Polyurethane Resin??

If you don't want to go to the place that can provide the most information about sculpting and casting your own BJD because you don't like the colour of the site or its name, I have to wonder if you're actually serious about following through with this? Yes, ABJDs are cast in polyurethane resin but if you want to know what specific products to look for in casting your own doll I'm sorry to say that I can't help you since I've never made my own BJD.

I hope you can work out what to buy once when you get started on your doll, either with the help of The Joint's members or not.

 

well, i have to wonder if the people that created the site are serious about LIFE> nonetheless, i have been to that site and seen products such as alumilite and smooth-something, and i still reply to the threads.

 

I haven't read through all 8 pages, and sorry, I'm sure someone already mentioned this, but when I was working in the toy industry and first came across "resin", the biggest difference in that type of plastic compound is that is takes an incredible amount of detail from a mould. It was always referred to as Resin by the people who worked with it and it revolutionized the company I was working for at the time. We were suddenly able to design and create much more satisfying sculpted work... I'm not a chemist and don't understand how the particular types of plastic classed as resin do this but they just seem capable of stretching and filling every nook and cranny of the most detailed moulds, which is why "resin" BJDs have such beautifully detailed faces, fingers, etc...

A Barbie doesn't look that way because the sculptor was a bit rubbish at recreating human faces and figures... she looks that way because that's the best they can get out of the plastics used and the various processes used to mould her. I love the kind of dolls that declare their plasticity loud and proud as well as BJDs... Mass produced has it's charm too.

So that's not very technical but from my experience and frankly... yay for the plastics we call resin!

 

sure someone already mentioned that the type of plastic/resin is supurior when going for detials?

 

xscene_laura: The Joint is a great source of information - I am a member same name. If you wish to know any specifics about the materials you only have to ask. Though (and I say this in kindness) it may help if you remember that a lot of BJD and doll-related forums have cross over members (like myself) and it wont do to insult those from other forums here as you have a pretty good chance it'll be read and be offensive.

In a nut shell though: Ball Jointed dolls as defined by the members on this board are made from Polyurethane Resin (or PU Resin) whilst not stated by all companies its suitability to the hobby makes it an assumed material. Epoxy Resin is not suited to these types of dolls due to numerous restictions on its application so the likelihood of "accidentaly" buying an epoxy resin doll is nil - the same goes for polyester resin, it has a different chemistry to PU and its applications make it a difficult product entirely unsuitable for doll making.

Vinyl is a soft plastic polymer that can be made into as many varied products as PU resins can - it is the soft and flexible plastic used for childrens baby dolls, kewpie dolls and the bendable arms and legs of Barbies it is also the material all "american Girl" dolls are made from - it can also be a near rigid product such as Barbie's torso pieces, doll shoes etc... The main difference in PU and Vinyl apart from the chemical make-up is its applications - you cannout "pour" a vinyl doll - proper equipment is required as well as heat applications - injection molds etc... PU resin is mixed and poured to make the dolls refered to in this particular hobby...

I hope that my answer has been of some help otherwise - despite the lovely shade of green at the Joint it really is a better place for your technical questions and to get all the assistance you need to make your own doll

 

well, let me tell you this, someone in this thread threw me off by stating that all companyes use polyurethane epoxy, i have been using epoxy resin for jewelry and i didnt think it was related to the bjd resin.
i have to let you know though, i dont find the green pleasing for a reason...

 

When did I say all companies use epoxy resin? The "etc etc etc" in my first post was suppused to be a slightly humorous example of why we just say "resin" instead of technobabbling around and I honestly found your next post a bit difficult to understand, even after reading it twice.

Dolls are cast in polyurethane resin. Epoxy resin putty is often used for modifications on already cast dolls. If you want specific brand names and suppliers, The Joint is the best place to ask.

I'm sorry if I said something that misled you, but you may want to write your posts in a clearer (and perhaps friendlier) manner so that the members of this forum can understand easily what you are saying and asking.

 

"A rose by any other name would still smell as sweet."

I don't care what it's made of or what it's called as long as I can enjoy it. To be honest, I really don't understand the need to justify the value by calling it resin, because how someone else perceives my dolls holds very little relevance for me. If they want to call it a Barbie, let them. They can even say it's a worthless piece of crap. To them, it may be, but that won't define how I myself perceive it.

That aside, this thread has been an interesting read.

 

xscene_laura, it's really hard to understand your posts but from what I can interpret, you're asking for help and information. Are you aware that you are also being rather rude while you are asking for this information? And not just in this thread either.

We were all new here once. We didn't buy a doll and instantaneously get filled with knowledge on what the dolls are made of. Do your reading and research; not demand answers to be dropped into your lap while getting huffy about how you shouldn't be expected to know anything cause you're new. The forum members are always here to help and sometimes, make things easier for you, but we're not here to be your punching bag and personal answer man.

 

I am actually quite amazed at skwerlie 's patience and kindly manner.

