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"Mould Release Agents" Topic


15 Posts

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745 hits since 15 Jun 2016
©1994-2017 Bill Armintrout
Comments or corrections?

Kropotkin30316 Jun 2016 2:40 p.m. PST

Hi All,

Some one was criticising GW new product and said,

"Agreed. Very soft edged. Like they've used vaseline as mould release. Not up to usual standard."

I use vasiline as a release agent and I find for my drop casting moulds that detail can be lost. I use silicone rubber RTV moulds. Question is what else could I use for a mould release agent? Truth be told I don't go over the top on the use of vasiline, only tending to coat the silicone rubber parts of the mould rather than the masters.

So what do people do to get a better definition on their castings if drop-casting?

Any thoughts appreciated.

DyeHard16 Jun 2016 2:45 p.m. PST

There are spray on release agents such as Mann:
link

I find these allow very shape detail.

More to select form:
link

RavenscraftCybernetics Inactive Member16 Jun 2016 2:51 p.m. PST

talc

Personal logo Dye4minis Supporting Member of TMP16 Jun 2016 3:02 p.m. PST

+1 for Talc (baby powder as well)

RudyNelson16 Jun 2016 3:17 p.m. PST

Talc has been used by every company that I communicated with since the 1980s.

Mako11 Inactive Member16 Jun 2016 9:53 p.m. PST

If using silicone, most items don't need a mold release agent.

Bill McHarg Supporting Member of TMP Inactive Member16 Jun 2016 9:54 p.m. PST

You need talc with no perfume. If there is a dive shop in your community, they will sell it.

Personal logo Ironwolf Supporting Member of TMP16 Jun 2016 10:30 p.m. PST

As Mako11 posted, I don't use anything with my silicone.

GarrisonMiniatures Supporting Member of TMP Inactive Member17 Jun 2016 1:30 a.m. PST

I used talc. I've found that it does make a difference.

Moonraker Miniatures Inactive Member17 Jun 2016 2:22 a.m. PST

Talc

shaun from s and s models Supporting Member of TMP17 Jun 2016 3:46 a.m. PST

we use a silicone spray if using resin, talc if using metal
are you in the uk? if so toolstation and screwfix both keep it.

Master Caster Sponsoring Member of TMP18 Jun 2016 4:49 a.m. PST

Krop,
You're probably losing detail more from the drop casting (gravity) method than anything else. On RTV molds I use strictly Vaseline petroleum jelly right out of the jar and applied with a small paint brush just on the RTV not the model(s).
I apply very thin coats and then smooth the surface with my finger to eliminate globs of jelly.
On black vulcanizing rubbers I use strictly Gold Bond (talc) powder here in the states as a separator between mold sections.
These are the only two products I use for mold separation. And yes, I have tried many sprays in the past and always return to the tried and true. Most but not all spray releases are best used to help separating the molds from their mold frames.
Toby Barrett

Kropotkin30318 Jun 2016 6:02 a.m. PST

Thanks gents,

I will look into silicone spray I think. The vasiline is used when pouring the second half of the mould, after the first half is set, to prevent the second half sticking to the first half.When it comes to pouring hot metal to make the figures that is when I use talc.

Black Hat Miniatures18 Jun 2016 6:47 a.m. PST

I use formula 5 from ambersil for mould release on silicon drop cast mould for resin. It's a wax….

Mike

DyeHard18 Jun 2016 8:26 a.m. PST

Since you mentioned RTV, I assumed you were casting with resin. That is why I suggested the spray.

For multi-party molds, when coating the first part to prevent the rubber from bonding to the next, Vaseline is actually a very good pick. You can thin it with paint thinner or by a pre-mix like this: link

For casting metal in rubber, one dose not really need a release agent. As stated above talc it often used to aid in the flow of the metal and to provide very small amount a extra air flow.

Be careful about metal in RTV. It is not able to handle the high temps that vulcanized rubber molds can. Make sure to read the limits on the rubber you are using and try and find an alloy that melts below that.

For a little "How To" on resin casting here is a page I put together many years ago:
link

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