8 replies to this topic

[Mike Patterson]

While looking online at some 1/18 scale models, I noticed some of them were "resin cast" instead of the more familiar "die cast". Does anyone here know the difference?

 

BTW, this is the model that got me wondering:

 

I've always liked the 2K, and I might have to spring for one of these. IF it goes into production. They are available for pre-order, but I'm kinda leery of that after my experience with Exoto.

[MattD]

Die cast is metal and resin is plastic, chemically cured.

[Dave Crevie]

Large scale resin models have a problem of warping over time if the right resin is not used. I have been casting resin

models for about 40 years, first in model railroading, and then about ten years ago I got involved in casting slot car

bodies. Around 1980 I found a commercial supply company that sold an extremely high quality resin, that had good

detail reproduction as well as being very strong. They also sold a flex agent for this product that made it highly impact

resistant, great for slot car bodies. Sadly, three years ago the supplier went under due to the loss of manufacturing

in this country, and the fact that they had never bothered to get ISO registered. So they could not get any overseas

sales. I would have to hold one of these models, as shown in the OP, in my hand to make any real comment. Certainly

weight is a consideration, because the heavier the model is, the more likely it is to sag out in the middle. 

[MattD]

A lot of the resin I still have that I  did back in the 90's is still in excellent shape.     I think it is more important that it is a quality plastic and that it is mixed properly.

 

Improper mix will tend to not retain it's shape over time.   

 

There is a lot about this I don't know and I admit it!

[Mike Patterson]

Thanks for the answers, gentlemen. No way am I paying $249 for a large chunk of plastic. I guess I can cross the 2K off my wish list.

[munter]

Certainly weight is a consideration, because the heavier the model is, the more likely it is to sag out in the middle. 

 

In my experience thicker resin tends to be more rigid. There are many types of resin with different pot life and hardness(shore) ratings.

 

Some of the older resins are like working with concrete.

 

I work in 1/32 scale and have only experienced warping, twisting or sagging when the model is stored incorrectly such as on an uneven surface in a warm place.

You can correct it with repeat applications of hot water and opposite twisting, then some rapid cooling. Three hands can help in this process.

 

I would think these high end resin models would choose their materials carefully.

[Dave Crevie]

Generally models 1/24th and smaller will not cold-flow with time, partly because there isn't much weight there. And the

thickness of the uncured resin really doesn't have anything to do with how strong it is. Strength is a factor of what is 

added to the resin to give it more strength. Most resins use talc to increase body, but that does not add appreciable

strength. Tensile and impact strength is increased by adding polyester beads or ground fiberglass. There are other

materials that can be added to modify the physical principals of the cured product.

 

Large models have more weight, and quite often there is a long span between supporting elements. And since two-part

catalized resins don't cure 100%, some cold-flow will always happen. It may take many years for it to be evident, but it

will happen. 

[Mike Patterson]

The thing I like about die-casts is the heft. They have weight. They feel substantial. Most plastic models seem too light to me. I've even added lead to some of my builds to make them "feel" right.

[Dave Crevie]

If it is a static model, weight should not be an issue. If it is too heavy, and never moves, the tires could be flat-spotted.