- Hi All! Just a few suggestions about terminology, so that we all
understand each other. These items will be added to the glossary as I
build it. Please post any suggestions for modifications to this
Pattern: This is the original model, made by the model-maker. There is
only ONE pattern
Master: This is what the production molds are made from. It can either
be the original Pattern, or a first generation copy of the Pattern. In
cases where you need many molds to produce parts, or the Pattern is
particularly fragile, multiple patterns made from the first mold are
usually used as "originals" to make more molds.
Breeder mold: A breeder mold is a single mold of the original pattern,
that is used to cast a number of parts for re-molding. i.e. I made only
1 (one) side step for my latest model train. I then made a breeder
mold, cast 4 (four) copies in it, and used the 4 copies to make another
mold. This way I can cast an entire train's worth of ladders in one
RTV Rubber: "Room Temperature Vulcanizing" Rubber. This is the
mold-making material of choice for many people. It consists of a mold
base, which is a gooey liquid (usually the consistency of honey) to
which you add a catalyst (a thin liquid), and then pour over your
pattern (which is enclosed in a box) The rubber then sets up at room
temperature, in anywhere from one hour to 24 hours, depending on the
catalyst you use. There are fast-setting catalysts, catalysts that allow
you to pour low-temperature molten metal into the mold, and catalysts
that give the rubber a much thicker consistency, so that it can be
painted on vertical surfaces. These rubbers vary in hardness and cost.
More on this later.
Polyurethane resins: These are very popular casting materials, that
usually consist of two liquids that are mixed together in a specific
ratio. Many are mixed 1:1 or equal parts of each. They set up in a
variety of times, from 3 minutes to 24 hours, depending on type. They
can usually be filled with various additives, including glass
microballoons, metal powders, porcelain powders, wood powders, etc., to
simulate various materials. "Cold Cast Bronze" as advertised in
magazines selling copies of sculptures, is actually polyurethane resin
with bronze powder added. When the resin is set, the piece is burnished
with a wire brush to show the bronze coloration in the plastic.
Mold enclosure: This is the box the pattern sits in to allow it to be
molded. Enclosures are made from many materials, such as plastic, wood,
lego, or existing containers.
Well, there's a start! I'll keep adding more as I go.
- David wrote:
>From: D Holliday <dholliday007@...>Hi David! Did you ever register as a OneList user? I guess you must
>I can access Onelist, but can only "log out", not "in"!
>What do I need to do to get in?
have, because I got your post! Are you entering your full e-mail
address in the box on the welcome page? Just your name won't work. Let
me know exactly what you're doing, and I'll try to straighten it out.
Regards, and welcome to the list!
This is a whole lot more interesting than Haggis.
I'm not familiar with the process. It looks like I'm in a webpage. Do I
respond as such (how?), or do I look for some newsgroup icon (how?).
"It" says I'm "in", but then what do I do, and what does it mean?
You'd asked for personal details (sans "little blue dress") but I don't
know how to put in my desires (lotsa GN Electrics).
How do I communicate?
- Can somebody answer a linguistic point for me?
A 'master', to me, is an object that looks like the final shape
of the casting. A gaming figure master is a (positive) little guy.
Because I use the CNC, I don't generally have 'a little guy'.
I'm much more likely to carve out a hole in a block of wax. In the bottom
of the hole is half of a positive, with the parting line and keys.
I fill this with RTV and get half a mold. Then I cut the other half the same way.
So, is there a technical term for these wax blocks?
I know that in sand casting of metals they call the half-an-object-and-part-line
pattern a 'mold board'.
Need motors? HOn30? Try Annie's Depot -
Anne Ogborn wrote:
> Can somebody answer a linguistic point for me?
> A 'master', to me, is an object that looks like the final shape
> of the casting. A gaming figure master is a (positive) little guy.
> Because I use the CNC, I don't generally have 'a little guy'.
> I'm much more likely to carve out a hole in a block of wax. In the bottom
> of the hole is half of a positive, with the parting line and keys.
> I fill this with RTV and get half a mold. Then I cut the other half the same way.
> So, is there a technical term for these wax blocks?
> I know that in sand casting of metals they call the half-an-object-and-part-line
> pattern a 'mold board'.
> Anne Ogborn
- Larry, so the things I'm making are also 'masters'?
If so, is there some way of distinguishing them from the
'looks like the final object' variety?
Need motors? HOn30? Try Annie's Depot -
- -----Original Message-----
From: Anne Ogborn <anniepoo@...>
To: firstname.lastname@example.org <email@example.com>
Date: Thursday, March 21, 2002 2:04 AM
Subject: Re: [casting] Terminology
>Larry, so the things I'm making are also 'masters'?I could be wrong , but shouldn't the masters look like the final object?
>If so, is there some way of distinguishing them from the
>'looks like the final object' variety?