 

It does not bother me in the slightest to call all these dolls plastic, because they are plastic, but the purist in me does wince a little at people saying they are made of resin, rather than the technically correct from resins. But that is really splitting hairs. Here's my full explanation:

Historically, resin is the sticky hydrocarbon stuff that oozes from trees, most notably conifers. Pine tree resin actually provides components for some so-called "french resin" materials, IIRC. As plastic technology evolved, people started applying the term resin to the chemical precursors that combine to make thermoset plastics, because of the similarities between how thermoset plastics go from liquid to solid, and how tree resin becomes amber through polymerization over (lots of) time.

Polyurethane is a thermoset plastic made from reacting diisocyanate compounds with poly-alcohols (polyols) which are alcohols with more than one -OH group, required in order to form polymers. The resin used to make most ball-jointed dolls starts out as MDI (4-4' Methylene Diphenyl Diisocyanate) and a mixture of polyether polyols. These materials react quickly to form semi-rigid polyurethane elastomers. All different types of polyurethanes can be made depending on the choice of diisocyanate and polyol. MDI-based aromatic polyurethanes cure very quickly (some in a few minutes), enabling fast production, but have the downside of breaking down and yellowing under UV light (sun) and being less strong than polyurethanes made with aliphatic diisocyanates. But aliphatic polyurethanes take too long to cure for practical doll production, are more finicky to cast, and the aliphatic diisocyanate precursors also have more toxicity issues.

The end result of the two resin components reacting, polymerizing and crosslinking is polyurethane plastic. Plastic is a very general term for solids made from hydrocarbon polymers. Polyurethane is just one type of plastic, from the thermoset family (plastics made from reacting two or more prepolymer materials) which also includes epoxies and some polyesters. Thermosets ultimately crosslink into one big molecule, and can't usually be melted down and reshaped.

The other major family of plastics are the thermoplastics, which are the kind that are mostly long-chain molecules without crosslinking (usually). Thermoplastics can be melted to a liquid and remolded over and over. This family includes PVC (polyvinyl chloride), styrene, polyethylene, polypropylene and ABS which is a co-polymer of three other thermoplastics, acrylonitrile and poly-butadiene and styrene. What we normally think of as mass-produced, injection-molded dolls like Barbie, Momoko, etc... are a mix of hard PVC, soft plasticized PVC "vinyl" and rigid ABS parts.

Dolls made from polyurethane resin are usually made by mixing the resin components and pouring them into silicone molds that were made from a master model (which could be made of just about any sculpting medium, or a first generation resin casting). The silicone used to make the doll molds also starts out as 2 or 3 things mixed together, known as a room-temperature-vulcanizing rubber, or RTV. Usually, it's a tin-catalyzed 2-part silicone.

Dolls made from thermoplastics have their parts formed by injecting melted plastic into steel molds. The molds themselves are usually made from some combination of machining by computer-aided mills (CNC machines), or by electrical discharge machining (imagine a copper doll body literally sparking and burning itself into a block of steel by having a large electrical current put through the parts).

 

xscene_laura, I'm sorry, but I think you are getting off topic. The point it to debate why the community cares so much about saying their doll is made of resin as opposed to plastic (even though resin is plastic) - not to figure out what material to make your doll in. If you need information about types of materials you should just go to The Joint. If it is not already posted someone will surely answer. The people there kindly give up their information for free and it seems very arrogant to insult them (especially since even some of our moderators here are participating members there as well). If you don't like the site then try to figure it out on your own. It wasn't too long ago that it was near impossible to find any information on this kind of stuff and we all had to spend a lot of time scraping up any info we could find. But to ignore a great resource just because of the name and color of the site just seems ignorant. Sorry to be so defensive.

Edit: Beautiful, informative post, Adam! ^_^

 

Looks like all her (xscene_laura) posts were deleted....

Neat reply Adam I love that there are so many articulate yet awesomely cool nerdies here (ok so I'm not THAT cool but getting there LMAO)

 

I'm new to the BJD community and am wondering what advantage polyurethane resin has over other materials such as vinyl.

From what I've read polyurethane resin tends to turn yellow and decay over time depending on exposure to UV light and heat, and sanded dolls will yellow faster unless protected by a uv sealant.

Also, resin and it's dust are toxic, it is more fragile than vinyl, the materials are more expensive, and the process requires more manual labor.

Many collectors say resin is higher quality, but in what way?

 

Making dolls in vinyl would take a factory. It costs a lot of money to get all the machines set up to make vinyl parts, so it would only be worth it if one was to really mass produce the dolls. Most doll companies are a small group of artists as opposed to are large company that don't have the resources to make vinyl parts. Especially since these dolls have a lot more intricate parts than, say, Barbie. The shape would also be limited since you couldn't have any undercuts because of the way vinyl is cast, and you can't get the same amount of detail you can with resin.

Yes, polyurethane resin does yellow, but it isn't that bad with a high quality resin. Sanding does not cause it to yellow faster.

