mold casting matl's

  1. #1

    mold casting matl's

    I was looking around the net for something other than, fiberglass to make my bucket with.

    I found this site what do you think?

    http://www.smoothonsecure.com/

    Given my dome will be made from plastic, I figured making the rest would be a plus as well. Plus I think it would be much lighter and lot less messy.

    Any ideas? Im not looking to make tons of mold castings here, just make one helmet. At least for now.

    This is my first casting project, and help would be great!

    DM

  2. #2
    Michigan Jaster's Avatar
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    Re: mold casting matl's

    I'm just venturing into mold making and resin casting myself. I'm elbows deep into my Jaster Mereel project. Personally, I find that I prefer a platinum curing 2 part silicone made by Smooth On called Dragon Skin. You can stretch it up to 10 times it's size without tearing or warpage. It's also easy to mix, no scale needed it's a 1:1 mix. You can find a lot of products for a decent price at this place www.tfbplastics.com

  3. #3

    Re: mold casting matl's

    I found this stuff last night at napa, when I was getting motor oil. Its made of microfine particles of aluminum, suspended in a resin matrix. When it cures it cure into what looks like a solid aluminum piece. I thought it would be nice for a jango helmet. I didnt get it when I started thinking about attaching the plastic batting helmet to the rest of the mask. but it looked like it would be pretty cool looking when cured.

    Sorry I dont have the name of it handy. If I see it again i will post it here.

  4. #4
    evan4218's Avatar
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    Re: mold casting matl's

    Resin works well and is often times easier to use and less messy then fiberglassing. I recommend using Smoothons Smoothcast 300. Do it slush cast style. Basically you just pour a small cup of resin into your mold and slush it around till it makes a thin coating and once the resin starts to thicken you pour it out and then repeat untill you build up a thickness that suits you. This is how the Sgn Fang buckets are done. You can also add pigments to this as well.

  5. #5
    Stormrider's Avatar
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    Re: mold casting matl's

    I know, thread of the dead, but im just about to be at the stage to cast my variant, so a quick question for evan or anyone else thats doing a lot of casting.

    If you slush cast it, say to about 1/8 - 1/3 of an inch thick, how durable is it? Or do you need to fiberglass it? And will fiberglass stick to the smoothcast 300 well?

    I didnt know you were supposed to poor it out once it got thick. Though it makes sense.

    How long should you want in between coats?

    Thanks again.

  6. #6
    Darth Clouds's Avatar
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    Re: mold casting matl's

    evan4218 said: View Post
    Do it slush cast style. Basically you just pour a small cup of resin into your mold and slush it around till it makes a thin coating and once the resin starts to thicken you pour it out
    Hi,

    I have tried casting two decades ago for the fun of it and has stopped my hobby for a long time, I used alumalite. Now I just got back into it again, and is the first time I came across slush casting, I am thinking of starting a project using the slush cast method. But I do not understand what you mean by "once the resin starts to thicken you pour it out". Do you pour the excess out from the mould?

    Peace

  7. #7
    Stormrider's Avatar
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    Re: mold casting matl's

    Well aparently, as you rotate it around, for the 3 minutes, small amounts will stick and start to harden. But at some point it will start to thicken rather fast.

    When that starts to happen, you just poor it out because its too thick to coat evenly.

    This is the way I understand it, though I havent done it.

    Im hesitant to try, without having a firm grasp on what im trying to do, however, it doesnt appear you can do too much harm, except waste materials.

    Im going to be making a cast of a custom helmet I created. Im raising my helmet up off the deck about 2 inches, so that when I slush cast it, ill be able to get all the way to the helmet base. Im still a little confused and concerned about how to do it, and am hoping to get a little more insight before I start.

  8. #8
    Darth Clouds's Avatar
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    Re: mold casting matl's

    Well, I tried today with some alumalite resin in an attempt to cover the internal surface of a fiberglass lid to prevent fiberglass particles from contacting the face or hair.

    But when the hardening process began, I found that it is quite impossible to pour the excess out. It is very much like lava and it solidifies real quick. I will have to sand it even, but it is at least safe to sand resin than fiberglass IMO.

    Good luck to your endeavour though.

  9. #9
    Stormrider's Avatar
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    Re: mold casting matl's

    Maybe its a matter of timing it and knowing how much longer you have. Again, that was my fear

    The other alternative for me is to spray it with gelcoat, then fiberglass it. But theres so much cleanup involved in that, its not funny.

    I cant find a tutorial where someoen shows the process anywhere.

    But ill keep looking.

  10. #10
    Darth Clouds's Avatar
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    Re: mold casting matl's

    You can try youtube and searh under helmet mould making. I found one where they made a Halo Master Chief helmet but they skipped several steps. But I do not remember them pouring out the excess resin.

