Polishing/sanding/chemical smoothing?

I just printed a decorative base to a model, and sorry I can’t post a picture at this time but it looks like a large coin, with detailed writing around the edge of the coin and across the face of the coin. When printing it, I printed it face up, so that I would minimize the support structure interfering with the inscriptions around the edge of the coin/base. This worked great, except that the print has a fine “Layered Grain” over the majority of it. I’m printing in Grey 4, and am wondering is there a chemical smoothing process that would “soften” the overall surface? or will I need to manually sand every surface to achieve a better, cleaner finish? I’m printing in LowRes .


How thick is the base? It sounds like you’re printing directly on the build platform, is that correct?

Hi Kat,
The base is approx 1/2" thick. And it was printed at a slight angle with a support structure- not directly on the build platform.

Is it a hollow base, or solid? Sorry for all the questions…can you do a screen shot of PreForm?

Also, in the beginning I thought that I would expect perfectly smooth prints…over time, I’ve realized that I can easily sand to get that smooth surface, and I plan for it with the design. If it’s at a slight angle, it sounds like that’s just the layers/slices showing up. I’ll also make choices about recessed text/raised text based on whether I’ll need to sand a little to get that smoothness.

I haven’t used any chemicals on mine…I know that using some sort of acetone bath or other with filament/FDM printers is pretty commonplace because it “melts” the plastic and makes it smooth. I’ll be curious to see if anyone is doing this with their Form printer and resins.

I found this older thread…apparently it’s called “vapor polishing” in the filament printer world…

Right on, I’ll give that a shot.

Thank you Kat.


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If it’s thin then it will help to make it a little thicker so that it has more stability, for something with a flat side then it’s easy to then sand it to the required thickness afterwards.

As far as smoothing, there isn’t any chemical option, the vapor polishing technique from FDM printers doesn’t do anything with this type of resin, instead the only automatic option is to use something like an air eraser/sander which basically just blows fine particles that will lightly sand the surface evenly.

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you can also just apply a fine coat of semigloss or gloss paint.
at 25 microns, the thinnest coat of a paint with vehicle surface tension should result in a very smooth surface.

Just be careful not to overapply.

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Oh, something I’ve started to use quite a bit is this:

They are four-way buffers that can sand supports nicely, then progressively polish them down, even to a shine. They are also available at beauty supply stores like Sally Beauty.

I took a silversmithing class and they gave them away as part of the class kit. I’d been buying larger sets of emery boards for jewelry…this particular buffer has the perfect assortment of grits.

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Kat, this is great too. I’ve been using 220 down to 320 grit sandpaper by hand and with a dremel tool.
Any idea how fine of a grit the Tropical Shine 4-way would be compared too?

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I have something like this that i stole from my girlfriend. Its meant for nails i guess, it has something like 7 sanding surfaces, the lowest being something like 240/320 and the finest must be something like 5000, it’s ultra fine and really just there to polish. Pretty useful to remove the support pimples from something with a surface texture

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My personal results with alternatives to manual sanding have been pretty poor.

If you have a large number of items you could try something like a rock tumbler with some very mild material to work to a polish, but if you are talking a one-off it’s time to sand.

Wet sanding can work well on the resins and leave you with a pretty nice finish. I would personally start at something like 300 and work my way up to finer until I was happy.

Haha! “Support pimples!!” :smile:

@Paraglyphs, my guess is that the coarsest grit is a 400, then maybe a 600, then 800, then one that is very smooth and buffs to a shine? I used to go through the whole course of grits with my emery sticks so I was skeptical of this. For the jewelry class I was in, this provided everything we needed to bring our pieces to a high gloss finish (silver).

They seem a little expensive for what they are, but what I was using previously seemed like overkill and I wasn’t using all of the grits. https://www.riogrande.com/product/Hermes-Sanding-Board-Assortment-Pkg-of-6/337458 . I think the Rio Grande option is still more cost-effective because three single-grit boards are like $5 if you know what you need (I was purchasing the assortment). But the Tropical Shine are pretty convenient, and you get to know the colors (they are also numbered) so sanding in progressively finer grits is very easy.

I have a bunch of different sanding options, you can get a lot of different sandpaper for cheap depending on what you’re doing. For some parts I use a micro-sander since it does it very quickly. For high detail stuff I found a set of 600 grit needle files that I use very carefully. I also have some micro-mesh sanding cloths to get things very polished.
For clear if you want to get it very transparent and your only option is to sand it then you need to get a full set of sandpaper and do wet sanding very thoroughly and take your time.

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