Resin Casting Tips and Triumphs

[artdecovampire]

I studied sculpture at University and I have cast in plaster, aluminium and bronze on quite a large scale. I've never done small fiddly stuff in rubber moulds though. I've bought myself a starter kit and I'm going to start with a home made triceratops base for my vintage Pyro model I'm repainting. Hopefully I can duplicate it for the five others in the loft. I'd love to see any original or repro stuff anyone has done, particularly if you aren't a garage kit producer. saw the video below which might help or inspire anyone like me.

www.youtube.com/watch?v=LSH19G_6Yeo

[TAY666]

You want a little more info on molding and casting?
Check out this video series John did a year or so ago.
www.youtube.com/user/jayco40/videos

He's one of the old school casters still in the hobby.
Great guy, with some cool stuff, and a huge willingness to help others.

[prescenes2]

This is one thing I'd like to learn. I have watched countless videos of how to's and still a bit nervous about doing it. There's a lot of stuff to duplicate to make a forest or swamp.

[artdecovampire]

Yes, even with my experience of pouring bronze in to a ceramic shell in a foundry and sand casting Aluminium from wooden patterns, the thought of sitting down at a table and casting up a tiny flying lizard in resin scares the hell out of me! It could be the disapproving looks I got from the wife when I brought the chemicals home and she had that 'Not another hobby' look on her face. John's video is fascinating. Trouble is it tempted me to start something morecomplicated, though I'm actually going to force myself to start with a one part base

[TAY666]

I've thought about doing it, but just never put the money together to give it a go.
Seems pretty straight forward to me.
But that just might be because I already do a lot of stuff with my hands, beyond modeling.
Construction, home repairs, I worked in injection molding for 17 years, and the past 7 years have been spent doing sheet metal fabrication.
So, in my mind, making a mold, and pouring resin shouldn't be much harder than using self leveling cement to smooth out a floor before laying tiles.
Sure, there will be a learning curve as you figure out all the problems and solutions to them.
But that is just like doing a model really. Practice makes perfect.

[artdecovampire]

Here is my clay original for the Pyro Triceratops base. Plenty of rocks and a few ferns on the ground. I'll post the picks of the next few stages later in the week as I go along. Fingers crossed.

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[TAY666]

Good luck.

[artdecovampire]

Well here goes. A picture of my base in its casting box. Made form clear acrylic held together with a glue gun. The parts for this can be reused. Its sealed with glue gun glue but also plasticene. Belt and braces of course. I shall be pouring the rubber today. I have also sculpted a small tree to be cast and glued on to the edge of the base. This will be a small two part mould to practice. Its clear so I can see what's going on inside.

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[scooke123]

Good luck!!!

[artdecovampire]

Thanks to you both for the wishes of luck! It does seem that its a big part of the process.

[artdecovampire]

Well here is the report so far. To the more experienced modeller this won't be news, but to everyone else some tips I would like to pass on.

1. I worked out the volume of my box very carefully, mathematically, to the top of my original base former. I thought that the former, once in the box would displace enough silicone rubber to cover it and form quite a thick top to the block. Despite this I needed to add a bit more to make the rubber mould look thick enough to take casting punishment.

2. Silicone is very expensive and difficult to measure out. It sticks like honey to a blanket to use a polite term! Once you see how much you are using you start to feel the cash draining out of your pocket.

3. Measuring out small amounts of catalyst accurately is also very difficult. Use a syringe if you can find one.

4. Use disposable mixing cups as cleaning up is a nightmare. Use latex cloves too as I forgot on the second pour and its hell to get off your hands and clean up.

5. It doesn't smell too bad, unlike resin, though plenty of newspaper and ventilation goes without saying.

The good news is I'm still excited and looking forward to giving all my deserving Pyro-Lindgerg Triceratops' a nice new base each.

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[TAY666]

Glad to hear that things seem to be going ok so far.
Sounds like it would be easier if you were using an RTV with a 1:1 ratio, that way you wouldn't need to worry about the small amounts of catalyst.

I hear you on the amount of waste. I know from watching John's videos, there is quite a bit that ends up stuck in the mixing containers. Both RTV and resin.

[artdecovampire]

Thanks TAY. The resin I am using is a 1:1 mix so that should be easier. I used the 100:5 silicone because it was the only one I could purchase locally in quantity. That turns out to be over £20 per Kilo plus tax. I don't know what that is in dollars, but it works out at 6 Pints of warm British beer, or as my wife pointed out, 3 decent bottles of wine. John's video was an inspiration, can't thank you enough for putting me on to it. I can see why Alchemy or Prehistoric plastics charge a lot for the add ons. They must be doing it primarily for love and respect because the sculpt, the mould and then the pouring must run in to 100s of hours labour. I'm not deterred though and I intend to make a small PS style articulated dinosaur figure when I have the time, or at least a 'What if?' but for a Lindberg model. Perhaps a Lambeosaurus head for Corythosaurus as that body has plenty of potential.

The next bit is the tree, a two parter. Johns way of removing the air from the mould using channels is a bit like runners and risers in a sand box or lost wax cast but his channels just provide space as opposed to reaching the surface. This saves resin as you don't get loads of sprue.

[artdecovampire]

PS. Is there anyone else out there with something to show? I'd really be interested in seeing them, or even swapping casts.

[TAY666]

Yeah, molding and casting resin kits is costly and labor intensive.
Not to mention somewhat hazardous due to the various gasses and such during both phases.
Then when you get into doing it more professionally, the costs of a vacuum chamber to degas molds when you make them. And pressure pots to pressure cast the resin.
You gotta love what you do in order to do that stuff for very long, or in large quantities.

[artdecovampire]

Well I pulled out the vinyl from the box. I then took out the original which proceeded to fall apart. nits of it wedged in the vinyl because of slight undercuts. The original was made out of bits of scrap so its not important, it just means the mould now needs cleaning up a lot more than before.

[scottbanks]

I haven't had time to work on any sculpts or casting lately, but I will post some soon. Are you working on any 2 part castings of 3d sculpts?

[artdecovampire]

I do intend to work on some smaller 3d sculpts. I have done figure modelling of humans and animals for the Staffordshire ceramic industry years ago when I left art school. They tended to be pretty big, so working small is going to be a test. It sounds weird but doing the sculpt doesn't worry me, its making the moulds. I'm experimenting with some tree fern trunks and cycads which can be used on a range of PS models to enhance them. I then intend to make a small Dino figure as practice. Something chunky, maybe a simple two piece. A prehistoric horned turtle for the swamp perhaps. Then on to a bigger PS add on. All the truly iconic creatures are done, so I thought a very active looking Ceratosaurus, smaller, more active (with all four finger claws!). Something distinctively not just an add on part, but at the same time toy-like like the PS Allosaur. My disposable income this month has gone as far as the wife is concerned so I need to buy more moulding materials. The base mould I made did three pulls in the end. There were too many tiny undercuts which trapped the curing resin and ripped it up. I need to sculpt a lot more simply. Those 3 bases worked out expensive in the end.

[scottbanks]

These are 2 casts I just finished as alternate bases for Alchemy Works Edaphosaurus and Polecanthus

[scottbanks]

Polecanthus base