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Need help with 3D printed scenery


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Assuming PLA plastic...

There's a resin by the name of Smooth-on XTC-3D that's supposed to cover those pasky lines pretty well. 

 

If it's ABS, you could potentially use acetone vapors... But that's insanely flammable, so do it well away from anything you'd prefer to keep such as houses, cars, pets, eyebrows...

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Essentially, no. Especially in PLA, that's been a mostly-unsolvable problem. You're basically stuck with hours of sanding to get pieces finished the way you want. That said, there are a few options which help. Offhand, I know of vapor-smoothing and coatings. Some people have had some success with annealing as well, but I haven't seen anyone with consistent results from that yet.

 

Vapor smoothing

Vapor smoothing is essentially just creating an atmosphere that will melt the print, then letting it soak in that atmosphere for a while. For ABS, it's pretty straightforward to just use acetone vapor (though you are applying heat to create a highly flammable vapor, so do it outside). Link.  For PLA, it's similarly straightforward, but the chemical is much nastier (Tetrahydrofuran). Link. I have not been willing to mess with that stuff, so I can't tell you how well it works. 

 

Note that these techniques assume you're using pure PLA or ABS. Many filament suppliers add other stuff to their filament. That can make it print better, but can also make the material interact oddly with solvents. For example, PLA isn't supposed to react to acetone. Hatchbox black PLA leaches some white substance and turns slightly rubbery. What's going on there? Who knows! But be sure to test interactions against the actual material you're using before you try smoothing.

 

I would also be very cautious of doing this to paint over. Whatever you use for smoothing will stick around in your print, and may have unpredictable effects on long-term paint quality (kind of like how bones don't react well to some spray primers). I don't have much experience either way there, but it might be worth finding a way to seal your print extra-well to avoid that. I can say that both testors's gunmetal spray and army painter's angel green do fine (so far) over ABS glue, which is ABS dissolved in acetone.

 

Sealant

I wish there were a good answer here, but there isn't. There are products out there which claim to smooth out print lines, and there are people out there who claim to have used those products successfully, but I've never seen a perfect result from just sealant (or gap-filler, or ABS slurry, or whatever). I have seen some beautiful results from adding filler and doing a crap-ton of sanding, but you can get the same results from just the sanding (and my experience with PLA is that filler can come up in little chunks, making the sanding harder). 

 

"Annealing"

Annealing as a metallurgic technique means taking a piece of metal and baking it for a while at a temperature below its melt point. This lets the grains align and adhere better, so the whole thing is stronger afterwards. That works for printed parts too. I haven't seen a broad consensus on the right technique yet, but there's plenty of advice out there, and there are filament makers who make filament specifically designed for annealing after, so it's well past the "Hey y'all, watch this!" stage.

 

Some people suggest that this smooths prints as well; I haven't seen any examples.

 

 

Textured Spray

 

A few weeks ago, Knarthex was talking about finishing a printed terrain piece with a rough, gritty spray coating. That sounded like a promising line to me. You won't get a smooth finish or fine details, but you might not need them either. I have no experience either way with this, but in some cases it might let you avoid the otherwise-inevitable...

 

 

Bottom Line

You're stuck sanding anything you want to actually look nice. Make your peace with that, and you'll be happier.

 

 

Edit: that's all assuming FDM printing. If you use different printing methods, you get a different set of problems with a different sett of solutions.

Edited by fectin
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Okay, I have actually used gesso as a sort of layer filler. Yes, it'll take a bit of sanding, but since it isn't really that hard, it didn't take a lot of time to get a smooth surface. (Link to WIP thread). The more difficult parts were the curves, and they didn't get really that smooth. But flat areas worked really well.

 

It's still got quite a bit of layering look to it, but I was getting pressed for time before ReaperCon. The benefit with gesso is that it doesn't really have any toxic fumes to worry about. So depending on what you're actually doing, it might be something to try. Especially if it is your own printer that things are coming out of, so if you don't like the results of one, you can just toss it.

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I print at .18mm thickness in pla and find the resulting texture is not generally a problem, i would just paint over it. Where smoothness is called for, i would try using vallejo plastic putty.

 

Or you might try a midthick coat of gloss varnish, it should do the trick. Just matte varnish /prime it after the gloss is dry to make it paintable.

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I don't know anything about 3D printing so don't know the specs or materials.  It's the Earth Brewery by Dicey miniatures.  I was thinking of picking up an primer for wood rather than miniatures so it would fill in small cracks then sanding it and priming it again with miniature primer.  I was worried all the vertical and horizontal lines catching light would ruin any illusion of texture and grain.

 

Also considering using hot glue to at more realistic texture but have never done it on something this large so am a little gun-shy.

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I find that in practice, you dont really notice the print lines when the terrain piece is painted and on the table. 

 

I have been printing some 28mm terrain and 15mm tanks (1/100 scale) and I find those are perfectly acceptable as printed. There are some lines here and there, nothing too obvious.

 

3dprint.jpg

the white terrain pieces are printed at .18mm, the gray ones at .1 mm on my cheap flashforge finder plug and play printer.

 

I would recommend you start by not doing anything apart from the normal preparation ( clear off any chaff or spiky bits that might be left) and just go with it. See what you think of the results before going to all the effort. The slightly smoother effect might simply not be worth the effort.

 

If you set the print to .1mm (or as thin as your printer will print) it takes longer to print the pieces but the pieces are quite a lot smoother.and any stepping is much less notable. 

 

And of you paint thickish coats, most of that dissappears as well.

 

 

credits: The white pieces are bits from "winterdale cemetary", "straight walls" and "wildwood gnarly trees" from the printable scenery KS,

the grey are bits from "1:100 tanks by m_:bergman" thingiverse free files.

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Has anyone considered using Milliput as a filler?  It thins with water and you can get a very smooth finish, especially with some sanding.  Been a while since I used some so don't know how well price would scale with size of project.

 

I did use Milliput to smooth lines of quite a large print (wedding cake toppers for my sister). It works, but the thinning is tricky (it got too watery and without any real body). I ended up applying a very very thin layer of it to the most troublesome parts and then just sanding when dry, and basically sanding any lines that were small anyway. It was not going to get better with a bit of watery milliput on it, and I would have to do a lot of sanding in any case, so...

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So some folks use gloss sealer to cover small defects and mould lines while painting. Would something like gloss sealer work to smooth these things out?

 

This is pure speculation, I don't have a 3d printer yet. (Pirate 3D went belly up on their kickstarter, I'm out $400 until they get their act together)

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So some folks use gloss sealer to cover small defects and mould lines while painting. Would something like gloss sealer work to smooth these things out?

 

This is pure speculation, I don't have a 3d printer yet. (Pirate 3D went belly up on their kickstarter, I'm out $400 until they get their act together)

 

Yes, but not enough to avoid sanding, nor even enough to significant;y reduce it. And if you're committing to sanding anyway, sealer doesn't save you a lot of time.

Though, that does depend strongly on your layer height. With thin enough layers, raw + sealer might be fine. I haven't seen it work out that way yet though.

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