Results on Test Prints with Formlabs and Vorex resins

Continuing the discussion from How to make and maintain less brittle prints:

I’ve been really busy since my last post, but I figured you guys took the time to reply to me, so I should share the results of my test prints.

Formlabs resins - The clear is definitely the strongest of the formlabs resins, but even this will go extremely brittle if untreated and left in direct sunlight.
Vorex resins - I got a litre of their black stuff - the flexibility on this is incredible - really strong, and I could bend a glasses leg over double - it took about 4 or 5 goes doing this to break it. However, because the surface is really ‘rubbery’ sanding off the build lines and getting a nice finish is really difficult.

For finishing, I tried a number of approaches.

XTC 3D (with and without acetone)
XTC 3D with embossing powder
XTC 3D plus Krylon
Envirotek Lite
Polyurethane finish

Bit of a mixed bag of results. The Polyurethane gives a slight yellow tinge, so no good for clear prints. The PlatiKote is worse than useless, don’t waste your money. XTC 3D is a funny one - it made the Formlabs prints a lot more flexible (and you can add metal powders, glitter, paint, etc. to the finish, which is cool). In fact, it became almost as flexible as the Vorex prints, but still needs a UV protector. On the other hand, the Vorex print became more brittle when coated in XTC 3D - to the point they snapped in my hand. Krylon on its own gives a nice finish, and keeps your print protected, but doesn’t do anything for its strength.

The real star of the show was Envirotek lite. When coated on either print, it made them more flexible, and gave a nice even finish. Coupled with a Krylon finish it gave me this on a little dragon keyring model I printed off (still drying in this pic):

I’ve been speaking with the guys at MadeSolid, and they will be releasing a clear Vorex in the near future, which is quite cool. I’ve also invested in an air eraser (still to be delivered) which I hope will clean the build lines off the Vorex prints without leaving scratches on the base print (which is what happens, the stuff is like cream cheese when you attempt to sand it down).

For the sake of completeness, here’s a shot of some of my test prints (sorry about the dodgy focus) - from left to right, Formlabs clear with XTC 3D with sparkle embossing powder, Formlabs black with XTC 3D with sparkle embossing powder, Formlabs clear with Envirotek Lite and Krylon, and finally Vorex black with Envirotek Lite and Krylon:

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After a few days do the models retain the above added stregnths you noted above with the coatings?
So if your looking for the strongest possible model would you recommend the Vorex with the Envirotek or the clear form labs with the XTC 3d.

Depends what you mean by strongest. Vorex is strong and flexible, Formlabs clear is strong, but with a hard finish (easier to polish up, but more brittle, especially for thinner parts). If you want kind of strong and cosmetically nice, Formlabs, if it has to be strong and flexible, Vorex.

I would only use XTC 3D for cosmetic purposes i.e. if you want a metallic or glitter finish on a print. Envirotek is optional on the Vorex, but, I think, necessary for durability on the clear (The dragon keyring is being used by my son, has taken a battering, and still looks like glass). I would recommend Krylon for both resins, especially if they’re going to be in direct sunlight.

Thanks, I was referring to brittleness and flexibility.

Do you find that any of the coatings you applied allow for the very clear look that you see when the part is fresh out of the printer.

If you look at the pics above, you’ll see that the dragon keyring and the third test print on the 2nd pic are pretty clear. In my limited experience, I’ve found that a wet sand, followed by a sanding with a smaller grain paper, leaves your print like sandblasted glass. Applying a thin coating of either XTC 3D or Envirotek brings it right up to a glass finish (If you have a look about this forum, you’ll see some people have gotten amazing results with just elbow grease, but I’m not that patient). Besides the pros and cons I’ve listed above, XTC 3D is more expensive, but has a 4 hour cure time. Envirotek is closer to 48 hours.

For clear parts, Krylon, or some other UV protection, is a necessity, otherwise natural UV exposure will turn your print yellow over time.