Casting and mold making?

[TURBULENCE]

I'm about to dive in to casting certain components and hard to replace/rare bits. For my own personal use of course. But other than what I've occasionally gleaned here I'm in the dark about the process. My search-fu is falling me, anyone able to provide some guidance or link me to some resources?

[Grotsmasha]

I'm pretty sure Subtle Discord has gone into it at length here in PCA, I'll try find it.

[Major_Gilbear]

My search-fu is falling me

 

Really? I've just Googled "Casting Miniatures", and got a ton of relevant hits straight away. :)

 

If you've already done some research, I'm guessing that you already have the gist of how to make moulds and cast parts. Therefore, is there any specific area that's causing you some issue? It might be easier to assist you with specific details rather than just writing a colossal wall-o-text on every possible variable of the whole process!

[TURBULENCE]

I haven't even started yet so wall to wall is kind of what I'm looking for. A list of materials I should start purchasing would be the best start however. To be honest I only really searched the forums, I trust the talent here more than Google

[Beaky Brigade]

I haven't even started yet so wall to wall is kind of what I'm looking for. A list of materials I should start purchasing would be the best start however. To be honest I only really searched the forums, I trust the talent here more than Google

 

I did a little one piece casting a while ago. It's probably worth doing wider research as there's lots of casters in things like prop building or other hobbies that do really complex stuff which is worth knowing even if there are no skulls on the items ; ). Warseer used to have a great section on this but unfortunately it was lost when they last went down.

 

What materials you need will depend on what you are casting, there is 'press moulding' that only needs materials like or similar to green stuff, or there is casting using two part resin, which is effectively what people like Forge World use. (or metal or plaster of paris, but you probably won't use that).

 

The difference between beginner and advanced casting is using one piece or multi piece moulds. A one piece mould is very easy to make, but is not really suitable for complicated items like full figures. Imagine an ice cube tray, that is a one piece mold.

 

See if you can get some old lego or duplo from a charity shop or ebay as that is a great tool to make your outer molds from. Don't waste money on new blocks!

 

For casting two part resin you will need an epoxy and hardener, and silicone and a curing agent to make the actual molds. There are starter kits available, but they are probably less good value than buying some of the items individually. 

 

You will also need plasticine to seal your moulds, make sure it's sulphur free as that reacts with silicone.  Weighing scales accurate to the nearest gram (or non metric equivalent) will be useful for measuring the correct amounts when mixing by mass.

 

Disposable items that are recommended include plastic measuring cups (don't get ones that are too large or small for the amount of resin you mix), stirrers, protective gloves and eye protection and a appropriate respirator is important too.

[TheOneTrueZon]

If you want some basic how-to videos, check out the Smooth-On site. They're the go-to source of materials for the professional visual effects market, but they cater to all skill levels. They do a good job at explaining the basics.

 

https://www.smooth-on.com/tutorials/

[Major_Gilbear]

I haven't even started yet so wall to wall is kind of what I'm looking for. A list of materials I should start purchasing would be the best start however. To be honest I only really searched the forums, I trust the talent here more than Google

 

I was going to post that same link as TheOneTrueZen.

 

On reflection though, there's rather a lot of cheaper and less messy ways to make moulds and cast parts. Can you at least indicate what sort of parts (size, complexity) and the number of casts you'd like to make?

 

For small details putty push-moulds are very effective, and you can make casts with putty.

 

For smallish parts, which you may want a few of, you can use a silicone putty or a thermoplastic like Oyumaru to make moulds with, and putty or resin to cast with.

 

For bigger or more complex projects, or where you need a higher number of casts, or where the detail you're looking to capture is very fine, then a silicone mould (like the Smooth-on tutorials) with resin casts probably better. Even then, some items may still benefit from single or multi-part moulds.

[NiceGuyAdi]

As others have said, depending on what you're casting will affect your approach, but I found this post very helpful and thorough. All the Sniper Scouts in my WiP had their sniper rifles casted with this method.

[Subtle Discord]

As others have said, this can be a large can-o'-worms to open, depending on just how elaborate you want to get and how large of a budget you want to invest. Based on the current feedback, tell us a bit about what do you want to get from the process and we can better tailor our responses. For under $50 you can get all the materials you'll need to do press moulds for simpler replications; for roughly $100 you can get all the materials to do simple RTV rubber moulds and use 2-part urethane resin to create higher quality replications, and for roughly $250+ you can create a Pressure Chamber to push the quality even higher; beyond that price point you're looking at investing in a Vacuum Chamber which pushes the process even further. The largest return on the investment will be seen in the quality of the parts created and how much work will be required after casting to deal with defects like bubbles; basically, more money and labour equals cleaner casts that need less cleanup.

