Help with Resin Casting my Deathstroke Mask

Ironstorm

New Member
Hey there, so I've been trying to do some research on how to make a mould that will work as far as resin casting (or any casting for that matter, I'm not set on it having to be resin).
I have finished my sculpt and am just waiting for it to dry. I used water based potters clay (or terra cotta) and plan on sealing it with some Krylon Acrylic Clear gloss a few times.
After that, my plan was just to directly use plaster of paris on the mask, but I see some places telling me not to do that, but to use dental alginate which I think I could get my hands on as well.
I have a few questions though that I hope some people can answer.
1.) What would be the best thing to use as a cast that is cheap? Will plaster of paris work just fine?
2.) What are my options as far as materials to cast with? Is resin the only real option? Or can I use paper mache or something else?
3.) If I do use resin, can I sand it to get it really smooth?
Any other tips you could suggest that would help me would be really excellent, cheers!
-Stormy
My sculpt so far (still drying) imgur: the simple image sharer
Desired result (as close as possible) http://www.gonnageek.com/wp-content...otMoreStarInFirstBatmanArkhamOriginsT224.jpeg
 
Hi there ironstorm, and welcome to the RPF :)

From the looks of the referance pic, its a type of solid mask/helmet (not totally sure as I can't see the back of the character's head). If this is the case, plaster of any kind alone is not a good idea when casting resins as separating cast and mould can lead to all sorts of disasters. Common practice is to make a silicone "skin" layer between the master sculpt and hard outer mould to both capture fine detail in sculptures, and to aid easy demoulding.

Of note, there are two main types of RTV (Room Temperature Vulcanising) silicone:

Tin/condensation cure (a general purpose silicone thats not too difficult for the novice to use, and platinum cure (superior quality, professional silicone that is able to deal with a wide range of uses as it's food/skin safe, has high heat and chemical resilience properties and makes long lasting moulds and this can be reflected in it's price depending on the specific type. Platinum cure is also a total diva though and just won't work if certain chemicals/minerals are present so extra precautions are needed when using it.

If your US based, www.Smooth-On seems the popular choice for mould making on this forum as they have quite a wide range which seems to be good quality, though all products only come in two options, trial size (anywhere between .800-1.5kg depending on product), or much larger quantities (5 gallon units or higher).


Look up Volpin's Daft Punk helmet build for inspiration and technical references (any of his work is top notch). Smooth-On's website also has a vast library of mould making tutorials and how to's (including Volpin's helmet moulding process) that is worth a look or two.


If your UK based, Fibreglass Supplies | Silicone Moulding Rubber | Casting and Polyester Resins - mbfg.co.uk is a great place to start for materials, very helpfull and friendly staff, good range of products for pro's and the budget minded :thumbsup

The official Smooth-On distributer for the UK is Mould Making and Casting Supplies from Bentley Advanced Materials.

As to casting materials, there are plenty of options to choose from, but for practical prrposes I'd stick with either fibreglassing or two componant polyurethane resins. Stick to Polytek EasyFlo120 (from MBFG), or Smooth-On's 65D or 300, all can be sanded and are tough resins when cured (I recommend a thicknes of at least 2mm for masks and helmets as it aids durability and prevents them from flexing.

Hope that goes some way to helping you out a bit, just post here if you need more in depth info or processes explained ;)
 
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I'll second most of that, you don't want to use plaster to make a mould for anything, unless you're planning on casting your finished product in latex. Even then there are better options. Is this a mask that you're planning on being able to wear?

Alginate is not great for casting resin into, as the water that you mix with the alginate powder will react badly with any curing resin. Not saying it won't work, but it won't work well.

Pretty much any resin you choose will be good in terms of sanding to a smooth surface, though some are harder than others. Smooth-on's tutorials are excellent.
 
Amazing responses so far guys thank you very much. I have been doing a lot of research and really feel overwhelmed by the amount of information that is almost what I need but not quite as far as how to cast a helmet. The reason I wanted to go with alginate is just because of how cheap it is. My local dentist is selling me a kilo for 10$ CAN, so. The mask itself in the photo has a fibreglass look to it that I was going to replicate with a paint job, but do you guys think it would be possible to cast it with real fibreglass using the alginate? I kind of have my heart set on the alginate price wise, but of course if it's simply not going to give me a good result I will use the silicone.

I might do a trial run with the smooth-on, see how it goes. Trouble is finding it in Canada. The other thing I'm kind of struggling with at the moment is how to make the cast itself, it seems way more complicated than I thought with all these key holes and plugs to stop the resin from escaping during curing. I'm just trying to get a decent result but not have it super complicated as it is my first cast...any other tips you guys have about any of the process would be really really welcome. I will try to post my progress. Ty for taking time out of your lives to help a brother out.
 
I am doing some research on an eco friendly casting agent called Jesmonite, as it is water based, I think it will react better with the Alginate, and it is cheap as dirt. Either of you have any experience with it?
 
Jesmonite into an alginate mould is actually a good idea, as like you say, it is water based. Things you should be aware of with alginate: Once set, it has a limited shelf life as a mould. Don't expect it to last more than a couple of days before starting to dry out, shrink, and crack. You're unlikely to get more than one or two casts from it. You must mix it with a drill or other mechanical mixer, or it will stay quite lumpy, and this will be reflected in the mould. Finally, you have to pour the mould all in one go, as once it sets, a new layer of alginate will not bond to the first layer, and you'll simply end up peeling layers of alginate from your sculpt.

Personally I find alginate more trouble than it's worth, but as a cheap learning experience, you could do worse. I have to say I didn't much like jesmonite either, but again as a way of learning to cast, you could do much worse. It remains quite brittle until fully cured, so bear that in mind when demoulding it.
 
Thanks Uridium, great economic way to make a silicone mould, I will look into that when I get a bit more experienced. Alginate seems like a cheap easy way to screw up a few times. Bookface thanks for the great responses. You have preemptivley answered all of my questions as they arise. I come on here to ask it and you have already posted an answer before I need to ask, thanks so much! I will eventually move into the realm of casting properly, but as this is just a christmas present of my little brother, I'm okay for now using Alginate as 1 shot mould and the Jesmonite seems like a non-toxic cheap way to get a fairly good result. I will take some videos and photos of the process and post them here at some point so you guys can send some more pointers.

I did a test cast on a shotgun shell and found the mould dried out within about a day and a half, I also found that the plaster shell I made around it didn't dry properly, I thought perhaps because of the wet-nature of the Alginate? Perhaps I just used the plaster strips wrong...I am worried about that for my main project mould so I think I will hairdry it.
 
Sorry this took so long to update, but here is the first draft of my mask. I had some issues with the Jesmonite/Aquaresin cracking in certain places because it is remarkably brittle for the first few days until it completley cures. As a result, I will be making another an not being impatient.


imgur: the simple image sharer IMG_0590.jpgIMG_0574.jpgIMG_0571.jpgIMG_0570.jpgIMG_0559.JPG
 
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