2635 FAX 707-895-9332

The playfulness of the Universe
is reflected in the dance of the stars!

#7

Elaine, if you want quality molds without buying a vulcanizer i
suggest you use the room temperature vulcanizing rubbers. The only
thing you really need is a frame like the Ferris mold frames and a
vacume pump to remove bubbles, the pump is however optional if you
brush on a contact coat very carefully and do not mind a few
bubbles in the mold itself. I recommend the Dow Corning RTV
Silastic. The E or the L designated hardness. The green color is
the harder of the two and best for flat objects while the white
color is softer and better for intricate rings and delicate items.
I have used both of these for about 20 years with great results
even though i have a vulcanizer ther are some things that the RTV
rubbers are better for. I also understand Castaldo (the vulcanized
rubber manufacturers) have come out with a new room temperature
vulcanizing rubber for jewelers. Last but not least if you are
determined to vulcanize i suggest you try the red silicone rubber
from Contanti in fact I suggest anyone who is making molds should
try this. It is more forgiving than rubber and does not take as
much pressure or waste as it is more like a clay in the
un-vulcanized state. You do have to cook it about 45 to 60 min
longer than the rubber from Castalto.The silicone rubber is also
minimal shrink and leaves a shiny surface so the wax from your
injections comes out shiny. Good luck either way. Frank Houston, tx.

#8

Hi Elaine,

Regarding the casting,since you are in Chicago, if you decide to
farm out the casting I can reccommend Master Casting downtown at 5
n. Wabash.Thy know what they are doing, are honest so you don’t
have to worry about your mold getting away from you, and I believe
they are charging around $1.00 per dwt of finished silver
product.This also includes tumbling. They are also one of they few
places there that do Platnium.And, yes, they both can out to Eve
Alfille’s and did a slide lecture for AIM a while ago. Tell they I
say Hi! About the rubber mold, I’ve always used the machine.There
should be an easy way to correct the excess. I sometimes get a
slight amount of excess costaldo gold rubber at the top plate, but
I assume yours is unusable? Sounds like the two plates bent and so
to correct, a thicker backup on ea side of the clamp should help.
Is the clamp too small? Castaldo sends a sheet of problem
shooting, with ea. box of compound, that should be very
helpful.Double check temp. w an oven thermometer. Another thought
is to add heat plattens (or 2 dismantled Irons) onto the top and
bottom of that new hydrolic press that you got.Throw in a couple
of plates, set the temperatures on the Iron settings and away you
go. If you can’t find 2 irons, American Science Center( they are
in the book) should have heating plattens, or plates. Master
Casting will also make molds for you, call George for a quote. Don
Wollwage in sunny Ca where the weather has finally warmed up to 75
or more, with no rain in sight!

#9 
 As I have stated before on numerous lists, why the hang up on
heat vulcanized molds vs RTV (Room Temperature Vulcanized)
materials?????????? RTV's require no vulcanizer, most anything
for "frames" (I often use a piece of split plastic pipe),
materials

Okay, okay, I get the message, John and Margot. I’ll explain. My
bias toward vulcanized rubber is that I have spent more time
employed in the “fine” jewelry industry than in the “crafts
industry/community,” so I’ll I’ve ever seen is vulcanized molds.
My caster uses them, they last 20 years…So, ignorance! : ) Also,
because I didn’t want to learn to cut molds (anything I have to
wear a chain mail glove for, I don’t want it) so I wanted to do
separation molds, but now I read one can do separation molds with
silicone as well.

Thanks for opening my eyes! Thanks to all the wonderful info.
from everyone on mold making and casting, I really appreciate it.
This is a wonderful group of enthusiastic, generous people.

-Elaine Luther
Studio 925
Chicago, IL, USA
where it’s great kite flying weather!

#10

Elaine,

I know that much of the production end of the industry still uses
the vulcanized materials. Old habbits and processes are VERY VERY
hard to change in many if not most industries. As to needing s.s.
gloves to cut the molds, many of the RTV mold materials make a
softer rubber than the old vulcanized rubbers. Also, for ANY type
of mold rubber to be cut, always use a new, sharp blade, sergical
type blades verses some of the cheaper craft blades, and lubricate
the blade often while cutting (I usually use liquid silicon, but I
would substitute most any medium weight oil or even soapy water.
It is amazing how much the lubrication helps.

Yes this is a great group!!! I am on another list (ArtMetal at

(http://www.artmetal.com/village/)

will get you there if you or anyone are interested. There are a
number of jewelers on the list and within the village, there is an
intire “site” dealing with jewelry. There is also a great resource
list. Both the ArtMetal site and this site generate the same
amount of daily mail… lots.

Lastly, I would suggest that if you have never tried the RTV’s do
so. Some of the silicones give absolutely smooth finishes on the
waxes, almost to the point of being weard. Good luck what ever
way/materials you choose.

John

John and Cynthia/MidLife Crisis Enterprises
Maiden Metals/C. T. Designs/ Bloomin’ Wax Works. etc.

PO Bx 44, Philo
CA 95466
Ph 707-895-2635 FAX 707-895-9332

The playfulness of the Universe
is reflected in the dance of the stars!

#11

I’m a production you name it I do it ! Caster, mold maker,
finisher, etc, let me know what you need to find out!! Matt W.

#12

I’m interested in finding someone who makes quality metal molds
for my settings I use in my pieces. Any ideas?

#13 
   I'm interested in finding someone who makes quality metal
molds for my settings I use in my pieces.  Any ideas?

Are you after metal molds to make metal parts or are you after
some sort of mold to make waxes to then be cast into metal??? I
do the latter but not the former…

John

John and Cynthia/MidLife Crisis Enterprises
Maiden Metals/C. T. Designs/ Bloomin’ Wax Works. etc.

PO Bx 44, Philo
CA 95466
Ph 707-895-2635 FAX 707-895-9332

The playfulness of the Universe
is reflected in the dance of the stars!