What is resin?

[allegheny]

Sorry for such a dumb question, but I'm only familiar with "plastic' model kits. What exactly is resin, and what are the basic differences between resin and plastic? Thanks!

[Mike Kucaba]

Basically, all plastic is resin and all resin is plastic... The difference is how they are used. Plastic,usually is used as a super heated liquid 400 degrees or higher,which is pushed into a mold at forces at or above 500 tons. The resin we talk about here is two chemicals mixed together and thru an exothermic reaction solidify in a (usually) silicone rubber mold and become a resin body ,hood or whatever the mold represents.

[Harry P.]

There are two basic differences between an injection-molded kit (what we all call a "plastic" kit) and a resin kit.

First, the plastic material used in almost all "plastic" kits is polystyrene, and is different from the material used in resin kits.

But the main difference between a "plastic" kit and a "resin" kit is how they are manufactured.

An injection-molded plastic kit (the typical "model kit" we all know) is manufactured by injecting liquid (melted) polystyrene plastic under pressure into steel molds. The liquid plastic fills the voids in the mold, and when it's cooled and solidified, the plastic is removed from the mold. The parts are typically molded in groups, attached by thin connections to a framework that holds the parts (called the parts "tree").

A resin kit (or resin parts) uses a completely different manufacturing process. The resin in a liquid state is poured into a mold and allowed to harden, then is removed from the mold. The difference from an injection-molded plastic kit is that the resin is liquid at room temperature, and is not injected under pressure into the mold cavity... it's simply poured in, and gravity causes it to flow and fill the mold.

The injection-molding process employs very elaborate (and expensive) metal molds and injection-molding machinery, and lends itself to high volume production. The resin process is generally used by the aftermarket because the start up costs are much less than that required to do injection molding (no injection-molding machinery needed), the rubber molds are much easier and cheaper to produce than the steel molds needed for injection molding, and the resin casting process is much better suited to the small scale (even individual piece) production needs of the aftermarket.

As far as the actual differences between resin and traditional kit plastic when you're building, resin in general is more brittle than styrene plastic, and will snap and break much easier than plastic would. Also, the typical "model glue" used on a plastic kit will not work on resin; typically you would use either cyanoacrylate glue (Super glue) or epoxy with resin parts.

If you want to know more about the resin casting process you can google it and find a ton of information. Here's one place to start:

http://en.wikipedia.org/wiki/Resin_casting

[diymirage]

resin is as resin does

[Craig Irwin]

Basically how this relates to us is injection molding equipment used to make plastic models is very expensive and requires expensive molds be made by tool engravers. Resin can be cast in simple molds of rubber by modelers in there spare rooms or garage, The "tooling" is nothing more than a model itself, either an original part or something hand made.

[Boreham]

Hi Paul,

When referring to resin in model making (car's ,boats ,planes,etc ) it's a 2 part liquid that's mixed.

One part is the resin and the other is the hardener.The mixture will harden quickly depending on the ratio and the ambient tempreture at the time of mixing. it should pour with a nice consistancy (like partially whipped cream)

It's used for small batch work and or upgrade items for existing kits, usually fairly costly to purchase due to limited run the nature of the market it's aimed at.

There are a variety of differences between using/building with resin which more experenced modelLers here may Identify for you ,as I've not built much myself. Wear a mask when sanding this stuff during clean up and preperation for paint as it can be toxic .

The "Plastic" used in industrial manufacture of model kits bares no resemblence to resin and is normally in granular form prior to entering the Molding machine,which in itself is a topic of it's own.

[Romell R]

There are two basic differences between an injection-molded kit (what we all call a "plastic" kit) and a resin kit.

First, the plastic material used in almost all "plastic" kits is polystyrene, and is different from the material used in resin kits.

But the main difference between a "plastic" kit and a "resin" kit is how they are manufactured.

An injection-molded plastic kit (the typical "model kit" we all know) is manufactured by injecting liquid (melted) polystyrene plastic under pressure into steel molds. The liquid plastic fills the voids in the mold, and when it's cooled and solidified, the plastic is removed from the mold. The parts are typically molded in groups, attached by thin connections to a framework that holds the parts (called the parts "tree").

A resin kit (or resin parts) uses a completely different manufacturing process. The resin in a liquid state is poured into a mold and allowed to harden, then is removed from the mold. The difference from an injection-molded plastic kit is that the resin is liquid at room temperature, and is not injected under pressure into the mold cavity... it's simply poured in, and gravity causes it to flow and fill the mold.

The injection-molding process employs very elaborate (and expensive) metal molds and injection-molding machinery, and lends itself to high volume production. The resin process is generally used by the aftermarket because the start up costs are much less than that required to do injection molding (no injection-molding machinery needed), the rubber molds are much easier and cheaper to produce than the steel molds needed for injection molding, and the resin casting process is much better suited to the small scale (even individual piece) production needs of the aftermarket.

As far as the actual differences between resin and traditional kit plastic when you're building, resin in general is more brittle than styrene plastic, and will snap and break much easier than plastic would. Also, the typical "model glue" used on a plastic kit will not work on resin; typically you would use either cyanoacrylate glue (Super glue) or epoxy with resin parts.

If you want to know more about the resin casting process you can google it and find a ton of information. Here's one place to start:

http://en.wikipedia....i/Resin_casting

This is on the money!!!

[allegheny]

Thanks for all the great responses! Now, I know alot more.