Molding technique for newbie to make a poseable part

Regular model paints won't work on a flexible surface like a urethane or especially a silicone rubber. You need specialized paints (or pigments). Regular hobby paints would crack and chip/peal off after being flexed and posed. They won't even stick to a silicone rubber. There are specialized silicone paints you use to paint and detail silicone as there is for urethane casting rubber used in stop motion puppet construction.

Yes, but that's not what the original author is wanting to do. In order for him to accomplish what he wants to do, the entire lower limbs of this kit would need to be re-cast in urethane rubber w/aluminum armature wire inside. The kind used for castings in stop motion (or silicone). Both need to be degassed for casting or else the amount of surface bubbles on the re-cast parts will be a daunting task to fill in and you can't use a hard filler on a flexible part. I.M.O you might as well start over if the surface bubbles are really bad. Even if hard fillers  "stick" on the rubber urethane parts, it will crack if not fall out and guaranteed it wouldn't work on a  silicone cast piece. 

missileman2000

 

 

jpolacchi

You can't use, "putty" to fill in on urethane or silicone rubber. Its best to degas the rubberin a pressure chamber for a job like this. 

But urethane resin used for molding is not a rubber.  I use fillers frequently and they stick very well.  If urethane resin is properly cast it has a very hard surface.

... and many of the flexible makeup casting products (noted above) are paintable

jpolacchi

You can't use, "putty" to fill in on urethane or silicone rubber. Its best to degas the rubberin a pressure chamber for a job like this.

 

You can't use, "putty" to fill in on urethane or silicone rubber. Its best to degas the rubber in a pressure chamber for a job like this.

I was going to suggest that to him, but...that's a whole different kind of casting and I have seen the kit parts (I had to look up pictures), aside from the larger ones that come from the kit that start at the base of the body, the rest of the legs are too skinny  for joints where putting armature wire inside is the only way it would work. Those long, skinny limbs would need to be re-cast out of a flexible urethane rubber(and then painted). Its possible the base color may be able to get mixed into the rubber when casting(maybe?), but it would still be getting painted/weathered and detailed.If you want to make it look right, its not just casting the legs. You need a degassing chamber to remove all the air after mixing because it would be a real P.I.T.A to fill in all the voids left behind after casting. It woud be worse than filling in on a regular resin cast. Plus you need, "special paints" to paint urethane rubber (or silicone). I'm not saying it can't be done, but this would be an expensive project if someone wanted, "to do it right" and you need to know what you are doing.

JimC2020

I bought the Pegasus Hobbies 1/144 War of The Worlds Alien Tripod and what I was hoping to do is to make a cast of the legs and put some sort of bendable wire in the newly cast part so I can pose it a bit. From what I can tell making a mold from the plastic should be pretty easy since the part is super complicated. But what kid of material would I use for the part? Silicone? It seems like silicone would be nice but appears that you can't paint with acrylics? Is there anything bendy like silicon that's easier to work with for something like this, and can be painted?

 

Go to Smooth-on https://www.smooth-on.com/   They are a producer of many resin & RTV materials for hobby & industry.   Check their FAQ sections, and particularly their cosplay and theatrical makeup sections for flexible resins which you could imbed a wire armature.
Check too their distributor list for an outlet near you.   There is one nearby to me and the counter staff is helpful and able to answer specific application questions.   They also have occasional hands-on classes.   Get on their mailing list

Hi:

        Rather than do that, how big in diameter are the legs? You could drill holes in the sections and put bendable wire in the holes(c/a glued in place) and then adjust accordingly. This is what I do, even on 1/35 scale figures so I can reset their positions later! I was going to do what you asked about and another modeler (Who'd been doing it longer) suggested the K.I.S.S. method I described.  It's never failed me yet even in 1/72.

       I failed to mention here that the kits I have done this on are Styrene only!

I find the silicone mold material and urethane casting materials easy to work with.  They have become the go-to materials around here.  There are many refereences available. Mold design is important for reducing air bubbles, but even if you get them they are easily filled with putty.

It’s a little hard to know what you are talking about if you don’t have any pictures? I sort of understand what you are wanting to do, sort of turn your static model into a very basic stop-motion puppet. Its easier said than done. How complicated are the kit parts? I wouldn’t know unless I saw them? You might be able to get away with some basic surgery on the kit parts themselves if the legs can be separated without destroying or completely runining the integrity or detail of the legs. It really depends how articulated you want to make the legs?

If you do a web seach, you can also find some basic stop motion joints online. There are a couple web sites I can think of who make them. I think they make ball&socket joints and some might make hindge joints too but I am not 100% sure about that? If you can modify the kit parts legs, you can attach the stop motion joints inside the legs, and if you still wanted to go with the aluminum armature wire idea, you can certainly do that as well, but they will not last as long if you want to repose your figure. The aluminum aramature wire will eventually breaks.

I don’t think you want to monkey around with casting silicone or urethane rubber legs and using silicone or urethane paints. They are expensive and if you haven’t used them before, you may have a hard time. Plus casting and recasting silicone pieces, theire a bit to do that to do it correctly. If you have photos post them and get close ups of where the joints are so I(or others) can see. I did find a pictre(but a bit too small), but i thin you can do it making the legs partially articulated(very limited movement), but from what I saw, you could do it. If you really wanted to make the legs fully articulated, you can to decide how much scratch building you wnat to do or casting rubber parts as leg replacements.