For those of you who had worked with resin parts, are they hard or soft? Are they brittle if the parts get too thin? Do you ever break a part accidentally? Are they flexible? How do they differ from plastic parts? Why is it that everybody perfer resin parts over plastic? Please describe what resin parts are like to me. I want to start working with them and maybe get an idea of what they are.
Well, I hope I’m not going to write all of this and then find out that somebody beat me to it while I was typing, so, just for the record, I was first… [:D]
First, Resin parts are very hard, in fact, resin is a hard liquid. (weird, huh?) Resin is cast in flexible RTV (Room Temperature Vulcanizing) rubber, and plastic in kits are made with huge metal dies (non flexible) that are injected with melted styrene. Resin can break easily if you exert too much force on small pieces, but it really depends on the type of resin. Tank Workshops’ resin is actually pretty soft, and can easily be carved with a #11 blade, while other manufacturers like Verlinden use a more brittle resin. This resin requires a razor saw with about 18-24 Teeth per inch (TPI) to cut through it, sort of like a slow bandsaw.
RTV molds last about 100 - 150 casting before they are useless, but an injection molding die for plastic lasts forever.
I break a lot of resin parts, but most often it is the tubular/rod parts that are more lengthy than they are wide, I almost never break anything else. The only thing that was really “broken” for me was from FedEx, they damaged and chipped the edges of my afterburners (I put the chipped parts on the undersinde).
Almost nobody that I know prefers resin over plastic. Resin can warp badly, and has many other cons for large surface areas required for a model. I definately prefer them for detail, because resin is sometimes the only way to get the detail I’m looking for.
To get resin off of the pour blocks (large cubes attached to one side of a cast resin part, think of this as the sprue of a resin part), you must use a razor saw that I mentioned earlier. You can also use a mitre box to get a straight line, but I usually don’t. After you get a good deal of it removed, head back and sand it to the correct shape, leaving a resin piece that looks perfect.
During all sanding, it is a very good idea to wear a RESPIRATOR. Resin dust is harmful to the body, specifically the respiratory system.
Hope this helps
As MC already mentioned, usually the smaller parts can be more fragile, but that’s true with anything really, styrene or resin. Depending on the manufacturer, the “pour plugs” that the resin pieces are attached to can present some challenges. You can use a razor saw to separate them if they are large or very carefully use a pair of sprue cutters…just be very careful as resin will behave like glass when subjected to cutting stress…it can split/crack in really odd ways depending on the strength/density of the cast object and how uniform it is/isn’t.
Resin is preferable to styrene only when a) it provides more detail due to the casting process or b) presents parts/subject/conversion that aren’t available in any other form. Not all resin parts are the same, depends on the caster and what they used and how good/bad the quality is of the finished parts. I’ve seen some fabulously well done resin pieces and some equally bad resin pieces…sometimes even from the same manufacturer! [:)]
Resin is much heavier than plastic, requires the use of epoxy or CA type glue to attach, and has some health hazards (like anything in this hobby) with the dust.
Royal Model produce some beautiful and superfine resin accessories! I’ve jus’ had to clean out the handles on some jerrycans which had a film of resin closin’ 'em off. I did this with a scalpel and some small pieces of sandpaper. The handle rods are about 1mm thick, and yet they stood up to the treatment and didn’t crack or break! [:D]
Personally, I think it’s down to the manufacturer and their processes whether you have good experiences of the stuff, or not! Royal Model are top quality, though! [;)]