Clear FLGPLC02 Brittleness

I manufacture lots of tiny parts for scale model trains. I find that the clear resin is terribly brittle. Is there anything that I could use to treat the final build to strengthen it. i.e. some chemical that would act as mild plasticizer perhaps. The alternative is for you to advise me as to what resin I should be using. like I said, my parts are tiny and fairly rigid so the material should have very much the same properties as is used to injection mold model aircraft kits.

For tiny parts I use black resin. It’s touch enough and can be used without varnishing. For bigger parts, black is unusable because of heavy warping. Grey warpes less, but visible.
The model trains in the picture are scale 1:87. Left: model made of injection molding (industrial model), the added coupler is black resin; right: model case grey resin (varnished), coupler black resin, wind screen clear resin (polished and coated with a decal)

In future, I will use clear resin for cases and chassises because clear resin warpes barely.


Please contact me on We can share so much information on manufacturing HO & N scale models. I manufacture a huge number of South African models ( Look for Scalecraft on Facebook ) I laser cut, cnc, brass etch and resin cast my parts. I am slowly moving over to 3D printing parts but they break so easily. I printed air horns and vacuum pipes but they are not really usable. I was contemplating making RTV molds and casting them in white metal.

BTW: Your work is absolutely beautiful!

The clear resin breaks too easily. I printed N scale bogies but they shatter if they are dropped,

All of the regular resins are pretty brittle, if you drop them they will probably break.

FL has “Tough” but I’ve found it is too flexible. Thin walls and beams are easily deformed. Even post cure the consistency is more like semi-melted plastic. It takes a huge amount of distortion without failing, but I’ve found it to be hard to get the parts dimensionally stable enough to use them.

But there are 3rd party resins. I’ve been pretty happy with MadeSolid Vorex resin. The parts are very stiff like the generic FL resins, but significantly stronger under stress.

This part completely recovers after being deformed, springs back quickly. You can get an idea of how hard I’m pressing by looking at the blood (lack thereof) in my thumb.

Hi Randy,

Do you always use the Orange? I’ve used the black, and was not all that happy with it. The surface got chalky, and it never really felt ‘done’. I’ve mixed Vorex Black with clear and tough with some success, but I’m not sure what value the Vorex really added other than the darker color…

Guessing, that orange looks as hard as clear but springy. Does it finally cleave like clear at failure? Does it ‘creep’ over time under stress? Would you recommend it for parts that snap fit?


what settings do you use in your Formlabs printer when printing the Vorex?
Looks awesome.

I followed JohnK42’s suggestion and switched to the black resin. Wow, that solved the problem perfectly.

Here are a couple of pics of the model

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Very nice

BTW: I created the platform and each “support strut” as separate watertight objects. I simply intersect them as required and then export the entire lot from Rhino. I think that the engine within PreForm does a repair job and merges the objects together. This works like an absolute charm and saves me from having to carve my model up by having to union the support structure into the model. My working model is separate an correctly aligned to the CPlane. Once I am happy with the model I create a copy and then flip it over on its back and tilt it in the various planes so as to ensure that the build process does not have any undercuts. Then it is simply a matter of aligning my model above my platform and extending the support struts until they interest the model nicely. The great thing is that once you have this lot set up it is merely a matter of using the support structure and slapping your new model on top of it.

This is what the CAD layup looks like:

It will still exhibit a “glass like” fracture when yield is exceeded. But it takes a lot more effort to get there than with the standard FL resins. The material doesn’t appear as yet to exhibit any creep. I haven’t evaluated it for how properties change with heat. I used Vorex White and found it to be a little more brittle than Orange. I have some Black Vorex but have only printed a few small parts with it, that I haven’t really done much with.

Whatever Vorex said to use, I think FL “Grey 01”.

Can you just use the MadeSolid Vorex resins in the FL2 or is it necessary to run with adjustments made to the printer?
Running in open mode?..
Also, the orange material you show in your photo, is it somewhat transparent / clear? I’m having trouble finding it on their website, can you post what it’s called?

Thanks very much for the help.