    Peace

  11. #11

    Re: mold casting matl's

    Actually, the way Sgt Fang does his helmets is with expanding urethane foam. One application will expand multiple times it's poured in thickness depending on which you use. With two good slush's, you get a pretty sturdy piece. Saves materials too. With SC 300, you may end up slushing 6 coats or more to get the same desired thickness. Although, the SC 300 is more durable. The Sgt fang buckets have been known to crack or break when dropped.

    There is also SC 300 Roto. Which is supposed to be designed for slush/roto cast applications. They call it self skinning. But it's a scam IMO. I've used it, and it doesn't do much better than SC 300 as far as material conservation. The main difference is that it's a little bit more flexible than SC 300 when cured.

    If you want an inexpensive piece, try the expanding urethane foam. It's called Smooth-On "Foam-it". Sgt. Fang may not use the same brand, but it's the very same concept. And they have different types in that series with different properties that can suit a variety of needs. I've actually considered doing the FPH's in this to offer a more cost effective alternative to those on a budget. Still toying with the idea actually. it also plays well in cold weather, whereas fiberglass and gel coat - not so much


    Stormrider said: View Post

    The other alternative for me is to spray it with gelcoat, then fiberglass it.
    Uhm, I wouldn't go to that extreme. Spraying in your gel coat layer is good for LARGE molds, like an auto body fender or boat hull. For small props, including helmets, the "brush-in" method is much more reasonable, and disposable. Unwaxed dixie cups, popsicle sticks, and 1 inch natural hair bristle brushes (79 cents each at home depot if you're not doing large production)


    Stormrider said: View Post
    will fiberglass stick to the smoothcast 300 well?

    Personally, I think it is worthless, and a waste of money to laminate SC 300. Granted, people do it all the time, with varying results.
    But SC 300 is a urethane. Fiberglass is polyester. They will only stick together temporarily I gaurantee that you will get de-lamination
    at some point (separation between the two), especially when it gets real humid.

    Stormrider said: View Post
    But theres so much cleanup involved in that, its not funny.
    That's sooooo true, it's not funny




    FP
    Last edited by fettpride; Feb 8, 2008 at 7:35 PM.

  12. #12

    Re: mold casting matl's

    fettpride said: View Post
    I've actually considered doing the FPH's in this to offer a more cost effective alternative to those on a budget.
    oooh, that sounds like a great idea. i'd love to have an ESB display helmet. i want it to look good, but i'm not really worried about durability, since it will sit in a case forever.

    so um... you've got my vote!

  13. #13
    SinisterFett's Avatar
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    Re: mold casting matl's

    I've done alot of slush casting in the past making Predator Bios. Although I've never poured out the resin once it starts to thicken, mainly because you can't. What I do is that when the resin refuses to move I smooth out any lumps with my latex gloved finger. This works fine and stops the interior of your lid looking like the surface of the moon.
    As for casting material. I use Biresin G-26. It's a 1:1 mix and is non toxic, although is an irritant so avoid skin contact. I've also used fibreglass matting with it and had no de-lamination problems. This stuff is idiot proof, has great detail pick up and little to no air bubble retention in the casts. Oh and did I mention that it's cheap too. If you're going to get into casting stuff I'd reccomend this without hesitation.

  14. #14

    Re: mold casting matl's

    I'm in the middle of a run of Halo helmets using this exact same method.

    The trick is, using a bit of trial and error, you will eventually figure out how much resin you need to pour into the helmet so that there is no excess to pour out and waste. For example, the helmets I'm making are rather large and I'm mixing batches of about 8ounces of liquid resin per layer. I end up putting in four to six layers to build thickness and, depending on what I add to the batches of resin, the final castings will end up as much as 1/4" to 3/8" thick. I wouldn't want to play football in these things, but they do hold up to a reasonable amount of abuse.

    Also, look into what're called "thixotropic" additives that make the resin a little more viscous. That way, you can build thicker coats each time you pour. I usually add microballoons to the first layer to make an easy-to-sand surface and then mix in silicates or glassfiber in the next few layers for strength.

    There will be some irregularities inside where the resin cures in drips or rivulets (or full formations of stalagmites and stalagtites), but they can be easily fixed with a dremel tool or an angle grinder with a flapwheel sanding disk. Here's the best pic I've got of the inner surface of one of my castings:



    Before anyone asks, here's a shot of the outside of the same helmet:


  15. #15
    Stormrider's Avatar
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    Re: mold casting matl's

    Thanks for all of the info.

    So let me try to sum this up, and get the 'difinitive suggestions'.

    Smoothcast 300 is great, but its an 'ultra low' viscosity, so its not going to be doing much each coat.

    Smoothcast roto, is also goo, but a bit thicker, and supposedly 'self skinning' and its flexible. Too flexible for a helmet in the heat?

