I have printed a lot of things but never finished anything. So in regards to PLA only for this thread, and besides using sandpaper, what are some common and best finishing procedures? I found that Ethyl Acetate is good to use but is it the best choice to smooth PLA surfaces? Or is spray clear gloss finish in a rattle can a good choice? Or epoxy? What is the least expensive, easiest, and practical way to finish 3D prints that have rough top surfaces?
Thanks
The tried and true method is a mixture of sanding, automotive bondo (or some other kind of filler), and filler primer. Once smooth you can paint however you need. Most of the time I can get good results with just sanding and filler primer if you are printing with small layer heights.
I tried out ethyl acetate for bonding Bambu’s nice Marble PLA. Didn’t do a thing.
So keep in mind that all filaments are blends that may have completely different chemical behaviour than expected.
Apart from that, using adaptive layer heights, I usually try avoid the need for post-processing. On the things that need painting, a fine layer height is usually enough even on low angles.
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How about heat with a hot air gun or a small butane torch? Just curious.
I think I will try the adaptive layer heights. Can I just put them anywhere if the layer that is rough is below that actual height of the finished print? And thanks for the info on the ethyl acetate so I don’t waste my money on it.
I have bondo. 
But, I wasn’t planning on doing any painting. But it’s still good info.
Thanks
Adaptive Layer height works globally on the part:
You can set more for speed or more for detail and just hit adaptive to compute a first suggestion. The bar on the right indicates at which height layer height is increased (red) or decreased (green) from your selected default. You can then just left- or right-click in the bar at a particular layer height to de- or increase the local layer height.
Don’t discard the Ethyl Acetate fully just yet. All filaments are blends and the marble is a peculiar mix. It may work on different filaments. The trouble is that we do not know what it actually is that we are using…
I have only used a torch for de-stringing. I do not trust my ability to control one enough to only smooth the edges.
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Thanks for the explanation. I have not yet used that setting ever but I have only had my printers a few weeks at most. I will keep the ethyl acetate on the back burner and may buy some soon just in case.
Adaptive layers were a real game changer for me. Also for things like PETG warping/curling control. Just keep in mind that you loose them when splitting a model they are applied on. They can be reapplied easily, but it is easy to forget… and two days later out pops a part with ugly 0.2 steps on a shallow angle…
Can’t you just save it as a custom profile? I see you have a X1C or at least the pic shows that you might. How do you like it? I was thinking about buying one but I was going to wait until the new printer they have talked about will be released in Q1 of 2025. I don’t want to regret waiting but there is absolutely no leaked details on features or more important price.
Adaptive layers are generated according to the geometry. So while it would be nice to always have them applied to a pre-defined speed vs detail setting, it is usefull to always think about that particular compromise.
The X1C is an amazing piece of work. I particularly like the auto flow calibration which really makes a difference for me. Manually calibrating a single filament is certainly possible. But when looking at multi-material printing with 5-8 filaments needing calibration… I just do not have that kind of time to prepare for what is my hobby.
That said, my first X1’s Lidar failed. Fortunately that was just before a legally important time-since-purchase had elapsed. It still took 5 months to get a replacement. Going cold turkey on FDM for that time was … tough.
Since development is going rapidly, the next generation is of course now coming to the market. With the next Bambu being highlighted as a prosumer printer, I expect it to essentially surpass or at least replace the X1E. And to be priced accordingly. Certainly above the X1C unless it will replace that as well.
I see Bambu in a bit of a conundrum though.
With the Qidi Plus4 offering a well thought out heated chamber and, by the reviews I have seen, performing at least on a par with the X1 but at the price of a P1S and with a whopping 370°C nozzle temp and larger build volume…
I would personally be very interested in high quality PPS parts as I’d have a number of use cases at work. And there’s another ultra-high performance filament I could get access to in small quantities that I’d be burning to try. Even the Quidi’s heated chamber is probably not enough, but, only doing leads to knowing. And with an AMS equivalent expected in 2025… Just not sure about the lack of auto filament calibration (which I would hate to do without), the place to put it, uncertainty on the Quidi-AMS (Anker failed with that last year for their M5) and of course wondering if the next Bambu can do 65+°C chamber temp and 370°C nozzle temp at a price suitable for a hobby (including the “backwards compatibility” question on the AMS & Hub (got 2 AMS, 1 Hub)…
Just like you, I am also torn in that regard, albeit between an additional printer in the form of a Quidi Plus4 now, or whatever Bambu will surprise us with next. If Bambu has been something in the past it was always and certainly surprising! But Quidi looks to be on a good track as well…
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Thanks for the thorough and detailed reply. I will have to play around with the adaptive first on a few smaller prints to get an idea of what to expect. I may only need to use it in certain scenarios and not all the time.
Interesting reply on the X1C and the new printer not yet out. Also the Qidi Plus4 option. I didn’t look at any other brands and I already have a Prusa MK4 but am not entirely impressed with cost vs everything else including spare/replacement part prices/availability etc. My Mini and my A1 seem almost better or at least equal except for the materials they can print. And I have 2 Mini’s with AMS Lite and 2 A-1"s without as I can move them around if I desire. I will have to do some research on the Qidi but does it have any multicolor ability? Ihate decisions and in the end I will probably get a Qidi if my research makes it possible for multicolor and an X1C. They can replace some older Creality CR10 series slow dinosaurs. 
And spare parts/consumables pricing and availability is very important to consider too. And ease of do it yourself repairs too.
Added: I found that the Qidi is compatible with the Qidi Box that will be out in Q1 of 2025 for the color changing option but no price yet.
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Take your time with the adaptive layer height. Min/Max factor between 0 and 1 makes big differences. I have not found a use for the smoothing though. Seems superfluous.
As for decisions, I find those relatively easy. It is the subsequent justification that takes some time 
And it does sound like you are well on that road already 
I can make it a bit more tricky though to buy you time: Quidi seems to have had a very rapid release tact this year. Lessons learned implemented in each. If they want to/can keep that tact, there should be at least one more Quidi before the next Bambu…
I will take my time as I am sort of getting caught up around here. Noted on the smoothing.
I am just finishing setting up the second pair of printers, an A1 and an A1-Mini. Did the firmware updates and and doing another calibration after that. This time without doing them both at the same time on the same shelf of the bench they are on just to keep the vibration from one affecting the other etc.
Sometimes when a company does too many releases it makes you want to wait or be sorry you didn’t, if the next release is way more better! I will be patient for a bit to see what holiday sale prices may be although the Qidi is $200 off right now. One problem is most local people I know that I could sell a few old printers to, aren’t the kind of people that have the skills to make one work and I would end up babysitting and fixing all their issues. And mailing one through the mail is expensive. So I will just keep my old ones but man do they seem slow compared to my Bambu stuff. 
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