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Jun 2016

Hi, so I’m printing this vase for a girl I like. The thing is, you can clearly see the 3D print lines and the surface is kind of rough. What is the best way to get rid of this? I am printing in PLA btw.

  • created

    Jun '16
  • last reply

    Oct '17
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The best way is quite subjective. It depends on the person, the skillset, the budget etc. Xtc-3d by smooth on along with similar two part casting resins can coat a print and give it a clean smooth surface. Priming and painting. Glazing compound. Sanding and polishing with buffing wheel and compound. Rock tumbling with various media and polish. I’m sure wax dipping is a thing though it may warp the PLA…

I thought I had a youtube video for you but I don’t so I will try to explain in text.

You want to use sand paper as acetone doesn’t work on PLA. Depending on the thickness of the model walls depends on what grit sandpaper you use. If its a single layer wall its going to be hard. If the wall is 2 or 3 layers thick and is 300+ microns than start with 150 grit. If 250- microns start with 250 grit and work your way down. I print with 250 micron layers and 2-3 layer wall thickness and start sanding with 250 grit and work my way up to 2000 grit. I go 250,400, 800, 4000 grit. WHEN YOU SAND MAKER SURE YOU SAND IN A CIRCULAR MOTION as the purpose of sanding is to make smaller and smaller scratches until they are invisible to the eye.

Ah, I see. The first few models I tested on I sanded back and forth causing the scratches you speak of. I will try sanding in a circular motion.

I’d like to use Xtc-3D but its so expensive lol. I heard there is a alcohol solution you can soak prints in or is it the xtc?

Don’t push very hard you want the grit of the paper to do all the work. You can use the 4 grits I said or you can add an additional in between 450 and 800.

If you are using PLA, sanding or XTC-3D is definitely the way to go! As a side note, if this is for a girl you like, XTC-3D is definitely worth the expense. Regardless, I’d use an electric sander if you have one, just to make things easier. There is already some solid sanding advice in here already, so I’ll just tack onto it: Make sure you aren’t sanding too hard/fast. If you do, the plastic will heat up again and you start scraping off large flakes and bits rather than fine material, and you’ll have to sand THOSE blemishes off.

Let’s not forget safety and PPE! Wear a respirator and safety glasses, especially if you are using an electric sander. If you are using one of those, you may also want to wear earplugs.

I forgot that part, definitely wear a mask! And not it in a well ventilated area.

Hi there! You are very right that XTC-3D is expensive! XTC-3D, also know as Smooth-On, is really just an epoxy resin with a fancy name. That being the case, I’ve had great success by using other epoxy resins that are available at home improvement stores or Amazon. I’m really partial to this one https://www.amazon.com/Clear-Epoxy-Encapsulating-Casting-Gallon/dp/B00IT0APVM 656, and as a nice little bonus, the epoxy includes UV inhibitors so it won’t yellow that quickly and protects the PLA a bit.

For finishing PLA, I start with 80 grit sandpaper (60 is too abrasive for most part in my opinion, but I will use it if there are noticeable flaws) and work my way up to 400 grit (80, 120, 200, 400). From 400 grit to 1000 grit (400, 600, 800, 1000), I wet sand to prevent buildup of heat in the PLA . I just stick the part in an appropriately sized bowl/container and sand the part under the surface of distilled water, and change the water between grits or when it becomes dirty. After sanding, I clean the part with water and coat with the epoxy resin. If the color of the part got to distorted while sanding, I’ll very lightly apply heat with a heat gun until the color is restored.

Is this a lot of work? Yes, but it produces really nice results.

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May I ask your detailed procedure? How to heat resin? Use hot water or heat directly? Do you heat the resin before or after mixing the hardender? Thanks.