    The 'foams' are in weights of 3-15 lb per cubic foot i believe. Meaning that the light 3 lb, is like post hole filler/sealant foam. And the 15 lb is a rock, and much denser. Is the 10-15 lb smoothon foam what is similar to the sgt fang?

    As for thixotropics, I dont see any on the smoothon site. Im thinking Im going to use rebound 25 as evan suggested months ago to me, as my mold material, similar to the way FP did his helmet mold (though not nearly as well done) and cast it in smoothon 300, roto, or foam.

    I dont mind the rigid foams, as long as they allow for a nice paint coat.

    What are the FP helms done in? Gelcoat with fiberglass backing?

    Ive painted on gelcoat in college, but never tried painting it. Can you use a brush to get a paint coat with gelcoat?

    You know, we have all these masters of mold making around here, id LOVE to see a thorough tutorial on this. Because some of us work on such a tight budget that id hate to throw money into the wind without any gratification

    Thanks again in advance.

  16. #16

    Re: mold casting matl's

    The SC Roto isn't really flexible per say. The shore hardness rating on it is a bit less than regular SC 300. They told me that it's a little "softer" (not much) to allow for "some" flex in the finished casting depending on it's cast thickness. If it's a thinner casting like 1/4 inch thick, or 1/8 th inch thick, it will flex a little farther than a casting of the same done in SC 300 before it ultimately "snaps". So the simple answer is, it is rigid, and strong enough for a helmet

    I have traditionally done my helmets in FG. But I have to say, given that I've been at a dead stand still on those because of weather, and the ill effects it has on one's health ...

    I might as well publicly say right here and now since we're "on topic" ... FG is just archaic. It's gone up in price, and well, it just makes me sick anymore. And it takes 10 times longer to set and cure. I'm about done with it It has it's place, sure. And there are some things you just have to do in FG. But all in all, technology in plastics and polymers, or casting materials in general have advanced so far, that there really isn't a need for us "old time fiberglass lay-up guys" to continue killing their brain cells on styrene fumes (polyester resin) So I've officially decided to offer things like helmets in a different medium. Again though, FG has it's place, like on a more complex piece like a DV helmet. But in general, I've found a casting material that is rigid, and virtually unbreakable that would suit this area perfectly. It's cheaper than the FG process when you add it up dollar for dollar including time. I'm not going to blow smoke about what it is just yet, until I know for sure. In a case like this, it's almost a wee bit of a trade secret, because once the trend is started, there will surely be others to follow suit, so I hope you understand. I just thought this might be a good opportunity to "let the cat out of the bag" that FG and me ... are officially getting a divorce, and I will have "visiting rights" when it is absolutely neccessary

    The expanding foams - I think the Sgt. fang helmets are actually done in 8 lb. And there is no such thing as shore hardness with expanding flexible urethanes. That rating is essentially how many times it will expand over it's poured in thickness during the curing process. And it's cellular structure. The simple of it is - the fewer times it expands, the smaller the cells are (air pockets), the more rigid it is. The more it expands, the larger the cells are, and the cells are what create the "flex" in the structure when cure - on a molecular level. The more cells, the more flex .. until you reach "nerf" Hope that makes some sense


    The rebound 25 - I actually started THAT trend too If that's what you're going to use, you won't need the thixotropic. Or at least, I wouldn't recommend it. It's pretty fast setting, and is designed for brush on vertical application. I've actually had to use their silicone "thinner" at times. Great stuff. Just keep in mind, you only need about 4-6 painted on layers with that stuff. It's thick, but it you put it on too thick, it excess will still ultimately slide off. Even with a thickener. It's silicone, it slippery Basically, use only what you need, per layer and you'll be just fine.


    Tutorials? I've had the best intentions on that for years. The problem is simply - TIME. It just takes so long to make a good tutorial when it comes to something complex in nature like this

    FP




    Stormrider said: View Post
    Thanks for all of the info.

    So let me try to sum this up, and get the 'difinitive suggestions'.

    Smoothcast 300 is great, but its an 'ultra low' viscosity, so its not going to be doing much each coat.

    Smoothcast roto, is also goo, but a bit thicker, and supposedly 'self skinning' and its flexible. Too flexible for a helmet in the heat?

    The 'foams' are in weights of 3-15 lb per cubic foot i believe. Meaning that the light 3 lb, is like post hole filler/sealant foam. And the 15 lb is a rock, and much denser. Is the 10-15 lb smoothon foam what is similar to the sgt fang?

    As for thixotropics, I dont see any on the smoothon site. Im thinking Im going to use rebound 25 as evan suggested months ago to me, as my mold material, similar to the way FP did his helmet mold (though not nearly as well done) and cast it in smoothon 300, roto, or foam.

    I dont mind the rigid foams, as long as they allow for a nice paint coat.