Resin dust is not toxic. It is what it is - dust. Any dust it bad, but what makes resin dust extra bad is that it doesn't decompose and will just stay in your lungs. If you had dust from vinyl you would have the same issue. And, resin isn't exactly fragile. It really depends on the specific resin you are using.

One of the benefits of resin is that you can sand it and modify it. This way you can remove seemliness or mod it as much as you want the way you can't with vinyl. I think resin is also nicer to paint, especially with pastels, and you can remove it and start over easily.. but not easily enough that the paint will just come off on its own if it is properly put on.

Resin just looks a lot nicer then vinyl. There is just a different quality to the surface. It is not hard to see the difference if you put a ball joint doll next to a mass produced toy.

 

firefly5003, it's quite well documented that polyurethane resin dust is toxic. Yes, any amount of inert dust can make you ill if you inhale a lot of it, but resin dust inhalation can truly be nasty to your airways and make you seriously ill, particularly if you have an underlying respiratory condition anyway like CF or asthma. It is always important to wear a respirator when sanding your doll and almost always preferable to wet sand resin outdoors, so that the dust doesn't fly everywhere and settle inside your house where you could breathe it in later or your pets could inhale it. It's important not to ingest resin either, and if a pet accidentally swallows a part of a BJD, e.g. by nibbling on a hand, take them to the vet immediately.

It's important not to play down the toxicity of this material when so many hobbyists will be wanting to modify their dolls in some way. It's not worth acquiring permanent lung damage because you sanded your doll without a respirator. This also goes for spraying MSC or other sealants without masks on -- value your personal safety and keep yourself healthy first. If you can't or don't want to take these steps, I urge you to pay someone else to do these mods for you. I know someone with severe emphysema and it is horrible watching this person fight for breath, I myself have asthma and have to be careful with my airways. Struggling to breathe is frightening. Avoiding breathing in resin dust is easy.

Adam, thank you for your very informative post, I really enjoy learning about the technical side of casting.

 

Resin dust is not toxic the way most people define toxic. I guess if you have a broad definition of toxic you could consider it but then almost anything could, in theory, be toxic. A lot of people think fumes are released when sanding or the material itself is toxic and that isn't true. The reason the dust is bad is because if you breathe it in it will stay in your lungs. And you could develop a allergic reaction to it, but people develop allergic reactions to many things that are no toxic. I am not saying it should be taken lightly or that you shouldn't be careful but it isn't the toxicity that is a problem - most paint is more toxic than resin (cured resin, that is). The fumes released when resin is heated up are toxic, as your link suggested, but a lot of things release toxic fumes when heated - which is why you aren't supposed to reuse plastic utensils by putting them in the dish washer or cook sculpture at a higher temperature than recommended.

 

I guess it's when people state that it's plastic- the mental image that it invokes is the mass produced kind of toys and it kind of leads a false lead on if you call a BJD that since it's not a mass produced product like other toys are. I know that resin is a kind of plastic but to a regular Joe Schmo who really hasn't an idea of what a BJD is or would be immediately alarmed at the composition + pricing of the doll would have a 'negative' attitude or belief that you overpaid for something that's considered 'mass produced' like other plastic toys are. However the minute you mention the word 'resin' their interest is piqued and they're not as harsh to judge and are more likely to ask the process behind the creation of the BJDs which is much different than mass produced dolls.

 

Anotrhering concerning the term "Plastic" vs. "Resin" is the meathod of casting. Plastic, generally speaking, is poured into molds, similar to bronze or aluminum in an investment, whereas comercial BJDS are usually made with injected resin molds - very different from the plastic - pour molds. This does not mean that artist - made BJDS are any less resin-tastic , is means they are simply made with a different meathod.

 

When I hear the word plastic versus resin, I think of a certain texture, price and staining.

Resin is a pretty porous plastic (hence its used in chromatography for chemical laboratories), where as some others are not. This is why BJD owners worry about staining.

The items I think of when I hear"plastic" are not as porous. They tend to be slick, shiny and disposable. Not words many want associated with a BJD right?

For example, the plastic on my 2.3 cent mass manufactured cheap-o pen would be hard pressed to stain, and for good reason! Or how about food containers? Would you want a porous food container? Personally, I wouldn't just knowing that "Porous food container" can translate to "you'll be tasting that fish you stored in me for weeks no matter how much you wash me!".

I digress back to my original thought, resin makes my mind conjure images of "special" plastic. This goes along with the expensive nature of the hobby to create (for me at least) that oh so lovely "why yes, my BJD kicks the snot out of your Barbie. Mine's CUSTOM and SPECIAL" hype. As far as I'm concerned, it allows me a little more leverage to explain to my friends and family why I spent so much money on a doll. (Except my mother the chemist who asked me if I was going to use her for filtration experiments. )

So, plastic versus resin? For me, it's all about the texture and quality. (And I'm a quality snob.)