Smooth-On XTC-3D™ 20 Mold Making & Special Effects Silicone Rubber, 3D Print Coating - 6.4 oz

XTC-3D is hands-down a must have for anyone with a 3d printer. I usually print in ABS and follow the old "tried and true" method of sanding followed by vapor smoothing followed by final sanding before painting. XTC-3D eliminates the need for all that extra effort. To ensure a problem-free flawless finish: - Make sure that your part is clean. Use isopropyl alcohol, acetone, or whatever appropriate cleaner for your material to wipe your print clean - Mix the resin with the hardener in the exact ratio specified. Adding more hardener than necessary will only increase difficulty in applying it. Make sure that you mix it THOROUGHLY! I cannot stress this enough; You must mix it and continue mixing it until it becomes crystal clear. The longer you mix it, the better your finish will be, but the shorter your working time will be. I recommend mixing small batches at a time - you can always mix more if you run out. - Make sure that the ambient temperature is within the recommended range. Trying to coat your print when the temperature is below 70F will obviously increase the time it takes to fully cure. The mixing cup that is included is flimsy and not very strong. I made the mistake of mixing a batch and leaving it in the cup while applying it and the heat nearly turned the mixing cup into jellly and rendered it worthless. After mixing, pour it into another container, onto some aluminum foil, etc then wipe the mixing cup out with a shop towel, paper towel, etc. The foam brush is not worth the hassle - this holds true for ANY foam brush. I recommend you get a decent paintbrush instead. The foam brush soaks up too much and deteriorates too quickly, but a paint brush can be cleaned out with acetone and reused several times. I was so impressed with this stuff that I ordered 24oz of it. Follow the directions, do the prep work and you will end up with repeatable flawless results.

I'm a big fan of Smooth-on products. Their OOMOO is great and I've dropped serious dough on their products over the years. Surprised with this, however. More than anything I'm not really sure why it's said to be specifically for 3D prints. It's basically the same as any other epoxy I've used just in a 2:1 mix ratio instead of a 1:1. My guess is that it allows you to mix smaller amounts with better accuracy but I could be wrong. Super high gloss. Easy to tint with acrylic paint or food coloring. Too thick to self-level but not thick enough to not run on vertical pieces. I don't hate it but I don't think I'll be buying another kit once this one is used up. Pretty stinky too, which makes sense for what it is, but if you mix more than a small amount make sure you've got ventilation. Pro tip: let it cure under your stove's (turned-on) exhaust vent (if you have one).

It says "3D print coating" but it's really a brush-on, thin epoxy filler. I recommend you use a thinner mixture than what the instructions state to make. Doing so makes it a tad easier to work with this product. That's a good thing if you have an especially large printed object. Wet sanding is also recommended using progressively finer sandpaper. Overall, it's a good product, but not really needed with the newer generation 3D printers that actually print significantly smooth objects.

Great stuff if you’re doing 3-D prints

I had imagined such a product since I began printing in 3D with an FDM machine and I'm glad I discovered XTC-3D High Performance 3D Print Coating. One drawback to FDM printing is that prints are not fluid tight. While I won't say this coating will make prints completely water tight under pressure, It goes a ling way to eliminating the small pores left in the print by the FDM process. Now my prints for fountain heads and water features, if coated inside and out, work very well without any pinhole leaks. The trick is making the inside large enough so the applicator will fit. The kit comes with only one mixing cup and one sponge applicator so plan on a trip to the craft store for more, because there is enough of the part A and B material for many applications. The result is a hard clear surface that you can sand or paint if you so desire.