 

One key thing to remember is that casting materials do have a shelf life; RTV rubber compounds will thicken and the 'A' compound of casting polyurethane will turn to 'slush' as it slowly reacts to the moisture in the atmosphere. If you want to go this route just be aware that you don't want these materials sitting around for longer than 12 months or so. There are ways to extend the life of some products but it's best to aim to use them in a timely manner and buy quantities that make sense to a given situation.

 

Have a look at my Legion Rising WIP p'log to find my personal insights into the resin casting process. The content is a bit scattered within the thread but it documents my experience with casting from my very first mould all the way to what I'm up to today.

[TURBULENCE]

Thank you for all of this, to help clarify how far I'm going with this, I feel I'll be more than likely to be in the 250+ price range. The project is not just for myself. But for me, it will be to replicate components like weapons helmets and backpacks, as well as the occasional vehicle component, right up to whole models. The other half of this project will be applied to non-40k uses. A family member of mine is in the RC aircraft hobby and he is wanting to cast his own custom components for his builds. Those will most likely be larger and more robust than what I plan to do.

[TURBULENCE]

Sorry to double post but I haven't been able to edit my posts recently for some reason. thank you everyone for all your help and links. And Subtle Discord I will certainly be reading through your work again, with your commitment to quality, I can think of a better person to learn from

[Subtle Discord]

Happy to help. Feel free to ask questions or request clarification. It really is up to you how far down the rabbit hole you want to go and how much time and funds you want to invest in the venture, but the way I look at it, for roughly the cost of an army of GW miniatures you can have equipment that will give you the ability to replicate almost thing you put your mind to. It will be up to you if there will be enough return on the investment you're willing to put in.

[lhg033]

Just to add another source of info Masteroftheforge has a number of tutorials on his site

https://masteroftheforge.com/category/moulds-and-casting/

 

This is the one that i had saved but there are several others good for a bit of guidance too

https://masteroftheforge.com/2011/12/02/mold-making-by-an-idiot/

[Ovidius Incertus]

 

One key thing to remember is that casting materials do have a shelf life; RTV rubber compounds will thicken and the 'A' compound of casting polyurethane will turn to 'slush' as it slowly reacts to the moisture in the atmosphere. If you want to go this route just be aware that you don't want these materials sitting around for longer than 12 months or so. There are ways to extend the life of some products but it's best to aim to use them in a timely manner and buy quantities that make sense to a given situation.

 

 

I'm aware of the shelf life, but does the shelf life apply to the materials still in their sealed containers, or just to containers that have been opened?

 

I got some two-part resin and RTV to make molds but then got back burnered, and my materials are now over a year old and I won't be able to get to them until the summer.  Packages have not been opened, save the mold-making clay.  Will they still be good?

[Major_Gilbear]

 

 

One key thing to remember is that casting materials do have a shelf life; RTV rubber compounds will thicken and the 'A' compound of casting polyurethane will turn to 'slush' as it slowly reacts to the moisture in the atmosphere. If you want to go this route just be aware that you don't want these materials sitting around for longer than 12 months or so. There are ways to extend the life of some products but it's best to aim to use them in a timely manner and buy quantities that make sense to a given situation.

 

 

I'm aware of the shelf life, but does the shelf life apply to the materials still in their sealed containers, or just to containers that have been opened?

 

I got some two-part resin and RTV to make molds but then got back burnered, and my materials are now over a year old and I won't be able to get to them until the summer.  Packages have not been opened, save the mold-making clay.  Will they still be good?

 

It also depends on how/where they were stored.

 

It can be hard to tell, but if they've been stored well and unopened, it'd be worth doing a little test a few days before you do your main casting. That way, you still have time to get some more for your project if it's gone off - but there's no point in getting more pre-emptively if you aren't going to use it for a few months yet.

 

The clay is fine though. :)

[Beaky Brigade]

 

 

I'm aware of the shelf life, but does the shelf life apply to the materials still in their sealed containers, or just to containers that have been opened?

 

I got some two-part resin and RTV to make molds but then got back burnered, and my materials are now over a year old and I won't be able to get to them until the summer. Packages have not been opened, save the mold-making clay. Will they still be good?

Only way to be sure is to test it, but it was quite obvious when my hardener went off, it set in the jug! It's possible it may look OK but not set right.