Greetings Forum Members, Recently I've been looking into replicating certain parts for an Infinity project of mine. Mainly to create multiples of a torso and legs from different units & combine them together. I have been trying to do this with Blue Stuff or Thermoplastic but haven't had much success so far. I'm looking into creating resin molds as well but I wonder if I'm using the Thermoplastic wrong? Pressing down onto the miniature hard thinning the part that has the indent of the sculpt. How do you modelers use Thermoplastic to great effect? Is resin molds better and how hard, expensive & time consuming are they? Are the results much better compared to molds made from Thermoplastic? Please give some responses as I currently feel like I'm hitting a wall and not breaking through. Thank you in advance to any and all who comment on this thread.
The resin molds will always be better and have sharper details than thermoplastic/ colourstuff made parts. It's not that expensive and complicated but I guess it'sa bit more time consuming as you need to wait for molds (few hours*) and resin casts (few minutes*) to harden. (*depends on the resin and silicon you will use) I did my share of home made casting in the past so I think the quality is worth the effort. Nowadays when I need some parts I have them done as a commission, so you might try to find a local caster as well.
For simple press-detail (like adding a pistol holster somewhere), GS or thermoplastic molds will work fine. But for bigger pieces or better detail, you really do need to go to resin casts. And that will take some practice.
That makes alot of sense. Guess I'll head over to Hobby Lobby or a similar store and see what they got. Do you have any suggestions on what I should buy first? I was thinking of purchasing one of those "starter sets" which come with everything needed to make a certain amount.
Most important: check the dates on the stuff, resin gets finnicky to work with when it gets old. Next, read and get all the tools. gloves, wax-free paper mixing tubs, VOC (oil paint) rated respirator, safety goggles, EVERYTHING on the list. Wear clothes that you are willing to throw away when mixing this stuff, and don't mix it over or around stuff you care about permanently damaging (one or two of those big disposable aluminum roasting pans is perfect, but you're going to want to put down some sheet plastic dropcloth, too.). Otherwise, pay EXACT attention to the mixing ratios for both RTV (molds) and resin. Getting a little bit off in those (especially the mixes that are like 10:1 resin:hardener) can have NASTY consequences: Too much resin, it may never harden. That sucks, scrap the mold and make a new one. But it's not going to kill you. Too much hardener, however, and you will get what's called an "exotherm" (an exothermic reaction, a reaction that gets hotter as it works, works faster as it gets hotter, and so on, in a potentially deadly doom-spiral) of sticks-to-everything gunk that catches on fire. Napalm, but with even more toxic smoke to ruin everyone's day. And you cannot put it out, just wait for it to burn out on it's own. Note that resin DOES get warm as you mix it, this is normal. Make a small batch of resin so that you can feel what it's supposed to do with normal mixing before you mix up a big batch. Big batches are harder to mix evenly and will cool off much more slowly than a small batch, so have a greater risk of exotherm. Due to the threat of exotherm, I strongly recommend mixing the resin outside. Or at least in a garage, close to a door where you can throw it out of the house if the bucket starts smoking. If you have a friend that is an auto-body type (or a modeler that has done this before), ask him for help for your first time working with resin.
@Section9 Thanks alot #9 for all this info. I'll remember to put it to good use. How old are we talking about? A week, a month, a few days?
Well, for airplanes, if it's past best-by date you throw it away (expensive, but cheaper than lives!). If it's Bondo (fiberglass epoxy for auto body work), well, as long as it actually does cure you're OK. Probably half the time Bondo flakes off the body panel it was old when mixed. But if you can avoid it, don't buy anything past it's sell-by date. Good resin will have a use-by date, I've seen larger bottles with use-by dates printed or stamped on them. *rummage* Huh, that's funny, there isn't a date on the bottles of Alumilite casting resin I have, and several of them are... elderly... But they are only ~4oz, so no huge loss if they've gone bad. Getting fresh RTV is more important than fresh casing resin, anyway. if a casting pour doesn't set, it's no great loss, just throw the whole mess away. But if the RTV doesn't set, you may have to get creative to salvage the master model inside it!
@Section9 Thanks again. First things first I need to pick a good resin kit to get the hang of the process before buying the stuff in larger sizes.
After @Section9 gave this incredibly informative primer on resin, i have to include the alternative with the thermoplastics: If all you want is an extra gun, sword or something like that, and don't mind a slight loss of detail, thermoplastics are by far the simplest way. Here's a video: One thing not mentioned yet is silicone molds, these are in my opinion the best middle ground, full detail without the issues of making resin ones. Here's a quick and dirty primer: None of the solutions is perfect, but who needs perfect anyway?
I recommend getting few syringes as well (no needles though). That way you can easily get the right amount of resin to be mixed. So basically you use one dedicated syringe for resin and another for a hardener liquid. Try not to mix them ;) If you are casting small parts like heads, you might want to use another syringe to inject mixed resin into the moulds. Just remember to expel leftovers out of the tubes at the end (all synergies). That way you can use them many times for casing. Also, you might try a thin piece of wire or a toothpick. Once you pour/inject resin you can use those to gently reach recesses areas of the mould to remove little air bubbles. Good luck ;)
I've used the syringe method myself - but I use them for air extraction from the extremities (my moulds DO have vents in them, but sometimes they just need a little more encouragment to bleed the air out and pull the resin through) of my small pieces.
Apparently there's some acrylic resin that is way easier to use and is a good before investing in ''classic' resin.
Polyurethane as classic, then polyester as ancient? IIRC the acrylic is a French thing, not very spread, the one I know is called Acrystal, maybe similar products avaliable outside Europe. Never tried, so no idea if it will flow and solidify good enough for so tiny things as Infinity miniatures.
Honestly I've just found it today on Green Stuff World by browsing their catalog (I was looking for masking putty). Maybe a French thing, but it's sold on a Spanish site ;) So far I only use milliput and oyomaru. I had to duplicate a missing head once and the result was pretty nice.
Oh GSW one... different thing, I saw it time ago, but didn't remember, probably because it got under "special plaster" in brain (thick blocks like bases and barrels). You add water to that, the other is liquid plus dust. OTOH, maybe the "plaster" is two things A+B, and the other is water+A as liquid and B as dust. Well, no info about how flexible it is, and for small things you want something slightly so, not brittle and cracking to the smallest hit. Not expensive test, but maybe not what he needs.
My supplier doesn't carry the polyester resins in their store anymore (they still have them in the warehouse, but they stink up the store, so they don't put them in the store. They tend to use an MEK catalyst, and it reeks). In comparison to the variety of RTV and other silicones and the variey of polyurethan resins (foaming, flexible, clears and so on) which don't smell at all (it's all relative).
Toxic, carcinogenic, teratogenic, explosive ... it's why it's oft referred to as "Methyl Ethyl Death".
Evaporates from body temp in seconds, skin absorbed so fast that puddle on your palm you just watched evaporate is now detectable in the air you're breathing out, and will happily take the round right off a bowling ball! Yeah, don't mess with MEK if you can avoid it.
