First Impressions from the Smooth-On XTC-3D 3D Printed Parts Coating

7 Jan


We finally got our hands on a XTC-3D 3D print coating from Smooth-On, though it was not very easy to find it as most companies selling 3D printers and accessories for them still do not offer that product – we had to find Smooth-On partner in Europe and order it from them. We got the larger 24 oz (644 grams) package as the smaller one turned out to be cheaper than what we’ve had to pay for the shipment costs, and anyway if we liked the result after testing the coating we would want to have some more to play with. Once you get the package it is very wise to read the manual very carefully and do try the use the XTC-3D coating a few times on test prints, before actually trying to apply it to 3D printed parts that are more important. Also you would probably want to get some small size paint brushes for applying the coating to smaller 3D printed objects with more details, as using a large size brush on small 3D models is not a wise idea if you want to get good quality. Interestingly enough the XTC-3D 3D print coating can be used in multiple ways – to coat models providing a glossy and smooth surface effect, to coat them, then sand them and paint, or to apply color to the coating and coat the model with color. It all depends on what is the end result that you want to achieve in the end, what you need to be well aware of however is that properly using the XTC-3D coating does take some getting used to in order to achieve best results and it also takes some time for the coating to cure and additional time if you want to further process the 3D printed part.


We have started our testing with a 3D printed Yoda bust using PLA filament with a 0.3mm layer resolution, so the resulting print was with very easily distinguishable layers and not very smooth. The initial coating of the 3Dpritned part with the XTC-3D did make the layers of the print less apparent and the Yoda bust having a more glossy finish than what the original print had. We needed a second layer of coating with XTC-3D however in order to make the surface of the Yoda bust seem really smooth to the touch, although if looking up close you could still distinguish the texture of the different layers. The reason that you might still get to see very faint lines from the different players with a lower printing quality is that the XTC-3D coating is transparent, so even if ti makes the surface really smooth and glossy you may still need to apply some paint for 3D printed parts that use lower quality for the printing. The end results with 2 layers of XTC-3D coating to our roughly printed Yoda bust was really nice, smooth and glossy surface, though a bit of sanding on the ears and applying green paint could produce even better results after that.


Next up was trying out the Smooth-On XTC-3D coating on a few more exotic filament types – Carbon PLA from Proto-pasta, Laywoo-D3 and LayBrick from Orbi-Tech. using a 0.2mm resolution for the test prints we have applied 1 layer of XTC-3D coating to each of the objects – on the left is the normal print and on the right you can see the same 3D model with 1 layer of coating applied. The result with just a single layer was not that good, the coated 3D models got slightly more smoother, but with the layers still easily distinguishable and more noticeable was the fact that they became glossies as the normal results when printing with the filaments produce more matte look. Adding a second layer may improve things, but the highly glossy end result might not be to your liking that much and sanding and painting on top of 3D printed parts when using materials that produce carbon, wood or stone look is not the best idea as it will ruing the realistic look that they do provide.


We have also tried applying XTC-3D coating on NinjaFlex 3D printed keychain with the Nvidia logo, even though that might not be a very wise idea as this is a flexible filament. When you apply XTC-3D coating it hardens a bit the 3D printed part and make it less flexible, so this makes it unsuitable for flexible filaments as it will reduce their flexibility. After applying a single layer of coating to the 3D printed part with NinjaFlex filament we have observed the expected slight improvement in the surface feel – smoother as well as the keychain becoming glossier. Although the surface felt smooth, the topmost layer having a large surface area did not not look much more smoother tan before coating it, so XTC-3D might not work that well on flexible filaments such as NinjaFlex. The more interesting thing that we have observed is that after applying the XTC-3D on the NinjaFlex 3D printed keychain it has remained quite flexible, but stiffer than it was before the coating. You should however avoid flexing too much NinjaFlex printed parts if you have coated them with XTC-3D and also that if you apply multiple layers of coating their flexibility will most likely be reduced significantly.

So what ware our first impressions from using the Smooth-On XTC-3D coating? We are pretty satisfied with the results we got, although our first tries were not perfect we quickly got the hand of using the coating and the results started improving. When you get used to take advantages that the XTC-3D coating provides and you properly use it on 3D printed parts you can achieve really nice results in terms of final quality of the things you 3D print. The coating however is not perfect and suitable in all cases and for all kinds of materials, so you should be careful how and when you use it. You should also be prepared to spend some time for the extra finishing if coating 3D prints with XTC-3D as it does take some time to do it and then a few hours for the coating to fully cure. If you then plan on sanding and painting the coated part it could easily take a whole day, but if properly done the end result might be something that you can hardly believe was something that was 3D printed. We are going to keep experimenting with the XTC-3D coating, so expect more of our feedback pretty soon – next up is to get more experience with sanding and painting some 3D prints after getting them coated with XTC 3D.

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2 Responses to First Impressions from the Smooth-On XTC-3D 3D Printed Parts Coating



January 12th, 2015 at 09:47

I’d like to see test results on highly transparent filaments. Makerbot Natural PLA, generic “Clear” T-PLA, Taulman T-Glase, etc. That’s where this coating holds the most promise, IMO. It would be interesting to also compare the results from a simple coating of “dries clear” white craft glue, or Varathane.



January 25th, 2016 at 02:27

I’m Interested in in the Ninjaflex and XTC coating test you did. You mentioned it reduced flexibility but does it crack when bent to extreme angles (>80deg) or cause the part to be more brittle? Lastly, about how much would you say percentage wise did it reduce the flexibility (1% being extremely elastic (original Ninjaflex properties to %100 being as hard as ABS?)

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