    What are the FP helms done in? Gelcoat with fiberglass backing?

    Ive painted on gelcoat in college, but never tried painting it. Can you use a brush to get a paint coat with gelcoat?

    You know, we have all these masters of mold making around here, id LOVE to see a thorough tutorial on this. Because some of us work on such a tight budget that id hate to throw money into the wind without any gratification

    Thanks again in advance.
    Last edited by fettpride; Feb 12, 2008 at 4:05 PM.

  17. #17
    Stormrider's Avatar
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    Re: mold casting matl's

    Thanks man. Much appreciated.

    Ill order the rebound and the roto I think. Maybe a trial of the foam. Heck, maybe ill make a full plug out of the foam, and it will be easy to .... err hack up and destroy?

    Heres a silly question. If you use a non hardening clay, and try to mold off of the sculpt what happens?

    The thing is, im such a geek. Thats all. Thats the thing.

    I just want, no have, to try everything in life. Im this crazy mix of OCD, and ADD. Im compulsive till I figure something out, and feel like i get pretty good at it, then I move on to something else as if it never existed. The only reason I even do web/programming anymore is because it allows me to buy toys.

    Im also half tempted to try the aluminum filled resin they have at smoothon. (Notice the ADD flip?)

  18. #18

    Re: mold casting matl's

    Stormrider said: View Post
    Thanks man. Much appreciated.

    I just want, no have, to try everything in life. Im this crazy mix of OCD, and ADD. Im compulsive till I figure something out, and feel like i get pretty good at it, then I move on to something else as if it never existed.
    I can sympathize. I get on a point of interest and learn like everything I can on that subject. Problem is it's usually not very marketable stuff. IE: I know way more about ALIEN and H.R. Gieger and Akira Kurosawa and Japanese films than most people I run into. It's just not very useful, even in Trivial Pursuit.

    If you do that with enough related subjects, you'll have experience on a subject and end up with a career instead of just a J-O-B.

    I've heard that if you read three non-fiction books on a specific subject and you will be WAY ahead of everyone else on that subject.

    My problem is I don't like non-fiction.

  19. #19

    Re: mold casting matl's

    Molding off of non -hardening clay - just be careful of your silicone compatibility. Some silicones (both platinum and tin cure) will stay sticky anywhere it comes in contact with some clays like that. Even clays with sulfur in them. In cases like that you need a barrier coating of acrylic lacquer or something to that nature. Release agent simply won't work.

    Since you're doing some stuff for me, shoot me your addy, and I'll send you an unopened trial kit of the SC Roto. I won't be using it, so it will just go to waste if I don't do something with it anyway.

    Be careful of their aluminum filled resin ... It's not for what you might think it's for

    FP
    Last edited by fettpride; Feb 13, 2008 at 7:08 AM.

  20. #20
    BOBA PHAT's Avatar
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    Re: mold casting matl's

    I too have been trying to get fiberglass out of my life. Not only is it toxic, but it can be really tricky. I keep getting crazing and warping, not to mention anything curved like a shoulder bell will usually straighten itself out in FG. So far I've tried SC 300 and SC colormatch with various fillers to thicken it up. The casts come out beautiful, but I'm still looking for some strength. Backing with FG and polyester is OK, but only if the piece is under glass. Any bend or bump can crack it. A FG backing laminated with another urethane looks promising. SC 300 cures too fast to penetrate all the FG, leaving air pockets, but I'll soon try it the slower setting SC 310. I also tried out SC Shell Shock, which lays in beautiful, but is VERY BRITTLE!

  21. #21

    Re: mold casting matl's

    I found this thread at the right time. I spent most of last year making masters for some Fett stuff for multiple suits for myself and a friend. I wanted my own gear this time around and using Allen's templates and my years here I built the helmet, jet pack, guantlets, and some armor parts. I plan on posting all this at later time with pics and more info on it, as well as the many thanks other members here deserve for all the advice they give out daily.

    I'm really not wanting to do to much in fiberglass because I've had bad experiences with it in the past trying to salvage a buddies jet pack for him. So I'll be doing more research now in alternatives to FG.

    FP brought up Rebound 25 and that is what I've been planning on using for mold making. My concern has been about how much silicone would be required for the helmet (in the 1 gallon kits)? And pretty much the same question for the resin 1 gallon kits for slush casting 1 helmet.

    I've casted some small hobby parts before with random resins but haven't decided on what to use for the final stuff. Been looking at the C-1515 and C-1520 from smoothon but have no idea how they compare. I'll probably end up getting trial kits of a bunch of different products and experimenting some.

    FP's comment on the aluminum filled resin got me a little worried because I was planning to use that for some parts. What should that not be used for and any info on the metal powders?

    Just waiting for the weather to get a little warmer first.

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