I need the KNOW on casting and molding

skupilkinson · Post by **skupilkinson** » Mon Aug 28, 2006 5:30 am

Hi guys,

I was wondering if some kind person would mind telling me how to bext go about molding and casting? I'd like to know for the future, I'd like to make recasts of my models so that I can later use them for kitbashes. I'd like to try kitbashing but don't want to have to nuy kit after kit just to destroy it for a bash that may go wrong or something.
Also, some in the uk would be handy purely because they might know stockists of supplies local to me. Though I'll gladly take advice from anyone no matter where you're from.

Thanks a million

Skip

tonyG2 · Post by **tonyG2** » Mon Aug 28, 2006 6:34 am

There are loads of articles and "how" to tips at SSM.

First off, check this thread

http://www.starshipmodeler.net/cgi-bin/ ... hp?t=34287

These links are the best I've found - but thats just my opinion.

http://www.childofmecha.com/Modeling/Re ... Resin.html

http://www.childofmecha.com/Modeling/Re ... y/Clay.htm

Cosmo's basic article here http://www.starshipmodeler.com/basics/jc_molds.htm

and a detailed project article here http://www.starshipmodeler.com/projects/jw_resin.htm

skupilkinson · Post by **skupilkinson** » Mon Aug 28, 2006 8:10 am

Thanks very much,

Thay've been informative. I'm needing this info for recasting the 1/1400 enterprise D amongst others I'd like to kitbash a new design of starship. Like a mascott ship for myself.
What's the best method to use for each of the different parts of this model?
This isn't going to be done anytime soon, but I like to plan and prepare.

tonyG2 · Post by **tonyG2** » Mon Aug 28, 2006 8:19 am

There is an ongoing thread over at 1/2500 forums of casting an Ent D saucer for conversions which will probably be useful to you.

skupilkinson · Post by **skupilkinson** » Mon Aug 28, 2006 8:25 am

Yeah, I've read some of it but would the same rules apply here being as the size is different and there's more detail to take into account. I also want to copy the other parts like nacelles and engineering hull.

tonyG2 · Post by **tonyG2** » Mon Aug 28, 2006 9:08 am

Main problem with a 1/1400 EntD is the size.

You can't get past the problem of the saucer size so you need to be ready for using a LOT of rubber.

The second problem is again size related and is the amount of resin you will use. Thats a huge amount of resin and will weigh a TON. So you really want to try to make it a hollow cast.

Two ways I know of to do it (but haven't tried) are either to create a blank that hangs into the mold half or else prepare a strandard two parter mold but pour in a limited amount of resin and then rotate the mold in three dimensions. You can buy both manual and powered rotocasting frames and its worth looking for these on ebay.

modelnutz · Post by **modelnutz** » Sat Sep 16, 2006 11:00 am

There's another technique for creating a part like your saucer.

I'll try to be brief.....
The process starts with a standard 2 part mold formed from your master.

next, paint some urethane over the entire cavity covering all that nice detail with a thin coat of plastic ( you'll see why in a moment )

Then, roll out some clay ( non-sulfer ! Very important ! ) to whatever thickness you wish for your final wall thickness ( 1/8" is good )

Press this clay into the mold striving to keep a consistent 1/8" layer overall ( this is where the urethane really pays off...the clay will not stick to silicone but it will stick to the urethane so it should stay in place)
When all is coated with an even layer,add another layer all round the rim..trim the clay at the mold part line ( you should end up with a 1/4" thick edge at the rim)

Add any internal details or bosses as required

set your mold/plastic/clay cavity side up into a mold box and coat well with a good mold release
(Oh yea...almost forgot...cut some plugs out of the mold to act as alignment pins)
pour silicone over it to create a core mold of the inner surface.

Repeat for the other half of the saucer

Remove the master from the cured mold, add pour stubs and vents and cast away !
If you have done it correctly, you should end up with a 2 part saucer that has all the details but is only 1/8" thick thereby saving on resin as well as reducing the overall weight of the casting. If your careful trimming the clay you will not have much cleanup at the seam.

Sounds complicated, but it's actually pretty simple if you have molding experiance.