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Molding Trackside / Flatcar / Freight Objects

Started by OkieRick, April 18, 2009, 12:02:57 AM

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OkieRick

Or "Make it yourself."

Has anyone had any experience making mold(s) from liquid latex, wax or plaster and casting your own trackside figures? (trash piles, animals, car loads, etc.?)  I sent email to Woodland Scenics re: bulk purchse of cattle figures.  I want 200 minimum. The reply was they'd be glad to sell be 40 catte scene paks of 6 each at regular price.

I've seen latex used for rocks & rock side / cliff side molds.  Plaster cast & sculptured glued on.  I'm thinking of molding some cattle I already have using liqiud latex & greased or oiled cattle - about 10 per mold.

Anyone expert in doing this?  Ideas?

Rick
Invacare 2-2-2 TDX5 Tilt Recline & Elevate - 24v - ALS Head Control
God Bless Jimmie Rogers the Singing Brakeman

Jim Banner

Latex moulds show all the fine details but generally are not stiff enough to faithfully reproduce the large details.  Making a backing mould out of plaster of Paris helps, but must be done while the original is still in the latex mould.  Unlike many other moulding materials, latex will usually stretch enough to come off three dimensional objects (like cows.)  The problem is that while latex works well with plaster, it does not like to release from plastics and most mould releases needed for plastics will attack latex moulds.  And plaster is generally not strong enough in small cross-sections (like cows) to allow the latex to be peeled off.  You might try some of the stronger plasters, like Hydrocal or dental plaster, perhaps even adding some carbon or glass fibre to the plaster.

Moulds made from one and two component silicones will work with polyester resin plastic, but for something like your cows, you will probably need a two part mould.  Check out a cow under a good magnifying glass and you will see the parting lines where the two or more pieces of the mould met.  Mold-All is a brand of 2 part RTV Silicone that I have had good luck with.  Used with Cast-All, a two part casting plastic, you do not have to use mould release.  There is more information on page 63 at the link below:
http://www.aaasupplyhouse.com/aaacatalog.pdf
I have dealt with AAA Supply both in person and by mail order for many years and found them easy to deal with and helpful.  There may be similar suppliers in other countries as well.  On that same page, they list a conditioner/mould release for latex moulds.  So there is hope in that direction too.

It is also possible to cast figures using molten metals poured into plaster moulds.  The plaster mould is ususally poured around an original carved in wax, then heated to melt out the wax and dry the plaster before pouring in the lead, bronze or aluminium alloy.  This is called lost wax casting.  A variation is to put the moulds in a centrifuge-like device and spin them while pouring to assure the molten metal is forced into all the fine corners of the mould.  This is known as spin casting.  Detail parts from Miniatures by Eric were made this way.  Unless you are very sure of what you are doing, casting in molten metals is best left to the pros.

Large companies like Woodland Scenics or their supplier cast figures by the millions by injection moulding styrene and other plastics.  In the time it takes you to cast a batch of cows, they probably knock out 10 thousand.

Another alternative to making your own is to buy unpainted figures in large numbers.  I have bought several hundred 0-scale human figures on eBay, mostly from a Hong Kong seller using the name Wehonest.  The all up, FOB Saskatoon price was about 17 Canadian dollars per hundred.  They came as a bunch of each of 6 or 8 different figures, moulded in a rubbery plastic that is easy to cut and glue and modify with dabs of Squadron Green body putty.  In this way, I have been able to produce dozens and dozens of 1890s O-scale figures for my On30 layout with no two alike and for less than 20 cents per figure.  (And I had a ball doing it.)  But I am thinking that in a herd of 200 cows, nobody will notice than many of the cows are clones of other cows.  But then again, maybe that is just the impression of us city folk.

Growing older is mandatory but growing up is optional.

pdlethbridge


BillD53A

I believe there is a 'Casting' list at Yahoo Groups

OkieRick

#4
PD,

Here where I live in North Easterly Oklahoma, 60 miles North of Tulsa on HW 75 and only 11 miles as the crow flys South of the Kansas state line, the jackalope haven't migrated this far South or West.  Out in the panhandle of OK and Texas around Guymon and Amarillo you start getting West enough to see the jackalope.

I think we get too much annual rainfall for the jackalope here.  We are however starting to see an increase in the numbers of hoot'n'nannys. I imagine there are folk on this forum who have heard of these animals but have no idea what they are.  The hoot'n'nanny is the offspring of a Winter mating of a Horned Owl and a female goat, aka doe goat, dam goat, nanny goat.  Goat ranchers have been overheard in many coffee shops expressing sorrow at the loss of spring milk goats due to owls & nannys mating.  They're usually muttering or swearing, "Does dams nannys goats!"

honest.

Rick




Invacare 2-2-2 TDX5 Tilt Recline & Elevate - 24v - ALS Head Control
God Bless Jimmie Rogers the Singing Brakeman

Chris350

Quote from: OkieRick on April 19, 2009, 08:51:05 PM
PD,
...
I think we get too much annual rainfall for the jackalope here
...
Funny out here in The Rockies we have a similar phenomenon.  IF you get up to a high enough elevation, the Deer turn into Elk.
Really.

Jim Banner

We used to have jackalopes, elk and even moose around here but the mosquitoes carried them away.

Jim
Growing older is mandatory but growing up is optional.

train with no shame

hey okierick .i just got the walthers flyer catolog .on pg 42 they have your beef cattle .
walthers cornerstone series item# 933-3143 beef cattle pkg of 16 for $7.98 regards mark f

train with no shame

also on pg 43 brown and white cows pkg of 30 item #590-14409  $37.98  :-[


OkieRick


Thanks fellas!  I saw my Walthers catalog today but haven't taken a look at it yet.

SF - thanks for the article - it helps me understand Jim's instructions.  I hope I can get someone here on this farm to help me at least try to mold & cast.

Thanks again,
Rick
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Invacare 2-2-2 TDX5 Tilt Recline & Elevate - 24v - ALS Head Control
God Bless Jimmie Rogers the Singing Brakeman