During the 3D Show Printer & Scanner fair in Warsaw we met Peter Fusa of Łódź’s evoxel company, who just started selling this material in Poland and provided us with one of the first packages for testing. A month has passed since then, and we have conducted a series of trials and tests with the material. What XTC-3D is, why it is so special, and whether it is worth the money – you will find out all this in the following review.
XTC-3D is a material used for smoothing and post-processing of the surfaces of printed models. It consists of two components: resin and hardener – which should be mixed together in the right proportions. It is applied with a brush and when it solidifies, it leaves the printout with a gloss characteristic of the ABS treated with acetone. Unlike acetone, it does not change the structure of the material (acetone causes the ABS shrinking), it only covers it with some coating which can be later easily sanded. It comes in several colors and can be additionally colorized with a dye. We used the standard – transparent version. The material is not cheap – costs PLN 129.15 per pack, but it is quite efficient. We have covered approximately 10 prints with it and exhausted less than half of the package.
1. Getting started
The XTC-3D package consists of two bottles with the material, a container, two sticks for mixing, a manual and the product cards (in English). The larger container – labeled with the letter A, contains the resin, and the smaller one – labeled with the letter B, contains the hardener. The materials are mixed in the ratio of 2:1 (2 units of resin – 1 hardener). The manual warns not to mix large amounts of materials at once, because during the bonding process a high temperature may be generated. We have not experienced this, because we have never exceeded the minimum values (more about why that is so – below…). Unfortunately the package does not include a brush – so you need to stock up in advance, and it is best to buy a few of them at once. If you do not have any solvents at hand, the brush will be disposable.
The resin is very thick, but pours out of the bottle easily. The hardener is in turn very liquid. As befits a resin, it has a very distinctive “chemical” smell. The work with the XTC-3D should be done in a properly ventilated room. If during the work the smell is in no way bothersome, then later, when it is drying, it is neither pleasant nor healthy. The XTC-3D is not your typical modeling material, which you could use anytime at home, at the desk standing next to the bed.
Before you start working with the material, you should be well prepared for the job. The XTC-3D has a very short curing time after mixing, and therefore after mixing the components it is best to begin coating the model with the resin immediately. You should also pay attention to such details as how you are going to hold the model, or what is it going to be attached to. The material takes at least two hours to dry, so holding it by an appendix which you have just covered with resin is out of the question. Although it may seem obvious, keep it in mind from the start – otherwise you will have to paint the model in parts (which is sometimes inevitable anyway).
You must also not forget about some work gloves and a disposable surface (a old newspaper or any paper will do). The resin is very sticky and if your hands get dirty (and they will get dirty for sure), it is difficult to clean it off afterwards. The resin is actually not harmful to the skin (at least not to mine), but the contact with such materials should be kept to a minimum. It is also practical to place the printout on some surface that can be moved to a different place for drying. As I mentioned, the smell of the resin becomes very intense as it solidifies, and I would not recommend any work next to a drying model for 2-3 hours.
When you are ready to work, pour the resin and hardener into the container in the correct proportions, and then stir it for 2-3 minutes with the stick. When the material takes on a uniform, whitish color you can start painting.
2. Working with XTC-3D
Covering the model with the XTC-3D must be fast and effective. The operating time is about 5-10 minutes, with the first value being real, whereas the other one merely printed on the information leaflet. The longest period I have achieved was about eight minutes – afterwards the material thickened so much that it could no longer be spread on the model. Therefore, using the minimum quantities (0.5 ml resin and 0.25 ml hardener) is most sensible, since this way you can just narrowly manage to apply all the resulting “dosage”. The above times refer to the material spread directly from the mixing container. The manufacturer claims that it can be extended by pouring the material into a flat receptacle, but to be honest we have not tested it.
The XTC-3D can be spread on the model with ease and the process resembles regular painting. It is diluted enough so that there is no problem with even applying it to the model, and it is dense enough that it does not drip of while painting (though in the course of drying it does a little – though only from the fragments which are at high angles towards the ground, about 75-90º).
After the job is done, leave the model to dry. It takes about 2-3 hours at room temperature, in the winter, in a garage, at a temperature of a few degrees above zero, the resin will take all day to dry up. As for the container, we leave it to dry as well. The dried resin comes easily away from the container walls when you bend them a little. There is a problem with the brush, though. You could toss it into the container with a solvent, but it is in fact only a half-measure, because the resin will never come away completely. If you leave the brush to dry, you may as well throw it away. It is therefore sensible to use rather cheap tools, because the lifetime of the brushes is very limited when working with the XTC-3D.
Immediately after drying the model is suitable for further processing. The XTC-3D is great to polish, and there are no problems with painting either. Sanding or painting is not necessary, of course. The model can be simply covered with the resin itself and we will have a then glazy, shiny surface.
3. The printouts quality after covering them with the XTC-3D
We tested the XTC-3D on prints made of the following materials: ABS, PLA, woodFill and the t-glase. The manufacturers ensure that the material will also work on prints made of resin, gypsum powder or sintered polymeric powder and… I see no reason not to believe them. The material seems to be able to cover virtually any surface.
Once it dries, the model has a glossy surface that looks like ABS after a dip in acetone vapors. The difference is that the model does not lose its physical properties (it does not shrink), however, it loses its precision (or its specificity). The resin fills all the model’s cavities or indentations and whether they would remain visible depends on the thickness of the layer you applied on the model. Generally, you can see everything just like it was before painting (the resin is transparent), but the model becomes visually more ovoid and smooth. It all depends on what model we cover – if it is very detailed, it will lose its sharpness, if it consists of large homogeneous surfaces, the end result will be fantastic. It works also better with darker models – covering the bright or light printouts does not produce such a good visual effects.
You may sand the model afterwards without any problems – the printout becomes perfectly smooth and it is very convenient to paint on.
The XTC-3D is a material for professionals or people who will know exactly what to use it for. It is a perfect choice if you need to smooth the surface and fill-in the cavities of the printouts. Although traditional putty is undoubtedly cheaper, the XTC-3D is much easier to use. You can also use it to refining your print – if you have an appropriate model, painting it with the resin can take] it to a whole new level. And last but not least – models painted with the XTC-3D are perfectly smooth. If you have clients who pay attention to such details – when you give them a model that was covered with this material, they will refuse anything without it.
The issue of its price shall remain open… Apart from the fact that we got the whole package for free, if I had to buy it now, I would definitely do it. On the other hand, many people consider the material to be only a rather expensive curiosity – not everyone needs to refine their prints this way. In my opinion, however, this is the little something that can “make a difference” in a 3D printing service.